upgraded FETs

[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. 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...?&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.

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

[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)