9v batteries and zz's do mix - Page 3

Lestertech · #31 07-31-2003, 12:43 PM

i just tried it the motor and the pcb can take 9 volt i will get pictures soon

Lestertech · #32 08-01-2003, 10:49 AM

OK i hooked upi a 9 volt to a 1 gen pcb it had the blue gears and a speed motor when I strapped the 9 volt to the car I could tell it was tough on the car do to the weight. So i stripped out all the un necassary parts on the inside. And it helped the weight problem a little. I set it all up and let it go and it went as fast as a 3 gen pcb with the 34,000 rpm motor and red gears.

Steve · #33 08-01-2003, 08:27 PM

but wait, that's impossible! Hehehe..kidding. At least you settled things once and for all. Now take that damn 9volt off and add some bling bling...it goes a lot further.

ph2t · #34 08-02-2003, 06:16 PM

I'd just like to add my comments.

First of all I don't have any ZZ. I've got some ZZ pcb's care of some homies from da hood but that's about it. What generation they are I don't know but I've found out is the following.

First of all we have to look at how the 9V affects the pcb. The circuit can be divided into two parts, the rx/controller and the drive electronics.

The RX/controller part of the circuit is driven off what is called a DCDC Converter. In the case of the ZZ, this is the ME301 chip (search google for datasheet). The max it can take is 8V, the min is 0.8V. So any input voltage in the range of 0.8 -> 8V will always give you a 3V output that the RX/controller circuit drives on. ZZ and Bcg are very similar in this respect.

If you were to put 9V on this it could possibly work, but more than likely damage the ME301 DCDC convertor because it is 1V out of spec. This can have mixed results though. I've used many DCDC converters to get many different circuits going (indicator lights, headlights, knight rider lights, all you guys have seen 'em) and depending on the tolerance of these converters, sometimes you CAN put more voltage though them than what is specified. My bet is to go with the ME301 not working though.

The drive electronics is another story. I've got a circuit that will help the analysis, I did this for my Custom MOSFET H-Bridge Project over at bitpimps.

First of all the ZZ board's I have show the resistors in the circuit (R15,R14) as 220 ohm, just to clear that up.

Putting 9V on the H-bridge increases the current like nothing else, why? 'Cause of good old ohms law V=I*R. In this case the resistance of the circuit doesn't change. The motor is the same motor, pre and post 9V. The transistors and two resistors are the same, pre and post 9V. So given that resistance DOESN'T change, something must change. Re-working te equation to I=V/R gives us the notion that for R not changing and V increasing (ie: from 1.2V to 9V) that means that I(current) MUST increase.

I've never put 9V to a pcb and never put 9V to a motor, cause my instincts say not to. But that's just me, Im a firm beliver in each to their own.

But, putting 9V to the pcb and pressing fwd/rev would probably blow one of the H-bridge transistors BEFORE it blows the motor. Azimov's right in the statement of a motor drawing more current under load with max current reached when the motor is seized. See the "New dual cell" thread in Bit Science, I've posted current measurements there to back this up.

Than again, I'd like to see some proof that this would work via video if someone could do it. Cause ultimately I could spew forward more crap like this post for ever in a day, but it mean's bugger all in the face of conclusive proof.

ph2t.

Azimov · #35 08-02-2003, 08:45 PM

I agree with all of this. After all ph2t has researched the guts of these things quite extensively. No one has posted a video to prove the claim that the PCB will handle this much power. His reasoning reflects my own in the tolerances of the components involved. I would say that at most it may work for a very short period of time until the switching transisters in the h-bridge overheat to the point of failure. But, I would bet the forward transister will pop almost immediately. All in all, it seems an unwise modification. You are pushing the electronics past safe limits in order to lug a battery around that outweighs the entire car by quite a bit. And no one has stepped forward to defend the mechanical claims made here. Nothing yet has convinced me to believe any of these claims.

Quote:

So i stripped out all the un necassary parts on the inside. And it helped the weight problem a little. I set it all up and let it go and it went as fast as a 3 gen pcb with the 34,000 rpm motor and red gears.

This one bothers me too. What are all those parts you cleaned out of there. As far as I know the only thing redundant in the setup you mention would be the stock battery. That's not much weight difference between it and that brick of a 9V. I doubt it performed as you say. Which makes me doubt that you actually did this. This is part of my problem with believing the original claims. The mechanical claims of strapping a 9V to the side combined with a huge motor in the back and raised an inch are far fetched at best. I've found that when some things don't seem right, then most likely all of the claims are bogus. At this point, I feel this is one of the most exagerated threads on the boards so far.

2fast2furious59 · #36 08-02-2003, 09:03 PM

all i have to say is you need to show us proof, you are trying to tell us that you put 9 volts through the motor, well ok fine but now you claim you put it through the pcb which in all means isn't meant to hold that much volts so it would probably fry after a little while, and putting it straight through your engine doesnt help out much because eventhough you have a bigger motor you still dont know if it can last long...a regular zip/bit motor should last liek 10 seconds or less directly putting 9volts through it(correct me if my time is wrong) but i dont even think you can drive teh car if you have a 9 volt battery taped to the side of your car...theres a thing called weight distribution and that 9 volt off the side of your car...would throw it way off balance and tip it to that side

Azimov · #37 08-05-2003, 03:56 AM

I just did a forum search and found 19 threads that mention a 9V battery. This one:
http://www.tinyrc.com/forums/showthr...8122&highlight
shows a post where 12 volts was pumped through a motor. The poster claims that the motors could take it and failed due to melting the endcap due to friction. The internal contacts were unharmed according to his observations. So, it looks like the motors may take 9 volts, at least for a short time. So, I retract my declarative statement on that. However, there is no post claiming the PCB can handle that voltage level. The post sited here even says that it won't take it. Though he did motor tests only using kit racer frames. So, I don't see any threads on this site supporting the PCB taking 9VDC. I'm not willing to sacrafice a perfectly good micro to prove it to myself, so I guess I'm stuck being skeptical. You could do this to a mosfet modded car though. They can handle the voltage. Well some fets can. This gives me concern for a video proving anything as well. A mosfetted car could do it (assuming the DC/DC converter is out of spec enough to take it). A car with a paper battery made from scans of a real 9V constructed in Photoshop would make a very convincing video as well. I suppose the only way to really prove it to oneself is to bite the bullet and hook one to a functioning stock car. I'm just not sure I'm willing to pay 20.00 for the proof

.

jevries · #38 08-07-2003, 08:25 AM

I'm a bullitbiter so to speak...For one I do not own a microracer I'm orientating over here for my lowrider modelcars scalling from 1/64 to 1/10 all hooked up with motors to do all the hop and move stuff. http://www.e-zone.nl/jevries
I fried 5 circuitboards ranging from 3V to 6V RC cars...
The 3V ones couldn't handle the 9V battery...well mabye for 20 sec than smoke came out of the car....not the motor but the circuitboard was fried.
The 6V RC handle the 9V battery well...but a 9,6 accupack fried the board because of the high amps.

I would love to believe these small and tiny circuit boards could handle a 9V battery...leading to a relay instead of a small motor but as stated before...where's the proof.
let me see someone pick a 9V battery hook it up to the connectors, taping it and letting the car run and steer..you would make my day since it opens lot's of doors for me.

Azimov · #39 08-07-2003, 07:36 PM

Well, I'm not willing to try it with any of my Zips. I have a couple of gutted clones that still have good PCBs in them and I may sacrifice one of them for the cause. I know they are close to a Zip in most ways. It may not be definative proof that a Zip would fry, but it would give a good idea. I may try it just for the heck of it.

charliebrown · #40 08-07-2003, 09:29 PM

[edit: moronic comment removed by me]

ph2t · #41 08-07-2003, 10:22 PM

Quote:

Originally posted by charliebrown Azimov and ph2t are wise persons and they went out of their way to show us what a lie you are telling us![/b]

I didn't "go out of my way" to discredit the original claim. I just stated what I knew and any mathematical proof I could find for MY reasoning. If you read my statement you will notice that I ALSO said that in the face of actual proof I'm willing to believe this could be done.

Dude you to chill, who the hell cares anyway......

ph2t.