upgraded FETs

[Wedginator]

o wow, its been a while since i posted... anyways, I replaced the Xmods' stock FETs with 4562's. I had some left over from stacking mini-z FETs.

At the moment, the FETs lie 2x1 cuz of the heatsink in the way (and of course, i'm too lazy to cut the heat sink). I don't notice too much of a difference cuz i'm using a stock motor but I do notice some torque increase. Before the modification, I couldn't tire spin, but after, i can spin the tires whenever i want when i bury the throttle.

I'm hoping to get a faster motor so I can feel more of this upgrade.

Sorry, I can't post pics cuz my digi-cam is horrible and can't make out the words on the FET. But however, I'll try to take pics of the stock FETs cuz they have this white goo visible on it.

[neurokinetik]

Stock FETs are 2SA1792. Four of them are used, two on the top of the board, and two on the bottom. Not sure if this is how the Mini-Z does it or not, I only saw stacks of two in the pics.

I posted on Mini-ZRacer about an idea to use much larger FETs instead of stacking the small ones (though I didn't say it was for an XMod ;) ) and I still think this is the way to do it. It avoids the heatsink problem (Heat sinks would be attached directly to TO220 packaged FETs) and allows you to pass as much as 70A through them. Of course at this point, thicker wires will be needed, and traces on the boards might need to be beefed up as well. But the reliability of such a setup should be far better, and more cost effective. Such a setup would cost about $10 for the FETs (two each of N channel and P channel would be required), and a couple of bucks more for the board and wires, and would be the equivalent of having more than 10 stacked FETs.

I just need to order my parts and test this setupto be certain it works.

[mbartell]

Do you think that by having fets on the top and bottom of the board, it already has a "stack" built in?
Now the othere thing I'd be wondering- do you put the new added ones on the top or the bottom? Or both?
One extra on each?

[neurokinetik]

That's what I'm thinking. I need to examine the circuit board more closely to make a determination, but my initial look led me to believe that we are getting four FETs to run the motor, rather than just two. If that is indeed the case, then it really wouldn't matter which way you stack (up or down), as they are all connected the same anyway.

[Wedginator]

The FETs on the bottom run the motor, and the FETs on the top run the steering servo. There's no point changing the servo FETs unless you want super high speed steering; which is kinda a waste of FETs....

[neurokinetik]

What we really need to know is what the specs are on the stock FETs. I have been unable to find them anywhere so far. If I knew who made them, it would help, but they only have part and lot numbers printed on them with no maunfacturer's logo. A1792 is what they say, I'm assuming they are 2SA1792 (Toshiba). They could actually be UPA1792 (NEC).

[mbartell]

Well, the only way I can figure it out would be to see what it can take, and compare it to what the known values are.... ummm I don't want to do that. I can wait.

[neurokinetik]

Originally posted by mbartell
Well, the only way I can figure it out would be to see what it can take, and compare it to what the known values are.... ummm I don't want to do that. I can wait.

In theory, the manufacturer should have a data sheet out for the stock FETs. International Rectifier is really good about this, putting all of their data sheets online. Once we figure out who makes these things, then we can probably get this data.

Anyway, I ordered four of the big TO220 style FETs today from Digikey, and also a set of 10 IRF7389 FETs in case the other method doesn't work out.

[rmyc]

what's the diff of the P-channel and the N-channel power rating(Amp)..

which one is this one i should go by....i belive the p-channel is a negative amp rating and the n-channel is positive...

[1fastRSX]

i just bought an rsx x-mod friday and im hooked...i already bought the handling upgrade and the stage 2 engine upgrade...could some one clue me in on all the abbreviations... fet, nml, and so on?? thanks

[neurokinetik]

Originally posted by 1fastRSX
i just bought an rsx x-mod friday and im hooked...i already bought the handling upgrade and the stage 2 engine upgrade...could some one clue me in on all the abbreviations... fet, nml, and so on?? thanks

FET - Field effect transistor, used in the...
ESC - Electronic Speed Controller
NML - No Motor Limit, an individual that hand winds and assembles motors.

[1fastRSX]

So what does all of this mean?

[Wedginator]

read about FETs ESCs and NML at http://www.mini-zracer.com

do a search there and you'll find tons of topics that discuss this in extreme detail... in fact, so much detail, that you'll be able to teach a class....

[pacificwarriors]

how do you get the old fets out 2 put new ones in i am new so just curious.

[Wedginator]

You'll need to unsolder the old ones first.... then replace it with the new ones....

[neurokinetik]

Well, experiment phase 1 is a success. I replaced the stock FETs with IRF7389s, and everything works! :D

http://users.adelphia.net/~neurokinetik/7389.jpg

Now it is time to remove them and begin phase 2...

[neurokinetik]

Well, phase 2 is built, but not working at this point. Time to troubleshoot. The FETs I have chosen may not have the proper characteristics for this circuit.

Here's some pics showing what I have attempted.

The first pic shows the add-on board with the new FETs:

http://users.adelphia.net/~neurokinetik/FET_board.jpg

The second shot shows a closeup of the soldering of a CAT5 wire to connect the ESC to the add-on board.

http://users.adelphia.net/~neurokinetik/ESC_closeup.jpg

The last shot shows the entire electronics of the XMod with the add-on board attached.

http://users.adelphia.net/~neurokinetik/complete_circuit.jpg

[mbartell]

great to hear about stage 1!
I can see where stage 2 would be a problem.... that's a lot o' wires.
How do the mini z turbos do it, with only 4 wires?
They must be a lot more complicated than they look.

[neurokinetik]

Well, it depends. The "twin turbo" setups probably use 8 wires as well. Most of their turbos are only for the forward direction. I could concentrate on that as well, if I wanted.

What's important is that I have confirmed for myself that the main drive circuit of the XMods ESC is virtually identical to that of the Mini-Z. That opens up alot of possibilities.

BTW, the wiring isn't that bad at all, it took me about an hour and a half to build that entire setup from start to finish.

Anyway, if I get this working, it won't really be a stage 2, it'll function more like a stage 20...

[FESCSteve]

Is there no room to stack the IRF FETS?

[mbartell]

nope, they would stick thru the bottom of the chassis. Good for airflow, but bad for anything hitting it.... Unless you flipped over the board, or re-oriented it in some way.

[neurokinetik]

Flipping the board might be a possibility. You could also use a decent heatsink on top of them if you did this. I've got the perfect one from cooling cache RAM chips on overclocked Slot A Athlons. I have six of them from that project, and one of them will exactly fit the two FETs side-by-side.

[Nathan]

The mini-Z turbos send power directly from the batteries to the motor. They connect to the stock FETs and are simply a set of 4 more powerful ones. This way they are easy to install and bypass stock electronics entirely. I'v been thinking of building a simple one with RadioShack MOSFETs. This way I don't need to solder or mess with the PCB, just solder wires to the batteries and use those black connectors for the motor and motor output.

[neurokinetik]

Originally posted by Nathan
I'v been thinking of building a simple one with RadioShack MOSFETs. This way I don't need to solder or mess with the PCB, just solder wires to the batteries and use those black connectors for the motor and motor output.

You'll still need to connect to the board... How else are you going to get the signals to the MOSFETs to turn them on? Also, check the Specs on the MOSFETs that RS sells. They are IRF510, which are only capable of handling 4A continuous. The IRF7389 handles almost double that, and the MOSFETs I am using handle 10x what the IRF7389 handle.

Anyway, I've been doing some testing, and it appears that my circuit is fine, but one of the two types of MOSFETs I chose is not suitable, and I think it is the N channel. The circuit is not working because the drains on the N channel FETs are not staying at ground when they are supposed to, while the P channels go to 5V. What you end up with is 5V on both the positive and negative sides of the motor, and no voltage difference means no rotation.

What I have learned about this motor drive circuit:

IC5 controls the reverse voltage, and IC6 controls the forward. When you want to go forward, the gate on N channel FET in IC5 goes to 3.5V (not enough to turn the transistor on), and the gate of the P channel FET in IC6 goes to ground, which turns the transistor on. The output (drain) of IC6 goes to 5V, and spins the motor forwards.

The issue with my circuit is that I need to change my N channel FETs to logic-level ones, so that they are not turning on when they are not supposed to. Once this is done, the circuit should work just like the stock one, but with more than 10 times the current capacity.

Here's a couple of pics of the revised circuit. It's down to seven wires now, as I noticed that pin 1 on both IC5 and IC6 are grounded.

http://users.adelphia.net/~neurokinetik/FET_board2.jpg

http://users.adelphia.net/~neurokinetik/complete_circuit2.jpg

[SKYHIGH]

I am very new to xmods and mini-z tech stuff. I read for quit a while last night about stacking the FETs, but you have a seperate board and is that what the MOSFET your are talking about is? Also where are you going to install the extra board

[neurokinetik]

Originally posted by SKYHIGH
I am very new to xmods and mini-z tech stuff. I read for quit a while last night about stacking the FETs, but you have a seperate board and is that what the MOSFET your are talking about is? Also where are you going to install the extra board

The little 8 pin chips that the speed controller uses are the MOSFETs. Each chip contains a pair of MOSFETs, one N channel, and one P channel. Most people parallel a bunch of these chips by soldering them on top of one another to maximize their current capability. Instead of doing that, I am using much higher current devices that replace the chips with two MOSFETs each. These devices give the same or better capability as stacking up 10 of the small chips, which would be both unwieldy and not really possible where the board is located, even if you were to flip it over (the driveshaft ends up in the way). The small board will probably be attached to the roof of the car, like the light module is.

Obviously, with this setup, you won't be able to run the light module, but if you are really going for maximum performance, you aren't running the lights to begin with. ;)

[SKYHIGH]

With the seperate board and FETs would you be able to run a 5 or 6 cell set besides the lack of room

[neurokinetik]

With this setup, I can run up to 55V. :eek: Well, at least the motor drive circuit will be able to handle it. The rest of the board OTOH... :lol:

Actually, if I replace the steering servo FETs with IRF7389s, I could run as much as 30V with little risk of frying things.

[Microfied]

How much will this FET upgrade cost me and where can i purchase them?

[FESCSteve]

What is the stock FET rating? The reason I ask is that I am running 8.4V on a stage 2 yellow motor (next to highest speed motor - lots of current draw) and the controller seems to be taking it fine.

At this voltage, I can't drive it through turns as fast as it can go - it simply does flips. I wonder what the gain on adding the higher current capacity fets will be? I know that the on resistance will be lower, but you will probably negate any benefit with the long wires to the FET board. And I can't see anyone wanting to go much faster than 20-25MPH with one of these.

Of course, there are the hard-core speed freaks out there I suppose, but you reach a limit where the power simply is not useable abymore without increasing size or weight to keep it on the ground.

I guess I need to take some current measurements to get a baseline. Remember that as you increase voltage, the current goes up too.

Good luck on the project though - I am interested in the final product.

S

[rmyc]

yeah... the stock fets can handle up to 10v @ 2.9ah

[neurokinetik]

Originally posted by FESCSteve
I wonder what the gain on adding the higher current capacity fets will be? I know that the on resistance will be lower, but you will probably negate any benefit with the long wires to the FET board.

Not true, as those wires are only carrying the signal to turn the FETs on. From that board, they go right to the motor, and I can also use thicker wires to make that connection as well, further cutting losses. Cutting power losses is only a beneficial side effect of what I am trying to achieve. I want to be able to run any motor I choose. I want to achieve that goal wihout having to build big towers of FETs that won't easily fit into the XMod chassis.

Originally posted by rmyc
yeah... the stock fets can handle up to 10v @ 2.9ah

...and you have found this information where? I'm assuming you mean 10V @ 2.9A, because AH is a rating of battery capacity, not current capacity. 10V @ 2.9A is 29W. I highly doubt that the mystery manufacturer has come out with chips that can handle 10x the current without adding better forms of heat dissipation.

[raven5x]

Wow, I love the use of the board!! So what type of results should you see when you replace the FET's?? I can get them wholesale(from a friend) but I don't know if theyre worth changing. I'm assuming that the better the FET combination> the more the wattage put into the motor> thus faster RPM in the motor and shorter lifetimes for the circut??

I'm not at all new to MOSFET chips becuase you can take them out of old car amps, but what ya'll do w/ ur XMODS is ultimately crazy!

[neurokinetik]

It works!!!

I just got my new N channel FETs in, soldered them in place of the other ones I tried, and it works! No delay issues, just smooth power. Bench testing the setup with a Stage 1 motor, I could hold full throttle for a couple of minutes, and the heatsinks on the transistors are still cold to the touch, while the motor is warm.

So here are the transistors you need:

N channel 2x IRL3705N $2.60 each in single quantities
P channel 2x IRF4905N $3.21 each in single quantitiies

Total cost of the parts excluding the small circuit board (about $3) $11.60

Here are the specs...

IRL3705N:
VDS: 55V
ID (Cont): 77A
RDS(on): 0.01 ohms
Max power dissipation: 130W

IRF4905N:
VDS: -55V
ID (Cont): -64A
RDS(on): 0.02 ohms
MAx power dissipation: 150W

Compare these to the numbers on the IRF7389:
VDS: 30V
ID (cont): 7.3A (N channel) -5.3A (P channel)
RDS(on): 0.029 ohms (N channel) 0.058 (P channel)
Mx power dissipation: 2.5W

What does all this mean? Well it means that for the price of a 3x3 stack of IRF7389s, you can get the performance of a 10x10 stack*. Bring on the hottest motor you want, I think you'll find that the batteries will now become the limiting factor in how much current you can draw.

Oh yeah, I got all my FETs at www.digikey.com


*Max power handling and current capability is 10x that of the IRF7389, but the RDS(on) value is only half to a third of that of the IRF7389. This means that you don't get as much of the benefit of the decreased resistance as you would get with a set of stacked IRF7389s. However, we are talking about really small amounts of resistance here, small enough that you should be worrying about the wires connecting to your motor more than the RDS(on) value.

[platinum_player]

wow :eek: that is amazing, i wish i knew how to do this upgrade because i got an mini-z 4th Generation Modified Motor and i would love to put it in my xmod, do you know anyone who can do this for a small price, i would love to have this in my car so i could run just about any motor that i want thnx

[neurokinetik]

I'll post some new pics and findings later on tonight, but last night, I revised the FET board, and rewired the whole thing again. Now the MOSFETs lay flat on the board, and the board itself is only half the size that it was before. I improved the routing of the wiring, making it easier to install the FET board where I want it, and also switched to stranded CAT5 for the wires, which are more flexible and easier to work with. It fits well enough that I can actually get the C5R body on with it in place, though it doesn't quite sit as low as it should. Stock XMod bodies should fit no problem, I just need to transfer over my body mount and wheels from the RSX and shorten the wheelbase to see if it fits.

[TypeZer0]

why wouldn't the lights work? i thought the lights would be wired separate from teh FET circuits.

[neurokinetik]

Originally posted by TypeZer0
why wouldn't the lights work? i thought the lights would be wired separate from teh FET circuits.

The lights wouldn't work in my case because I removed that (unnecessary) part of the circuitry... :p

Actually, the problem is that you run out of space in the roof of the car with two boards up there, not to mention you'd have to put something between them to prevent shorts.

[neurokinetik]

Here's some pics of the revised circuit.

http://users.adelphia.net/~neurokinetik/roof_revision2.jpg

http://users.adelphia.net/~neurokinetik/installed_revision2.jpg

Initially, running it in the heavily modified chassis with the C5R body, it seemed slow. The motor was the Mini-Z Racer Z130-A-BB, which I've not been very impressed with (neither fast nor torquey). I was using the 8 tooth pinion. Well, that paricular chassis has a bent driveshaft, and the rigged C5R wheels, so it wasn't performing optimally. Bench testing the same motor connected to a normal chassis and comparing it to the FET modded chassis showed that there was no discernable difference in the peak motor RPM. Acceleration was hard to judge by ear.

So, I did some major parts swapping, basically swapping over the entire rear pod off the good-running RSX with the tweaked stage 2 drag motor (timing advance) a normal set of wheels and tires, and gave it a run. I thought the throttle response was soft when I was running the other setup, but not anymore. Its quite punchy and quick. Hard to keep it straight on full-throttle application now. Best of all, it fits under the stock RSX bodywork. I'd post a pic of that, but it just looks like a normal RSX. ;)

[EMX]

Originally posted by neurokinetik
Here's some pics of the revised circuit.

http://users.adelphia.net/~neurokinetik/roof_revision2.jpg

http://users.adelphia.net/~neurokinetik/installed_revision2.jpg

Initially, running it in the heavily modified chassis with the C5R body, it seemed slow. The motor was the Mini-Z Racer Z130-A-BB, which I've not been very impressed with (neither fast nor torquey). I was using the 8 tooth pinion. Well, that paricular chassis has a bent driveshaft, and the rigged C5R wheels, so it wasn't performing optimally. Bench testing the same motor connected to a normal chassis and comparing it to the FET modded chassis showed that there was no discernable difference in the peak motor RPM. Acceleration was hard to judge by ear.

So, I did some major parts swapping, basically swapping over the entire rear pod off the good-running RSX with the tweaked stage 2 drag motor (timing advance) a normal set of wheels and tires, and gave it a run. I thought the throttle response was soft when I was running the other setup, but not anymore. Its quite punchy and quick. Hard to keep it straight on full-throttle application now. Best of all, it fits under the stock RSX bodywork. I'd post a pic of that, but it just looks like a normal RSX. ;)
So would you say its worth the work to do this?

so basicaly now, I can put any motor in my XMOD and it "should" run now? also what about more power? or is more power needed?

[neurokinetik]

I don't really think there is any more work involved in doing it this way than stacking 4562s or 7389s. This is equivalent to two stacks of 10 each (one for forward, one for reverse) of the 8 pin ICs. That's 160 solder connections to make. This method involves about 35 solder connections.

At this point, it would take a truly sick motor to kill these MOSFETs. I'm going to push the limits on it and wind something like a 10 turn motor to use with them. The current draw of the motor could cause some issues with the radio and steering servo, but I have a solution for that as well. I also plan to upgrade the battery wires and all power connections right up to the motor.

As far as adding more power, it could be done, but it is not required. I want to see what can be accomplished with just 4 cells at the moment, before moving on to bigger power sources.

[TypeZer0]

i really like the progress of your turbo unit.

what if you used 4 smaller batteries or a li-poly to power the ESC and dedicate the 4 aaa's to the motor? or move it up to 4 AA's which may allow a higher constant current drain tahn AAA's.

jus wondering, are you going to provide us wiht a schematic?

[rallger]

**dont read this if u get peeved by noob question***

what ter heck is a fet and why are u stacking tehm?

[bob256]

hey in my other thread about the 180 size motor and upgrades i talked about using a low voltage drop regulator to control voltage and current to the radio assembly. this type of regulator would limit the voltage and curret when the voltage from the batteries are as low as .45 v above the required voltage, i.e. 5.45 v needed to regulate 5v @ 500ma. i have been thinking of setting up a circuit where a group of 6 six cells are made in to 2 custom battery packs and then put in parralel with the motor and radio w/regulator, batteries in the center
(bad ascii art)
# # #
#(radio)---<<5v@500ma--#(regulator)---#<<(battery)>>(fets)
# # #

I think this would allow running of the lights w/o blowing the board. i testes the xmods board to find out the max current draw
and here are the results
car on, no servo motion(including holding the wheels straight) the car draws about 22ma, with servo moing back and forth it draws about 100-130ma, and with the servo holding wheels against an opposing force the board w/servo draws about 130ma with spikes upto 150ma, so 500ma should EASILY run the radio and lights, i choose 5v because it's a standard value for voltage regulators. now the problem is SPACE!!

FYI i hooked up the gate of the p and n channel fets that form the h-bridge to a scope to test for the BW needed for the mosfets and the board(ESC) switches from 3.5 to 5v @356hz, just like wedginator said

[bob256]

WHOOPS, just like neurokinetik said

[Pinoy274]

amazing work neuro... simply amazing...

if you ever find yourself interested in adding lights again.. and want to prevent shorts... you may want to consider shrinkwrap around your turbo board...

anyway... by how much does your run time decrease with this much draw? just curious, because i'd like to know how many sets of rechargables i should have on standby should i attempt this and attend a competition... `=]

[neurokinetik]

Originally posted by Pinoy274
amazing work neuro... simply amazing...

if you ever find yourself interested in adding lights again.. and want to prevent shorts... you may want to consider shrinkwrap around your turbo board...

anyway... by how much does your run time decrease with this much draw? just curious, because i'd like to know how many sets of rechargables i should have on standby should i attempt this and attend a competition... `=]

I'm still trying to figure out how to heatshrink the board while keeping the heatsink tabs on the transistors open. As for run time, I ran it for about 15 minutes this weekend with no issues (transistors never even got warm), then the following night for a couple of minutes, after which the entire car went dead. I haven't had a chance yet to tear it down and find out what went wrong. I did get a chance to line up against other XMods, and found that I was still significantly faster than others who were running stage 2 (drag or drift) motors (I am running a stage 2 drag with timing advanced). Runtime won't decrease with this mod, as it is just an "enabler". It doesn't really provide much of a performance increase, it simply allows you to run a hotter motor without worry.

[Pinoy274]

ok cool...

in that case, may i ask, what is it exactly that you're soldering the CAT5 wire to upon connecting the boards?

[neurokinetik]

Originally posted by Pinoy274
ok cool...

in that case, may i ask, what is it exactly that you're soldering the CAT5 wire to upon connecting the boards?

I solder directly to the pads where the old FETs used to be located. If possible, I look for the largest open area to solder to, scrape the coating off the trace, and attach the wire there.

[EMX]

I have seen neurokinetik's set up and all i can say is "wow"

its faster then mine, and im running a stage 2 drag and so was he, we both had stock bearings.

[bob256]

Neurokinetick advised to scrape the traces the fets are attached to, but i have found it much easier to use 30 gauge wire and prep the wire right. strip the wire, add a little bit of solder to the wire, and while it is still hot, stick the wire to the leg of the fet where the gate is located, it should stick just fine. Neurokinectick's way works just as well, but i thought i might post this advice if you ever feel the need to return your car to normal without a trace :)

[neurokinetik]

Originally posted by bob256
Neurokinetick advised to scrape the traces the fets are attached to, but i have found it much easier to use 30 gauge wire and prep the wire right. strip the wire, add a little bit of solder to the wire, and while it is still hot, stick the wire to the leg of the fet where the gate is located, it should stick just fine. Neurokinectick's way works just as well, but i thought i might post this advice if you ever feel the need to return your car to normal without a trace :)

I always tin both the wire and the spot I am soldering to. Makes for a quick, strong connection. http://www.tinyrc.com/forums/images/icons/icon14.gif

[TypeZer0]

i'm wondering, are you gonan show a schematic showing where to connect each pin to what pad on the circuit board?

[neurokinetik]

Originally posted by TypeZer0
i'm wondering, are you gonan show a schematic showing where to connect each pin to what pad on the circuit board?

Yeah, as soon as I can draw one up. It's really quite easy.

[Mr BigShot]

Hows it going with the upgrading Everyone . I've seen a few 4 or 5 stack Fet upgrades for sale on E Bay for sale . Hey Neurokinetik were have you disappeared too ? :) How's your project doing ? I went out and bought a low voltage soldering gun from RS ,15 volts, it looks like a big pen .Going to try upgrading my wire's first . I kinda new at this :D Hey what FET's are the best to use on an Xmod ??????

[neurokinetik]

Here's an illustration of what I have done:

http://users.adelphia.net/~neurokinetik/schematic.png

On the main board, IC6 is the chip responsible for driving the positive (red) motor wire. IC5 handles the negative (black) side. The graphic shows the chips how they appear on the board if you are looking directly at them, with the front of the car facing you. If you look closelty at the board, you will notice that one whole side of each chip is connected directly to the motor wires. This is the Drain pin of the MOSFETs, and as you can see, the drains of both the N Channel and P Channel MOSFETs are tied together within each chip. The diagram to the left of the picture shows the pinout of each MOSFET. It is the same for both the P Channel and N Channel. Both the center pin and the tab are connected to the drain within each MOSFET. Keep this in mind so that you don't inadvertently create shorts! Pin 1 of each chip is grounded, so as long as you tie the sources of both N Channel MOSFETs together, you only need to run one wire from the MOSFET board to the main board. The rest of the wiring is pretty straightforward. Just wire up two pairs of transistors, an N Channel and P Channel in each pair, solder the drains together, and connect the motor leads to them.

I can probably draw a complete schematic, but this should give a pretty good idea of how to do it. Basically, pretend the outlines of the ICs aren't there, and solder the corresponding pins of the MOSFETs to the proper place on the main board.

[D1drifter]

hi neurokinetik, Im new to the tiny rc forums but certainly not new to RC. I am in aww in what you have done with the custom FETs mods. Im very interested in doing this Mod to my xmod myself although with the current schematic diagram you have post, I really can't get the whole picture. If you can post the complete schematic diagram, that would be a great plus. thanks neurokinetik

[Mr BigShot]

It is quite hard to understand ! I have all the soldering stuff , and soon i will be ordering SI4562DY's <---- are these the ones to use ? for a stack of like 4 or 5 high? Well Thanks for all your hard work with the FET's wish I had the smarts to understand that diagram :D

[TypeZer0]

i was curious when you did phase 1 with the IRF7389 FETS. did you happen to test out that configuration? i'm thinking of using these because they're drop in replacements but not stack them since i'm not gonna go hardcore with like 10 turn motors that make full use of that turbo board you made.

[neurokinetik]

Originally posted by TypeZer0
i was curious when you did phase 1 with the IRF7389 FETS. did you happen to test out that configuration? i'm thinking of using these because they're drop in replacements but not stack them since i'm not gonna go hardcore with like 10 turn motors that make full use of that turbo board you made.

I tested it on the bench, but not in the car. It worked transparently compared to the stock FETs. Remember that we still don't know the specs on the stock FETs, they may actually be as good as IRF7389s. If that were the case, then you'd gain nothing by only swapping a single pair in.

[D1drifter]

can the turbo board you fabricated handle a hand wound 9-turn motor?

[neurokinetik]

Heatsinks would likely be needed, but I bet it would hold up fine. As Nathan pointed out in the other thread, though, it is unlikely you could get enough current from the AAA batteries to run such a motor to its fullest potential.

[D1drifter]

Thanks for the insight. Well im very intererested in doing this particular turbo mod over the stacking of FETs method due to the fact that i can run any more i want without the risk of burning out the circuits. I finally figured out the shematic diagram you posted, though it took me a while:p. I do have a question, With the stock motor, what kinds of performance increases are noticable with "turbo board" as opposed to "FET stacking" Thanks again with your helpful advise

[EMX]

Brett, You took out IC5 and IC6 right?


also, have you found any problems since then?


and are you still using the FETS you specified?

[neurokinetik]

Yes, I removed IC5 and IC6 from the board, as they are no longer needed with my FET upgrade. I removed the aluminium heatsink from the bottom of the chassis as well.

Functionally, the circuit has continued to work well. Even the hottest motor I have tried hasn't gotten the FETs hot enough to burn my fingers.

The only problems I'm having right now is the durability of the connections to the main board. I've ripped traces offthe board twice now, though it wasn't all that bad and was easily repaired. Obviously there needs to be some sort of strain relief on the wires. Also, I'll probably find that when I go to the Plasma Dash motor, I'll need to upgrade a couple of the wires, as the CAT5 probably won't handle 4A of current.

I'll probably be revising the layout one more time, possibly putting everything in a line. The reason for that is I can't fit six cells in the car with the FET board right now, there just isn't room. Even in the MINI Cooper body.

I also want to be able to fit the power capacitor in there as well. That may be changed to a group of smaller caps in parallel, because the 10000μF cap I am using now is too bulky to fit in the places where I have extra space.

[EMX]

cool

where are you going to put the 10mF cap?

[neurokinetik]

I want to put it just behind the motor, on top of the white piece over the rear suspension. It's a little too fat to go there, though.

[FastRSX]

neurokinetik, I just received my Tamiya Plasma Dash motor today. So, did you get your motor yet and install that animal? I want to see if your fet up grades will work? Plus I really want to know how much power this motor has.

[neurokinetik]

Just got it today. Need to decide what pinion to put on it, and put my FET upgraded car back together. The only thing I can say right now is that the motor sounds pretty fast, but it draws 1.7 - 1.8A without any load. That's more than triple what a stage 2 does, in fact it's even more than my 25 turn custom armature.

It will be interesting to see what it can do.

[CooLJoE]

Think you'd need your setup for this motor?

http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXBEA7&P=7

Megatech Modified Hi Speed & Torq Motor
Turns: 21
Current: 0.8 - 1.9 amps


I'm curious because this is the motor I'm looking at for my Xmod. However I don't want to do a FET upgrade if I don't have to.

[neurokinetik]

Based on my experience with a 25 turn motor (even with Neo magnets), a 21 turn motor would be a waste of time.

[Evomod]

neurokinetik
Do you have a complete schematic of your FET upgrade? also how did you wire in your power CAP? :confused:

[CooLJoE]

Originally posted by neurokinetik
Based on my experience with a 25 turn motor (even with Neo magnets), a 21 turn motor would be a waste of time.

Why is it a waste of time?

Curious to know why as I'm new to Xmods, but not R/C (have over 10 years experience with R/Cs in general). I mean, it has to be better than a Stage 1 or Stage 2.

If that motor is no good, whats a better choice past the Stage 2 that doesn't need FET upgrades?

[LithiumXmod]

I did the same Fet upgraded as neurokinetik.

[neurokinetik]

Originally posted by CooLJoE
Why is it a waste of time?

Curious to know why as I'm new to Xmods, but not R/C (have over 10 years experience with R/Cs in general). I mean, it has to be better than a Stage 1 or Stage 2.

If that motor is no good, whats a better choice past the Stage 2 that doesn't need FET upgrades?

The reason that motor is no good is because the 130 motor generally does not have much torque. The other problem is that the AAA batteries can't provide enough current when you start getting into the low-turn motors.
It is different than with the larger motors, like a 540, for example, where they have alot more torque to begin with. The lowest number of turns I have successfully used so far is 35, and that is with 28Ga wire.

The best motor that doesn't require FETs that I've found so far is a 180 motor for the Micro RS4. The larger armature and magnets (about 50% larger) means you don't need as many turns to still have a usable motor. The GPM modified motor that I picked up is a only 35 turn motor, but it is not as fast as the Team Orion that I am using (with 10 less turns than stock. I don't know how many turns it actually has now). It draws only as much current as a stage 1 motor, has way more torque than even a Neo magnet 130 motor, but top speed is only about as good as a stage 1. However, put on the 11 tooth pinion, and blue gear, and you will find that the car will handily out accelerate even a stage 2 drift setup. No replacement for displacement.

Beyond that, taking a few turns off of a stage 2 and advancing the timing works well and doesn't increase the current draw enough to worry too much about. (Refer to the current draw thread for examples)

[neurokinetik]

Originally posted by LithiumXmod
I did the same Fet upgraded as neurokinetik.

Cool, glad to see somebody else has given it a try. How's it working for you?

[Evomod]

LithiumXmod,
Can you shed some detail on how to wire up the FET upgrade?
:)

[LithiumXmod]

The FET upgrade is working great. Then again i just have a stage one motor with 8 tooth pinion. I have a Pnracing S03 on order, im sure is going to push the fet's. Im still tryin to figure out a way to add heat sinks to keep the fet's cool. SIde mount, maybe? I used CAT5 cable as well, standard kind. As for wiring, look at neurokinetik picture diagram of the fet's. Its self explaintory.

[Evomod]

How is it wired back to the car?:confused:

[LithiumXmod]

Evomod you need to remove the whole PCB from the xmod and unsolder the fet's on the underside of the FCB. I drill a small hole on the side of the xmod, to run the wires from the underside of the pcb to the top. I'm sure there are other ways, but that's how i did it.

[neurokinetik]

If you are really creative with how you route the wires, it isn't even necessary to cut the chassis. Running everything through a hole could provide a much-needed way of providing strain relief, though.

[LithiumXmod]

neurokinetik what do you think of pnracing s03 motor?

[neurokinetik]

Haven't tried one, but it's supposed to be decent, for a 130 motor. If it sucks, at least you have a nice BB can with Neos to stuff a new armature in... :p

[LithiumXmod]

Yea, that's true. What kind of motor do you reconmend neurokinetik to take advantage of the new fet's? (stayin to the topic)

[neurokinetik]

Actually, the S03 is probably a good choice, or else a 35 turn motor that uses 28 Ga wire. That pulls some juice.

[LithiumXmod]

What motor are you using neurokinetik?

[FeRReT_of_WaR]

when you guys are done with this modding. can you post a step by step guide to fet upgrading. i kinda understand. but what does it mean by turns in the motor. i have taken a motor apart and seen the inside. and there were three arms how does the wire go around? is it like 15 or something turns for a arm and you move the wire on over to another arm?

[neurokinetik]

Originally posted by LithiumXmod
What motor are you using neurokinetik?

Well, I've got a nice little collection of experimental hybrids, but mostly I'm running 180 motors now.

[LithiumXmod]

neurokinetik, do you know where i can buy a replacement pinion gear?

[neurokinetik]

Yeah, you can get a set of four for $12.99 from Radio Shack. They'll even throw in four motors for free... ;)

Other than that, I have been unable to locate a really good replacement.

[LithiumXmod]

I just recieve my pnracing S03 motor today, Just finished installing the motor. I can say the upgraded Fet's are cool to the touch. The motor packs a nice punch from stop to go. Im happy with my upgraded Xmod. :) I will post pictures of my Xmod tonight.

[neurokinetik]

What gear ratio did you end up choosing?

[LithiumXmod]

4.80

[joe_t1g]

LithiumXmod I was considering the s03 for myself, how does it stack up against a stock stage 2? Is it a noticeable advantage to justify spending $25 on a motor?

=====

Neurokinetik, nice job with everything.

After hours of reading TONS of great topics by you I am finally ready to ask you a couple questions. I think I'm going to go with a Stage 2, decrease the # of turns to 44? (following your 'current draw' thread [could it be decreased any more?]), advance the timing and do a 6 cell upgrade. Probably not the fastest thing out there, but its the most cost effective at this point. This would make a 'fastER' motor at the expense of torque, so I was thinking of using SpinBrush magnets to improve the torque. 11t to balance out the speed & torque.

I wouldn't need a FET upgrade would I? I was checking your current draw findings and I estimate it would put it in the 0.60-0.70A range.

I don't want to stray off topic but what do you think of this setup? PM me if you'd rather not mix up the topic. Thanks, I've learned a lot from your posts!

[LithiumXmod]

Well, I have never used a Xmods Stage 2 motor. I went staright from a stock motor to a S03 motor. I like the motor, has a lot more punch compare to my stock motor. The neo magnets give me more torque, enough to spin my wheels. High end is great as well. Also keep in mind I don't use AA's, I use lithium photo batteries.

[LithiumXmod]

As promise, pictures.

Before

[LithiumXmod]

after:

[LithiumXmod]

another:

[Evomod]

Has anybody else done Neurokinetik's ciruit yet?

If so could you please post more detaild Pics and or instructions on how to wire up all 4 MOSFETS together. I am having difficulty understanding the schematic. Could you post the back of the finished circuit at a bettr angel, the one that is posted is hard to determin what is what.

Thanks :(

[Evomod]

Has anybody else done Neurokinetik's ciruit yet?

If so could you please post more detaild Pics and or instructions on how to wire up all 4 MOSFETS together. I am having difficulty understanding the schematic. Could you post the back of the finished circuit at a bettr angel, the one that is posted is hard to determin what is what.

Thanks :(

[neurokinetik]

Originally posted by joe_t1g
After hours of reading TONS of great topics by you I am finally ready to ask you a couple questions. I think I'm going to go with a Stage 2, decrease the # of turns to 44? (following your 'current draw' thread [could it be decreased any more?]), advance the timing and do a 6 cell upgrade.

I have run a similar setup to that with some success, but that was only with four cells. With six cells, the performance and current draw are completely different. Firstly, the motor is being fed more current (and voltage) by the two extra cells, and secondly the load on the motor is increased by the additional weight of the batteries. This increases current draw further. While it may be safe for the stock ESC on four cells, six cells would likely cause damage. Using an 11 tooth pinion only makes matters even worse.

[matrixled]

Evomod,
I am also having trouble understanding this circuit. I just need to understand how the 4 new FETS are connected/wired to getter on the new board. the pictures arn't doing me any justice. Im thinking on IC6 and IC5 do you wire S1 to D1 and than S2 to D2 Im not sure whare any of the G's go :confused:

Some help from neurokinetik or LithiumXmod would be nice.

[neurokinetik]

http://users.adelphia.net/~neurokinetik/schematic.png

Let me try explaining this again...

The two chips on the board, IC5, and IC6 each contain two MOSFETs. My FET mod replaces the chips with four new discrete MOSFETs that can handle more power. Each chip (shown by the pair of 8-pin devices on the diagram above) contains an N Channel MOSFET and a P Channel MOSFET. In my mod, the N Channel FETs will be IRL3705N, and the P Channel will be IRF4905. Hence, each A1792 on the board will be replaced by a pair of FETS, one IRL3705N, and one IRF4905.

A MOSFET has three connections: The (G)ate (G), the (S)ource, and the (D)rain. The gate controls the switching of the FET, whether it be on or off. The source is the voltage that will be passed through the FET, to the drain. The illustration the the left shows a TO-220 type MOSFET package, and the gate, source and drain pins are all labelled. Note that the heatsink tab on the FET is also connected to the drain. That tab and the center pin are the same connection.

With my mod, all you are doing is replacing the two chips with four MOSFETs. In the diagram above, you can see IC5 and IC6 as they are situated on the board. Simply connect the corresponding pins of the IRL3705Ns to where the N Channel FETs wired, and the IRF4905s to where the P Channel FETs were wired. The gates connect to the gates, the sources connect to the sources, and the drains connect to the drains.

Now, in the chips, the drain of the N Channel FET is connected to the drain of the P Channel FET. Do the same with the pair of FETs representing IC5 and IC6. The drains are the outputs of the FETs, and therefore, they get connected to the motor wires.

Don't get confused by what is shown inside the chips. That is simply the way MOSFETs are drawn. Just pay attention to what the PINs are on the chips, and note that S1 and G1 are for the N Channel FET, and S2 and G2 are for the P Channel FET.

When looking at the chips, and reading the text on top, pin 1 will be to the lower left. There should be a small dimple on the chip there as well.

[TypeZer0]

hmm, have you thoguht about connecting the source directly to the battery? would probably give you slightly less of a voltage drop

[Evomod]

Is this what you are saying?

http://www.geocities.com/mangolinux/

[TypeZer0]

i dont think tripod allows direct linking to pics, that's why i can't see it. same goes for the link right below it

[matrixled]

Try here
http://evomod.tripod.com

[neurokinetik]

I'll draw another diagram when I get home tonight...

[miketre]

Originally posted by TypeZer0
hmm, have you thoguht about connecting the source directly to the battery? would probably give you slightly less of a voltage drop

Connecting the source directly to the battery also allows you to mod it such that only 4 cells go to the board (and light kit too?) while all 6 cells (or whatever number within the FETs' limit) go to the motor.

Here it is on a Z, but the same concept should be applicable. ->My multi-cell mod (http://www.geocities.com/miketre.geo/5cell.htm)

I'm just throwing in ideas, don't flame me for being a Z-lover :p I do hope that RS decide to market the XMods over here.

P.S. Nice work Neuro!

[LithiumXmod]

My finished xmod

[LithiumXmod]

another

[neurokinetik]

I take it that it all fits under the body now? It looks much better. http://www.tinyrc.com/forums/images/icons/icon14.gif

[neurokinetik]

[QUOTE]Originally posted by miketre
[B]Connecting the source directly to the battery also allows you to mod it such that only 4 cells go to the board (and light kit too?) while all 6 cells (or whatever number within the FETs' limit) go to the motor.

Here it is on a Z, but the same concept should be applicable. ->My multi-cell mod (http://www.geocities.com/miketre.geo/5cell.htm)

I have to look at the board again and confirm the connections. There's probably another revision to be made. Doing it that way would allow for nice beefy wires that go right from the batteries, through the FETs and into the motor. It would also mean less connections to the circuit board would be needed, which would help in reliability.

That link looks like a good idea. I may have to try something like that. Hell, at that point, why stop at 7.2V? I'd go straight for 12V...

[LithiumXmod]

yup, everything fits under the body now.

http://tinyrc.com/forums/showthread.php?s=&threadid=16760

[neurokinetik]

Alright, now this should be totally clear to everyone...

*non-working circuit diagram removed. See below for the correct one...*

This is the as-yet-untested version with the sources connected directly to the batteries. That might also be a good place to wire in a power cap...

[matrixled]

Thanks this helps out a WHOLE lot:D

Which 7 pins connect back to the main board?

[LithiumXmod]

I will the circuit later tonight. Im at work right now.

[miketre]

Originally posted by neurokinetik
That link looks like a good idea. I may have to try something like that. Hell, at that point, why stop at 7.2V? I'd go straight for 12V... [/B]
Hmmm.... I don't think going more than 6 cells with a 35turn motor (S0-3) is a good idea. 12V should be less damaging to a motor with a lower current draw.

neurokinetik -> how's the battery life with the T0-220 FETs? Is it much shorter?
Both P and N channel FETs must be logic level ones right?

[LithiumXmod]

I just try the circuit, is doesn't work.

[neurokinetik]

Originally posted by miketre
Hmmm.... I don't think going more than 6 cells with a 35turn motor (S0-3) is a good idea. 12V should be less damaging to a motor with a lower current draw.

neurokinetik -> how's the battery life with the T0-220 FETs? Is it much shorter?
Both P and N channel FETs must be logic level ones right?

I haven't noticed any battery life differences, and I really didn't expect to see any. Both P and N channel FETs are logic level.

As for 12V damaging the motor, well, for my drag car that wouldn't be a concern. The 180 motor is designed to run on 6-12V, and that's straight from Mabuchi. Plus it only really has to last about 5 seconds or less... ;)


Originally posted by LithiumXmod
I just try the circuit, is doesn't work.

OK, then here is the circuit that has been tested, and does work. Note that Pin 1 on IC5 and IC6 is the same connection, so as long as you tie the sources of both IRL3705Ns together, only one wire needs to be run to the board to make that connection, hence 7 wires needed instead of 8.

http://users.adelphia.net/~neurokinetik/schematic4.jpg

[matrixled]

Thanks
What did you ground Pin1 (IC5 0r IC6) to? :p

[neurokinetik]

When you remove IC5 and IC6, you can see a big fat trace underneath them that was connected to pin1 on both chips, and is grounded.

If you attach to either pin 1 trace, it will ground the circuit. Alternatively, you could connect the wire to where the - battery wire attaches to the board.

[LithiumXmod]

Just finished wiring the grounds of the fet's to the battery. I cannot really tell if it made a differences.

[TypeZer0]

i'm sure you'll see a difference once you move up to high current draw motors....the difference being the fet upgrade can handle it while the stock fets simply melt

[neurokinetik]

Well, I now have the FET circuit hooked up this way. I thought it strange that LithiumXMod said that it didn't work, so I decided to try it myself. It actually does work, and now the only connections that need to go to the main board is the gates of all four MOSFETs. The rest of the connections are on the standalone PCB. Even a Plasma Dash wouldn't kill this setup now. Actually, even a Novak SPY can't handle the current that this setup can. :cool:

http://users.adelphia.net/~neurokinetik/schematic3.jpg

[rmyc]

haha sorry but i dont get the diagram.. which prongs attach to the esc?.... thanks

[neurokinetik]

Just ignore where all the lines cross unless there is a dot at the junction.

Basically, it works like this:

Connect the sources of both IRF4905s together, and then connect them to the positive (+) battery terminal.

Connect the sources of both IRL3705Ns together, and then connect them to the negative (-) battery terminal.

Connect the drains of one IRF4905 and one IRL3705 together, then connect that to the positive motor lead.

Connect the drains of the other IRF4905 and IRL3705 together, then connect that to the negative motor lead.

That leaves only the gate pins of each transistor unconnected. Connect the gates to the pins on the main board as indicated.

[LithiumXmod]

hmmm...maybe i connected something wrong. Sorry about that.

update: Is working :)

[Declyn]

If I was to wire the new FETs as described in the last schematic, could the servo and everything else on the original board opperate on just two AAA?? Leaving the other battery compartment for say a 9V wired to the FETs?

[scatmanjohn01]

ok neuro..
so if i wire it like in your diagram, do the positive and negative wires from the batterys still have to connect to the 2 gold disks that have (3) and (2) next to them on the pcb?

same thing doing a direct connect to the motor wires.. do the motor negative and positive wires have to be connected to the golddisks with (6) and (7) next to them on the pcb still? 0r can the positive and negative motor wires just hookup directly to the fets? thanks

[TypeZer0]

according to neuro's latest diagram, the battery will connect to the pins on teh FETs (but don't remove the existing battery wires from the pcb....pcb still needs juice :D ) and the motor now attaches directly to the FETs

[scatmanjohn01]

ok it still doesnt make an sense to me..

[TypeZer0]

just follow the diagram a few posts up. where he labels + or - battery, solder a wire at those pins and connect the other ends to the battery terminals. where he labels + or - motor, wire that up to the motor. wherever he labels IC6 Pin 4 or whatever, just solder a wire there then find where pin 4 of IC6 is on the pcb

[scatmanjohn01]

neuro can you post a pic of the pcb with your mosfets added
?

[scatmanjohn01]

yoohoo?

[neurokinetik]

I'll try to post one later, but I guarantee it isn't going to help...

[danny_v_l]

hey neuro, this i kindda confusing and i don't want to cause u troble but, i under stand the diagrams but how do u conect it to the esc, or does it just go to the bats and mottor, heres what i'm trying to say, ok u have a nice stock xmod and u wanna do this mod so u build ur little chip with ur fets on it then attach it to the bats and motor along with the stock wires?

[neurokinetik]

http://users.adelphia.net/~neurokinetik/ESC_closeup.jpg

This was the first revision, but the only difference is that there are now only four wires connected to the board instead of 7. You solder the wires directly to the board where the pins on the stock chips used to be located. It's not all that easy to do without a fine-tipped soldering iron and some practice. Still much easier than FET stacking though.


Here is a quick shot of bottom side of the board before the FETs are removed. (Actually, the FETS in this pic were swapped for a different part number, but they look the same.) The FETs are the two black rectangular chips in the upper left of the picture. In this pic, they say F7389 on them, the stock XMods will say A1792. Note that the same chips are used on the top side of the board to run the steering servo. See the little dot on the bottom left of each chip? That marks where pin 1 is. Pin 2 is the next one to the right, followed by pin 3, and Pin 4 is at the bottom right. The top side of the chip is pins 5-8, going right to left. Pins 5-8 are all the same connection on these chips. Look just above the right chip, and you can see that it is labeled IC5. The left chip is IC6.
http://users.adelphia.net/~neurokinetik/7389.jpg

[danny_v_l]

thanx

[danny_v_l]

hey i have a old burnt out rsx, can i take thosefets off abd stack them on my supra?

[SuPrBuGmAn]

neurokinetik - there is a user at XModRC thats using a similar FET setup on his Civic. He's using a voltage regulator to keep the board regulated to 5v while allowing as much power(well, to a point - 25v) as possible to the motor.

You can see some diagrams and info on the setup he's using here (http://pub238.ezboard.com/fxmodrcfrm8.showMessage?topicID=512.topic).

In your setup, are you still using a zener setup to regulate the board power or have you applied some sort of on/off Vreg to regulate your board as well?

I may attempt this mod, just trying to figure out the most optimal setup.

[neurokinetik]

Looks like he's saved me some work. :D I have two totally different projects going, one is using the FET mod, but the drag Civic is currently running on stock electronics. I was planning to merge the two projects and do some form of regulation down the road, but I hadn't gotten around to figuring out how I wanted to do it yet.

[neurokinetik]

Originally posted by danny_v_l
hey i have a old burnt out rsx, can i take thosefets off abd stack them on my supra?

Yes, you could.

[danny_v_l]

would i benifit from it, like power, accel?

[scatmanjohn01]

hey neuro with those fets that you upgraded to, whats the lowest number of turns possible on a mottor with put frying? also do you know the lowest number of a turns a motor can have with out frying a 3x2 stack of irf7389's? one more question... what on the esc board determines how much the voltage limit from batteries is? i mean like, how would you upgrade the board so it could run more than 8.4 (6 ic3) cells?

[SuPrBuGmAn]

IC3s put out 1.2v don't they? 6 IC3s put out 7.2v. It would take 7 IC3s to run at 8.4v.

Anyway, there is a guy on XModRC.com that will be running a 14.4v after upgrading the FETs and replacing the zener style regulation with an on/off voltage regulator(5v). He's going to be running (4) 3.6v Lithium Ion AAs to achieve the 14.4v incase anyone was curious.

[scatmanjohn01]

ic-3s are 1.45 v if im not mistaken. and yes i already read jshwaa's thread

[SuPrBuGmAn]

Originally posted by scatmanjohn01
ic-3s are 1.45 v if im not mistaken.

Maybe I'm mistaken? Who knows, if thats true I'm going to have to pic up some IC3s myself, the 15min recharge isn't enough for me to get them on its own..

[TypeZer0]

1.2 volts is their rating but all of the rechargeables i've seen so far puts out anywhere from 1.34 to 1.60 volts when fully charged. these energizer 750mah cells i got from walmart (bit less than 10 bucks for a package of four) are 1.6 volts when fully charged and maintains at least 1.3 when they're close to depletion. in fact, i had a hard time getting them to charge in my radioshack charger because the xmod battery charger has a voltage detector and if it's too low or too high it wont' charge and well, the energizers were too high lol. i'll probably look for the 30 minute energizer charger i saw somewhere

[Doctoraudio]

neurokinetik

Can you make me one of those fet boards ready to solder on?
Thanks!

Team Insane X-Mods

[xxspeednplayaxx]

hey neuro, great mod, im more than sure im going with a team orion motor reduced to 35 turns. i went to rcmart.com and am about to order t.o.s. motor, a 10T pinion (set screw), but i also have the 12t pinion so ill have to see which feels best 2 me. now i plan on doing a fet mod... so by using the IRF7389 and IRL7389 (i dont think i have the # right, ill check before ordering) anyways all i have to do is purchase 2X of each fets listed, and wire them in the fashion of the diagram you posted and my t.o.s motor will be fine?

How many volts could that setup handel? another question is: would r.s. carry these fets?

im also curious as to how many volts a t.o.s motor could handle?

my current motor (that beastly thingy) currently gets the underneath of the chassis hot after about 5 minutes of use, will the fet mod listed in this post solve that problem, and also whats the maximum volts i could run through the chip to my beast motor while keeping the chipset safe (considering im only out for the safely of my board, the motor was under 5 bux)

im sorry for all the question, but i just wanna be sure before i put about a weeks worth of money into my xmod.. thnx!

[neurokinetik]

Originally posted by xxspeednplayaxx
im sorry for all the question, but i just wanna be sure before i put about a weeks worth of money into my xmod.. thnx!

Short answer to long questions... FET mod isn't needed for that motor. Six cells on that setup is plenty safe. The 180 motor is designed for up to 12V. If you go higher than 7.2V, then you wiill probably be best off going with my FET setup, with four cells powering the main electronics and the full battery setup powering the FET board.

Good luck finding a pinion that works, I have yet to find a satisfactory substitute.

[sinistar]

Neuro Good Work, I'm definetly going to be using this information on my project that is going to be next.

If you ever wanted to put any other type of any 1/24 1/25 scale body on your setup that would allow or should I say will allow more room for your fet setup along with the biggest motor and batteries setup let me know I have made 3 1/24 1/25 body fits for my Xmod and have had much room left. My first kit to fit which is being put through it's 3 week paint process was a Honda Civic Hatchback 2 in' 1 Revell kit. The second was a Eclipse Fast and Furious kit (Green eclipse by Revell). And my last completed fit was a 67 Ford Mustang Fastback which by the way had enough room in the back bumper area to fit at least two 9 volts stacked on top of each other and laying on their widest width up aginst the bottom of the trunk or mounted at this area. The motor area was incredible to you could even mount a set of lights up there and still have like a Mabuchi Re 280 or fatter. Lots of space all around and definately room for more batteries that is if you took out the stock batt holders.

At any rate though the point here is you can generate space by whatever fit you decide on here. The possibilities are endless but to narrow it down in a reasonable process would be to make whatever setup first and then decide on the body fit would be later or vise versa depending on how well versed one is with their project knowledge.

My Next body fit project after I have finished my Civic will be a Fujimi InitalD AE86 comic version 1/24 scale from HLJ.COM. The Trueno will be the end of all competitors as far as I'm concerned within miniz and xmods since I have mastered the Trueno (AE86 type I,J) and S.S. version(j) on GT3 it is a very good car and can drift perfectly with the proper tuning. And the theory behind this project is to make a sleeped out drifter of a trueno. Neuro Your FET upgrade seems to be the way I'm leaning towards right now as far as power goes. I'm trying to finish up my civic and still develope the newer drivetrain for the Trueno project I would like to be able to know just how the FET upgrade all looks and such without a body put on it to start to get an idea of how to start to build my trueno. The Drivetrain will comprise of either a stock rearend setup and a custom slavebox diff for the front with AWD capibilities or a Tamiya dual gear box for a rearend assembly and a very crazy all wheeldrive train rod connected to the custom diff slavebox. It's all possible and I'm going to do it. But I'm wanting to be shure first that I need to know and see your final design on your FETs so I can do the mod and make a very sick Xmod. Have you ever seen BTW while at RS the Tadiran AA 7.2V lithium Batt? very interesting supply there to make a setup.

thanks for your work Neurokinetik,
Sinistar

[xxspeednplayaxx]

wait neuro, your fet setup allows for a certain amount of voltage to the chip and the rest to the motor? do you have a regulator? could i still acomplish this by putting a 5v relay on my batteries (if they were 4x lipoly) as well as an internal fet upgrade?... im sorry for the confusion im really lost, i want to set up my car with 4x lipoly, and put a relay(or regulator not sure which1) to keep the chip safe, i also want to run the orion 180 motor reduced to 35 turns... can this be done? i was under the impression that all these motors could handle 18 volts

[neurokinetik]

Originally posted by xxspeednplayaxx
wait neuro, your fet setup allows for a certain amount of voltage to the chip and the rest to the motor? do you have a regulator? could i still acomplish this by putting a 5v relay on my batteries (if they were 4x lipoly) as well as an internal fet upgrade?... im sorry for the confusion im really lost, i want to set up my car with 4x lipoly, and put a relay(or regulator not sure which1) to keep the chip safe, i also want to run the orion 180 motor reduced to 35 turns... can this be done? i was under the impression that all these motors could handle 18 volts

The most recent setup that I posted connects the FETs directly from the batteries to the motor, with just the four wires run back to the main board for control. In theory (and this has not yet been tested) the FETs could be wired to a larger voltage while the board gets its normal 4.8V.

[xxspeednplayaxx]

so if you do this , do you remove the stock fets? im really sorry with all the questions but i plan to do some crazy modding next weekends (finished with finals) and im just trying to be sure with my aproach,


could you test your external fet setup? just add 1 additional battery and check the chips voltage... and the fets you used were the ir and il... how many volts can that handle.. as well as hpw many volts can the orion motor handle? or betr yet what torquey 180 size motor can handle 14.4 volts?? again sorry for the nub question and thnx for the quick responce

[scatmanjohn01]

the fet upgrade has NOTHING to do with voltage, it only allows you to run hotter motors. if you tried running 14.4 volts on only upgraded fets, it would pop in an instant. if you want to run more cells use jshwaas regulator mod or chinos relay mod.

[xxspeednplayaxx]

ok so let me see i if i have this straight...

1. all neuros fets mods are, are a simple way to relocate the upgraded fets, so that bigger ones can be used w/o any troubles under the car.

2. the fet mod in general allows you to use a more demanding motor, like in real cars, you must give a v8 more gas than a inline4, so the fet mod gives more fuel.

3. team orion stock motor under 7.2 volts dosent require a fet mod, but after 7.2 volts a fet mod should be in order.

4. in order to put an insane amount of volage in your xmod, you must follow either jshwaas regulator mod or chinos relay mod.
----------------------------------------------------------------------------
with this i have but three questions and then i wont bother anyone about fet/motors/voltage

1. by performing neuro's latest fet mod (the one that is said to run beter than the novac) could i use a plasma dask motor.

2. by performing the above fet mod, how will my xmods run time be affected?

3. by performing the regulator/relay mod ive heard that you loose you proportional control, is this true

and finaly id like to thank neurokinetic and scatmanjohn01 for putting up with me beging a nub and moron... thanx again

[scatmanjohn01]

no prob man.

I talked to jshwaa, and he said his regulator mod keeps digital proportion steering and speed. With Relay mod, you can only go forward or back at one speed, not sure if you can turn.
I' day anywhere over 8 volts, is where you wanna do jshwaa's mod. It looks like a hard process (and is hehe), but when im done with his mod it will be worth it.

About the plasma Dash, I am really not sure if it will work...
Chino, (who made the relay mod) says that his friend tried using a plasma dash on just upgraded fets, nothing else, and his fets popped in like 3 seconds after pushing throttle.

So, be careful what you do.

[neurokinetik]

Originally posted by xxspeednplayaxx
so if you do this , do you remove the stock fets? im really sorry with all the questions but i plan to do some crazy modding next weekends (finished with finals) and im just trying to be sure with my aproach,


could you test your external fet setup? just add 1 additional battery and check the chips voltage... and the fets you used were the ir and il... how many volts can that handle.. as well as hpw many volts can the orion motor handle? or betr yet what torquey 180 size motor can handle 14.4 volts?? again sorry for the nub question and thnx for the quick responce

With my mod, you do remove the stock FETs completely. The FETs can handle up to 55V, if memory serves. (The full specs are posted somewhere in this thread)

I did a little testing last night, not on the FET mod, but to see how the board handles six cells. It turns out that I was correct, and that there already is a zener diode on the board that keeps the voltage to the critical components at 5.3V, even though a higher voltage is being supplied to the board. It very likely that it is this zener diode that fries and causes receiver damage when too many cells are used. It would be really easy to upgrade this diode to one that can handle more power, and thus not require external regulators, etc.

I'll post more on this as I do more testing.


About the plasma Dash, I am really not sure if it will work...
Chino, (who made the relay mod) says that his friend tried using a plasma dash on just upgraded fets, nothing else, and his fets popped in like 3 seconds after pushing throttle.


Well, my setup fared much better than that, I actually ran the car around for about a minute before deciding that the Plasma Dash was unsuitable for XMods. It didn't fry my FETs, though they certainly got hot.

[xxspeednplayaxx]

is their any links furthering describing jshwaa's regulator mod?


and neuro, by installing a beefier zenner diode i can run more volts, just like that? interesting...

[TypeZer0]

interesting, just finished the chapter on diodes in my electronics class and i learned a lot about the zener diodes. a suitable but beefier zener diode would be one that handles more watts but maintains the 5.3 volts thus pushing more cells woudln't make the diode burn up so easily

[xxspeednplayaxx]

hmmm, pretty cool.. i was just reading up jshwaa's regulator mod
http://pub238.ezboard.com/fxmodrcfrm8.showMessage?topicID=512.topic
cept i dont get the schematic


p.s. hey neuro, i saw you giving me credit in that dumb forum about the new redline motor, thnx alot.. if your interested that 260 motor has 24 turns, i plan to beef up the motor with various techniques on this forum, however i still havent got the thing to sit flush, but once finals are over its xmods 24/7!

[scatmanjohn01]

Maqn someone needs to make a how to on removing fets.. its friggin hard to do (im practicing on a fried pcb) Neuro you up for it hehe?

[neurokinetik]

Originally posted by scatmanjohn01
Maqn someone needs to make a how to on removing fets.. its friggin hard to do (im practicing on a fried pcb) Neuro you up for it hehe?

I should have done it the other night when I did them on the Mini-z, but I was too excited about getting them in so I could try out a hot motor in it.
At least with the XMods board it is wide open around the FEts, which makes them much easier to take off and upgrade.

BTW, I was testing my FET setup tonight with the 21 turn double wound motor with Drac's magnets, and six cells. The biggest torture test yet. The result? The motor would get hot enough that I couldn't hold on to it, but the FETs were just barely warm, even after a couple solid minutes of free-running the motor.

Side note, I inadvertantly learned that a single AAA NiMH battery can supply around 8A of current. I was trying to check my batts to see how much charge they had left, and forgot that I still had the meter hooked up for current, not voltage. The AAA IC3's can supply almost 9A.

[scatmanjohn01]

shaweet.! lol.

Man i am gunna do jshwaa's regulator mod, but i dont know what batterys to use to get to 14.4 volts... hmmm any suggestions?

[spitty12]

I tested my IC3's at full charge and got 3.11 amps on a single cell which seems more reasonable then 9A, how sure are you that your testing equipment is accurate?

I'm using a digi multi meter I built(mostly soldered) from a kit.

[TypeZer0]

Originally posted by spitty12
I tested my IC3's at full charge and got 3.11 amps on a single cell which seems more reasonable then 9A, how sure are you that your testing equipment is accurate?

I'm using a digi multi meter I built(mostly soldered) from a kit.

well there you go, yours is a kit and his is a fluke unit (i think)

[neurokinetik]

Originally posted by TypeZer0
well there you go, yours is a kit and his is a fluke unit (i think)

It's actually one of the ~$100 Radio Shack units, but I was told that Fluke makes them.

[xxspeednplayaxx]

scatmanjohn01 : you could wire up 4X 3.6V lipoly, thats what i plan to do... allelectronics.com is your source


day 1 of finals is over!, 2 more to go :(

[spitty12]

Thanks, l'll have to disregard the ammeter readings then. Everything else has been accurate so far so I assumed all the functions were swell.

[scatmanjohn01]

Originally posted by xxspeednplayaxx
scatmanjohn01 : you could wire up 4X 3.6V lipoly, thats what i plan to do... allelectronics.com is your source


day 1 of finals is over!, 2 more to go :(

ok i was thinking that, but i would need to custom build a charger for them..

[xxspeednplayaxx]

no no, at all electronis they sell the 7.2 1200mah lipoly for $6.50 (youd need 2) and then they sell the corresponding charger for $4.50 (again 2) comes out to 22 bux, and with tax ans shipping no more than 30..

[charliebrown]

Originally posted by xxspeednplayaxx
no no, at all electronis they sell the 7.2 1200mah lipoly for $6.50 (youd need 2) and then they sell the corresponding charger for $4.50 (again 2) comes out to 22 bux, and with tax ans shipping no more than 30..

Actually 2 7.2 volt batteries will toast your car, butter side up! :D

One will do, and with the amperage, that SHOULD be plenty! :rolleyes:

Chuckster...

[xxspeednplayaxx]

not with a handly dandly regulator installed, it will allow for 5v to go to the chip, and the full 14.4 volts to the fets and motor :)

[scatmanjohn01]

Originally posted by xxspeednplayaxx
no no, at all electronis they sell the 7.2 1200mah lipoly for $6.50 (youd need 2) and then they sell the corresponding charger for $4.50 (again 2) comes out to 22 bux, and with tax ans shipping no more than 30..


yah i know that man, but if you buy those battery packs, your going to have to hook them up in serioes, and gunna have to mod your charger to charge those batts. Thecharger isnt made to charge 4 batterys, only 2, and even charging only two it cant charge 14.4 volts, it can only charge 7.2 volts..

So your'e going to have to mod the charger, or make yuour own.

[xxspeednplayaxx]

ill prolly wire it up so the i can use a quick connect to separate the batt packs, but any way i wanna keep the batts on the car and use a wire to charge, like the tyco r/cs hmm i have 2 ideticle r/c chargers that plug into the wall, would they work,

p.s. while im posting, dear neuro, i ordered the ir/il fets from some site and they should be in soon, im also gunna get a regulator from my r.s. (for future mods :) ) in your opinion what would be the best motor to throw in the get the most out of your fet mod? not to be picky but im only interested in 180-260 size motors, also how do you double twist? sounds interesting given your current draw tests.

heres a blunt motor winding question, i know that to wind a 30 turn motor you loop the wire around each individual arm 30 times, then move to the next arm...what if you did one loop on each arm, and go around the motor 30 times?? what would the result be like? im willing to try this as soon as i finish with these darn finals

[keeperman13]

alright, nice job. now i have a question for ya guys, where can i possibly buy these fets to do the same mod for myself.
I am very experienced with theiron and am pretty damn good at it. i would preferabley like to get the 4562 fets everyone is talking about, if theres anything better that i can get in its place that would be good too.

thanks guys.

[neurokinetik]

Originally posted by xxspeednplayaxx
in your opinion what would be the best motor to throw in the get the most out of your fet mod? not to be picky but im only interested in 180-260 size motors, also how do you double twist? sounds interesting given your current draw tests.

heres a blunt motor winding question, i know that to wind a 30 turn motor you loop the wire around each individual arm 30 times, then move to the next arm...what if you did one loop on each arm, and go around the motor 30 times?? what would the result be like? im willing to try this as soon as i finish with these darn finals

Best motor I've used so far is the 30 turn of 26Ga in a 180 can. But I have just started playing with the 260 motors, so stay tuned. For double winding, the best way is to use two spools of the same wire, and just wind two strands at a time around the poles.

To answer your second question, short answer: no, that would not work.

[xxspeednplayaxx]

neuro : thnx a bunch ill make sure to go down to r.s. to pick up some tinner, a regulator and the 28G like you said...

i also plan on making a stop at my local lhs, to pick up a team orion motor, as well as a 260 size motor (seeing as i broke the brushes on my current big bad motor while reinstalling the new 16turn armature) my only question would be : what is a good "hot" motor that i can stuff in, ill surely be looking for silver brushes and neo mags, but dose anyone have any sugestions? theirs a smart kid who works at my lhs but its usually his dim witted sister whos running the show (quite frankly i dont trust her opinion lol)

[scatmanjohn01]

what would having two strands of wire being wound do?

[Rez]

Neuro, Digikey lists several 4905 and 3705 products, each with various suffixes. I don't see any mention about which ones are "logic grade" and which ones aren't. Help me out?

[hostyle]

Ok, so after reading all these posts and thinking I have grasped all this, I have one question:

Neuro, do you remove each set of FET's on both sides of the board?

[Rez]

Originally posted by hostyle
Ok, so after reading all these posts and thinking I have grasped all this, I have one question:

Neuro, do you remove each set of FET's on both sides of the board?

I believe the FETs on the top of the board are for the steering servo.

[hostyle]

OIC, ok thanks

[b18ornothin]

im new to this stuff....i would really like to see how to upgrade fets so that i can run 6 cells, and a sb motor....and i want to do a wire upgrade...can some one tell me or post pics on how to make that work so i dont fry anything....if u want u can email me at MAKINMOVES84@AOL.COM

[hostyle]

If you take the time and read through this whole post, it goes into very deep detail, and give detailed schematics.

[xxspeednplayaxx]

fets - hard to explain, you buy the fets listed somewhere in this thread, and replace your current fets (found under the board) with two of each new fets.. another way is to do some fancy wireing (neuro explain on page 10-12 which give a super amount of current capacity..

6 cells (7.2V) - you buy a double aaa holder from the shack and wire it between the two batt packs found on the car (its the long black wire).. or you can buy two lipoly batts and get the same results

spinbrush - go to a store that sells toothbrushes, and get the spin brush tooth brush, beak it open and get its motor, pop the end cap off (white thingy with solder points) then pull out the armature (thingy in the center) then replace this with the armature from your S2 motors (you may wish to remove 5-10 windings (wires around the motor) any more than 10 and you wont accel good, then put on the s2 end cap... basicly the spinbrush motor has good magnets, and a good can, everything else should be from your s2 motor

wire upgrade - DONT BUY ONE THEIR A RIP OFF.. just go to the shack and get a spool of thick wire (not to thick) im not sure of the guage so just find a wire size you like.. all you have to do is one by one de solder your stock wires and replace with the wires you got...

happy modding!

[ninja828]

Originally posted by xxspeednplayaxx
wire upgrade - DONT BUY ONE THEIR A RIP OFF.. just go to the shack and get a spool of thick wire (not to thick) im not sure of the guage so just find a wire size you like.. all you have to do is one by one de solder your stock wires and replace with the wires you got...



and make sure its STRANDED wire, not solid...otherwise you'll have too much resistance in your wires and could ruin your xmod that way......i actually am still trying to solder on the 16 gauge wire i have as a replacement for the stock wires but im one hell of a hard time w/ that....maybe i need better quality solder....

oh, and does anyone know a good site to order the IRF4905 fets that DOESN'T require a credit card? i've already tried digikey, but they're backordered and i wouldn't be able to get them till march 4th....:mad:

[xxspeednplayaxx]

hold up standed is like many many little stands... wow thnx for telling me, i was gunna use 20 guage of the soldid core wire, its what i used for my lights.... hmm i have a bunch of 18 guage threaded wire that should work..

[geofroley]

Nuero what kind of FETs would you recommend for a 35 turn or lower application?

[neurokinetik]

Originally posted by geofroley
Nuero what kind of FETs would you recommend for a 35 turn or lower application?

Right now, there are only four options that I am aware of.

Option 1: Stack stock XMods FETs. We don't know what they can really do yet, but they do seem to be better than the stock Mini-Z FETs. Disadvantage: Limit of double stack before chassis modification needed.

Option 2: Stack IRF7389s. Proven chip, it works. Has the same disadvantage as stacking the stock FETs.

Option 3: Stack Sy4562s. Again, proven chips. Has the same disadvantage as stacking the stock FETs.

Option 4: Build my discrete FET setup. Handles more power than all but the biggest stacks, and the ability to add heatsinks to increase the power handling is another plus. A regulator could be added to the circuit which would allow for pretty much any battery combo you care to try, while keeping the stock electronics at a safe 5V. Disadvantages are finding a place to mount the board, and also routing the extra wiring.

In my Mini-Z, I am running a 3x2 stack of IRF7389s, and that is runnning a 35 turn motor with Neos. With that setup, the car is just too fast for the course I run it on. It is fun to watch, though, as I run around at about 20-30% throttle, staying with all my competitors until I feel like passing. Then a quick blip of the throttle sends me by them like they aren't even moving. :lol:

My discrete setup is only in my test chassis right now, as I want to see if I can shrink the board down even a little smaller than it is now.

[geofroley]

Hmmmm. . .Got a tutorial on your FET mod?

[ninja828]

just look at the previous pages. there should be more than enough info to build neuro's fet mod

[xxspeednplayaxx]

yup this thread seems to have a alota info (just gotta read)

[Doctoraudio]

Can you sell, the listed as #4, let me know!
I will send it buy Paypal
If so email me @ doctoraudio@msn.com

[neurokinetik]

Well, I only have one FET setup right now, so as of this time, the answer is no. After the beginning of March, when the IRF4905s come in from backorder, then possibly.

[neurokinetik]

On another note, I will be trying a new battery setup using as many as four 23A batteries (12V each) with this FET setup for drag racing. It has to be a drag only setup, because I doubt the batteries will last more than a minute. :lol: I already have a 5V regulator, so now I am just waiting for battery holders before I can try it. 48V and less weight than the stock AAAs should be pretty quick. (Quickest to blow out axles, blow up motors, etc. I just want to see what happens. It should be entertaining, at least.)

[Rez]

Are there no other good suppliers of the 4905?

[neurokinetik]

I just did a search and found this...

Apparently the IRF4905 is popular among the RC community for speed controllers...

http://www.oatleyelectronics.com/kits/k161B.html

Anyway, all the big suppliers I know (DigiKey, Mouser, MCM/Newark) are out of them at the moment, so we are basically waiting for International Rectifier to make some more. Newark actually has some, but they are the wrong package type, (we want TO220AB) so they won't work.

[xxspeednplayaxx]

dear neuro,

under my thread "regulator mod by jshwwa" could you post a tutorial of how you did it, theirs a lot of confused modders out their (myself included) who would like to know the details of this mod

also how would you wire up both the regulator mod, and your fet mod together? thanx a bunch...

happy modding!

[neurokinetik]

Well, the mod needs more testing. The 12V experiment (and hence any subsequent mods that use this type of battery) portion was a failure. These 23A batteries can't provide enough current to even get the motor to turn a single revolution. Even with a big capacitor to store the energy, the motor will only turn over a couple of times then stop.

Hooking up the regulator was simple. All I did was run power from the batteries to the input and ground on the regulator. Those same connections also go to the power and ground connections on the FET board. Next, I run a pair of wires from the output of the regulator and ground to the main board. The steering servo worked fine. The way it was hooked up. I was wondering if maybe the transistors were not turning on fully, thus not allowing the motor full power, but I confirmed on the scope that I was indeed getting full power, and even when I connected the battery directly to the motor, the performance was still just as poor.

[xxspeednplayaxx]

alrighty, that seems simple enough and your fet board is the diagram on page 9..

[codedat]

Neuro,
I've done some poking around and IRF has made a revision to the TO-220 packaged MOSFET you have used. I think it is now possible to shrink your design by 40%.

Check it out
IRL3705NS/L (http://www.irf.com/product-info/datasheets/data/irl3705ns.pdf)
IRF4905S/L (http://www.irf.com/product-info/datasheets/data/irf4905s.pdf)

Only a little difference between them in the Thermal Resistance.
Neuro check it out if you can I'm waiting for mine to come in. Feel free to comment if you found anything wrong with these Fet's.

THX ahead of tyme

[neurokinetik]

Originally posted by codedat
Neuro,
I've done some poking around and IRF has made a revision to the TO-220 packaged MOSFET you have used. I think it is now possible to shrink your design by 40%.


Power dissipation capability is quite a bit lower with these packages, however. 2W is actually lower than the S08 package is doing (3.5W) It is also much more difficult (if not impossible) to attach a heatsink to that package. I've had the tabs on TO220s get hot enough to melt solder, so I'd like the capability of attaching a heatsink.

Might be good for an "entry level" version of the circuit though.

[codedat]

Neuro, I'm confused? On their spec page it says 3.8W not 2W. Or is that just the calulations from using V from 4 AAA batteries. If so then shouldn't the original Mosfet package give you the same power disapation. (Whew I'm tired been up all night, can't stop thinking.)

[neurokinetik]

In one place it says 3.8W, but in the description at the top left, it says that package style is good for 2W. Either way, a smaller heatsink area means less power dissipation. They don't really make it clear whether the through-hole version is capable of more than the surface mount version, but the only real difference between the two is the way the legs are bent, so I wouldn't think there would be a difference.

[codedat]

Thanks for clearing that up :D I'm still finsihing up on my degree and some things are still not clear. I learned more in the forums from you then in class :)

[scatmanjohn01]

like this?

http://images2.deviantart.com/i/2004/07/f/4/circuit11.jpg

[neurokinetik]

Yeah, that's basically it, though technically, you don't need to show IC3 and IC4, and you should rotate the bottom side of the board so that the unconnected pins are at the top of the diagram.

[scatmanjohn01]

so there should only be 4 wires going to the external board from where the stock motor fets used to be?

[ninja828]

scatmanjohn01 posted
so there should only be 4 wires going to the external board from where the stock motor fets used to be?
yep, thats correct

hey neuro, how's the reg/fet combo mod progressing?

[scatmanjohn01]

another question, neuro, can i keep the stock fets on, and then just build a external fet mod and solder the correct wires to the correect stock fet pinS?

[codedat]

You can keep them on if you want. But there is the possibility of still buring up the stock fets because current still goes thru them. It's a 50/50 chance it will burn with it or not. Besides it is easier to solder with it off, and remove the aluminum heat sink at the bottom of the car to remove unwanted weight but keep the paper piece to keep most dirt off of the electronics inside.

My Two cents
Feel free to fill the bucket

[codedat]

Hopefully this should clear things up. Note connecting directly to the batteries is ok but don't forget to connect to the main PCB.
Here is a revised img

http://www.geocities.com/mastermind_sound_solutions/schematic.JPG

If the picture doesn't show click the link here (http://www.geocities.com/mastermind_sound_solutions/)

I belive this is what Neuro said it should be. Note directly connecting the battery is ok but remember that the main PCB needs power also.

I fix the link.

[ninja828]

..i dont see any pic and the link isnt workin....

[codedat]

Try again it will take you to home page then click on the link on the home page

[ninja828]

ahhh...ok i see it.....nice choice of colors...its like lookin at a rainbow...

[codedat]

Thanks

I tried to make it easier for people to see where the connections go.

[meteoraclown]

i was readin through this and decided to do this when i get some more money. Can someone make a step by step tutorial on this upgrade. I can't seem to find it. If i passed it will they post a link to it and tell what post # it is. thnkx cause i'm new to xmods and only had it for a month(still stock cause i got np money.

[ninja828]

....did you check out codedat's pic? his pic pretty much explains everything......just solder each wire depicted in the pic to the places shown and you'll be ok. IC5 and IC6 are the fets on the bottom of the pcb...but all the info you really need can be found in the previous pages....just take sum of your free time and read through the whole thing and you should have more than enough info

[meteoraclown]

ok thanks. i was readin this last night around 10 so i was tired.

[neurokinetik]

Just an FYI, IRF4905s are back in stock at Digikey, i got mine Monday.

[ninja828]

hehe...i just got mine...and im gonna be workin on combining the 5v reg and fet mod tonight........finally:rolleyes:

[charliebrown]

Originally posted by neurokinetik
Well, I now have the FET circuit hooked up this way. I thought it strange that LithiumXMod said that it didn't work, so I decided to try it myself. It actually does work, and now the only connections that need to go to the main board is the gates of all four MOSFETs. The rest of the connections are on the standalone PCB. Even a Plasma Dash wouldn't kill this setup now. Actually, even a Novak SPY can't handle the current that this setup can. :cool:

http://users.adelphia.net/~neurokinetik/schematic3.jpg

neurokinetik, TinyRC didn't give you 1/10th the reward you deserved when he made you a mod. THIS IS GREEEATT STUFF!!! I can't wait to get the FETs sooner or later....

Anyways, for some quick Q's: With your FET setup, the amperage limit is pretty high, from what I hear, so I'm thinking of getting the Team Orion Elite Stock 180 motor, and taking about 20-25 winds off the armature. It will have a bit of a high current draw, but I'm guessing the FETs you're using will be able to handle that. ;)

I'm thinking, that with your FET setup, I could possibly run a 15 wind 180 motor, and perhaps that will kick some serious "asphalt" or something like that. I can hardly wait to save enough money to get this little beauty running.....Thanks again!

Chuckster...

[codedat]

Got an e-mail Fri stating my order has been shipped :D
Hopefully I will be able to get going on the adjusted version. Neuro I will post how well it works. I know that the TO-263 packages have different heat Tol than TO-220 pk.

[neurokinetik]

Originally posted by charliebrown
Anyways, for some quick Q's: With your FET setup, the amperage limit is pretty high, from what I hear, so I'm thinking of getting the Team Orion Elite Stock 180 motor, and taking about 20-25 winds off the armature. It will have a bit of a high current draw, but I'm guessing the FETs you're using will be able to handle that. ;)


If you go that low, it won't have any torque at all. I've tried a 15 turn double, and even it isn't an acceptable performer, IMO. (It sure has great top end just spinning with no load on the bench, though.) It takes about 1 full second or more to spin up.

[meteoraclown]

Originally posted by codedat
Hopefully this should clear things up. Note connecting directly to the batteries is ok but don't forget to connect to the main PCB.
Here is a revised img

http://www.geocities.com/mastermind_sound_solutions/schematic.JPG

If the picture doesn't show click the link here (http://www.geocities.com/mastermind_sound_solutions/)

I belive this is what Neuro said it should be. Note directly connecting the battery is ok but remember that the main PCB needs power also.

I fix the link.

ok this is cool and all but which is ic5 and ic6. Is ic5 the left one and ic6 the right one or vise-versa

[codedat]

I re-labled them. sorry was in a rush on a quick revision. Recheck the link again.

[meteoraclown]

ok ty cause i'm kinda new to electronics and stuff.

[codedat]

No prob, glad to help. BTW check this out, it will help you on the basics of electronics.

Basic Electronics (http://tinyrc.com/forums/showthread.php?s=&threadid=18465)

[TypeZer0]

neuro, i breezed through most of this thread and i dont' think this was asked. does your FET upgrade board maintain the brake function?

[neurokinetik]

Yes. All original functionality is retained.

[geofroley]

Code I can't see your pic.

EDIT: Nevermind, saw the link.

[geofroley]

Does anyone know where I can get some colored wire from?

[geofroley]

Nuero, in your mod, where to we solder where it says + battery and - battery?

[TypeZer0]

go back a few pages and there are pics to show where to solder it

[killer]

Neuro! great work man!... have you tried using those big fets without the stock fets.. i mean you will remove the stock fets then repllace it with those FETS?.. just curious ;)

[geofroley]

Originally posted by TypeZer0
go back a few pages and there are pics to show where to solder it

Alright I found it, but is it on just on battery case?

By the way Nuero, what are the other FETs next to the IRF4905s in your pic?

[neurokinetik]

Originally posted by killer
Neuro! great work man!... have you tried using those big fets without the stock fets.. i mean you will remove the stock fets then repllace it with those FETS?.. just curious ;)

That was the way I was running it, yes. Stock FETs were removed completely.

Originally posted by geofroley
Alright I found it, but is it on just on battery case?

By the way Nuero, what are the other FETs next to the IRF4905s in your pic?

Yes, just run another set of wires from the battery cases.

The other FETs are the IRL3705N.

[eetoi]

I've ordered MY fets, I'm so excited...(One of them was backordered till April, I guess these things are in demand!) I tried a motor similar to the plasma dash, but made by auldey (only $1!) and when I put it in with a tamiya plastic gear and such, it seemed very weak, and took a while to get to top rpms(even under no load, I tried it out of the car), I'm assuming that after this mod, it will scream and accelerate better (It was uncontrollably fast in my mini4wd car, it BROKE a few parts of the car, I guess that's what digi-propo is for)... Am I right? And there's this OTHER motor, my cousin rewound (he's a mini4wd racer from the Philippines), and it took even longer to rev up.

[aperson]

i dont think this was asked yet but is this still proportional?

[geofroley]

Nuero, in your pic, does one wire go to one battery case, and the other go to the other one?

[Rez]

Originally posted by aperson
i dont think this was asked yet but is this still proportional?

Yes, it was asked, and it is.

[aperson]

oh sorry. i must have missed it.

[meteoraclown]

ok another question. where did you get the circuit board at? can i get them at a computer show or can i go retailers and get them?
almost there with the money. yay. i ha d the money before but had to pay back some money i borrowed.

[eetoi]

Originally posted by meteoraclown
ok another question. where did you get the circuit board at? can i get them at a computer show or can i go retailers and get them?
almost there with the money. yay. i ha d the money before but had to pay back some money i borrowed.

They sell circuit boards at Radioshack. Wow, they sell a lot of stuff at radioshack. Off topic, but, after I got my xmod, I started going to Radioshack a lot more often...

[meteoraclown]

ehh i don't think my RS is any good. the guy behind the counter didn't even know where the stuff was behind the counter on the wall. He didn't even know the difference between the S1 and S2 motors. i'lljustwait till i can go to the store where i got my car at.

[aperson]

eetoi, i'm only allowed to go to RS once a week since i got my XMOD. almost every night.

[eetoi]

aperson, that's about how often I get to go, wait, no, it's been like twice or thrice a week... now, why does it say; once a week, then, almost every night?