Paul & Sabrina's cheap DIY 144v motor controller

[jyanof]

Ticked over 6000 mi on the controller last week (9000 on the car)! The controller has performed flawlessly so far this summer, even on the hottest of days.

Paul, remember I was having issues last summer with the micro locking up under acceleration when it was hot outside? That's completely gone now. In fact, everything is working so well that I forgot to look for it, but it definitely hasn't happened yet this summer.

The only change we made was adding those little diodes to the bottom of the board. I don't think anyone else has had this problem, but if it ever happens again, I think the diodes are a good solution.

[MPaulHolmes]

That's awesome Joe!!! The latchup could also have been caused by a stupid line of code that I had in there. It was if throttle was less than a certain value that was out of range, then enter an infinite loop. Fran looked at that part, and said "Paul, check out line xxx". I then said "Is that what's causing the latchup?" Then he said "ya, maybe..." But also the lack of diodes could have been the cause too, but we fixed the software problem as well. Now the throttle has to be out of range for like 0.1 seconds before it causes an error.

[jyanof]

ah, that's right! I forgot about that, but I remember now. I guess I could check to see if removing the diodes do anything, but that sounds like a pita. I'll just leave them.

[apowers]

Maybe it is just the way the potetiometer is ajusted and the throttle is not moving far enough. I adjust mine by hand till just before high pedal error.

[Dwffy]

Hey you guys,
Your input has been awesome. I really appreciate your help. Problem solved. 1st there was a loose connection and secondly the pot was not giving full throttle. I fitted an ammeter and I tried driving using a 5k pot and turning it by hand. Man this controller is just great. Pulls 350 amps and nearly lifts the front wheels off the ground.. That was with 60volts. Now I must try it with the full 120volts. I will keep in touch. I now need to tidy up the wiring and put everything in its right place. That will keep me occupied for a while yet. \ Once again, thanks to all for your help.
Doug.

[Dwffy]

Paul,
You mentioned in your last post that I might need a newer chip with an updated program. Do you still think that is necessary? If so, could you send me one and let me know how much I need to send etc..
God bless,
Doug.

[MPaulHolmes]

Hi doug! sure we will send you a chip.

[Dwffy]

Hi Paul,
Don't be too hasty in sending me that chip. I will be needing some other parts first, see attached pics. I tried the controller on 120volts to see what it could do, and, I found out what it can do. I started off at 60 Volts and went up 12volts at a time until reaching 108 volts. I had the vehicle in neutral and each time I uncreased the voltage I would blip the accelerator and watch the ammeter and listen to see if the motor was spinning. All went well up to 108 volts and since I had the vehicle in the back alley whilst working on it, I conneted the final battery and jumped into the drivers seat ready to take off in my new wonder machine. I blipped the accelerator and the ammeter shot up really high for a few seconds as the vehicle started to move then it went down to zero. I took my foot off the accelerator and heard the cut-out disengage the batteries and then accelerated again to about 1/2 throttle. There was a huge bang, something like a 45 firing inside the engine compartment and everything ground to a halt. All the smoke in every semiconductor on the planet let out its smoke today in my poor little pickup.
see pics attached.
I guess it's back to the drawing board again. Any feed back will be welcome.

[MPaulHolmes]

Oh man, that's not good.

You hit the accelerator, and the ammeter went really high for a few seconds, but nothing blew up? So, when you took your foot off the throttle, you have a contactor that opens? That must be what kept it from blowing up. My guess is that at least 1 mosfet failed shorted when you hit the throttle, but the legs didn't have a chance to blow up because you opened the contactor soon enough. Then the next time you hit the throttle, since at least one mosfet was failed shorted (it looks like all were failed shorted), it was like a short circuit across 120v, so thousands of amps all at once, which would vaporise the legs. But why would 120v cause the mosfets to fail?

You had said there was a loose connection before. What was that? Was it one of the solder joints? If the front end was almost lifting up at 60 volts, that didn't sound right either. It should have been smooth acceleration. I wonder if there was a problem even at the lower voltage. Was there any time that the 12v battery shared a ground with the full pack voltage?

The hardware overcurrent protection wasn't working I think because the mosfets had failed already, so it wouldn't have mattered if the mosfet driver was disabled.

Does anyone have any ideas as to what could cause this? Ben had problems with his controller from moisture. He ended up baking the control board and sealing it in really well. It was quite a while ago that you got it. Could it have gotten some moisture in it sitting out in bad weather for several months do you think? I'm just making stupid guesses at this point.

Maybe I did a bad solder joint somewhere. It was one of the first few I made, before I learned to solder very well. Even now I'm still not very good.

[MPaulHolmes]

Oh, which of the gate resistors are fried? That's sometimes an indication of which mosfet failed shorted. Actually, from the picture it looks like all of the mosfets failed shorted. All the source legs are blown off, which is a tell-tale sign of that (leg #3 counting from left to right)

How do the diodes look? (the ones on the side opposite the picture)

How about the capacitors?

Can you take pictures of the gate resistors and control board top?