Paul & Sabrina's cheap DIY 144v motor controller

[MPaulHolmes]

I'm glad you are OK. One time someone sent me a controller to fix, and I was about to grab the bus bars to pick it up, and just on a whim I checked the caps. It was like 120v or something! haha. Well, maybe it was only 70 or 80. I forgot, but 120 sounds better. This would work for a precharge lightbulb:

Battery Pack + ------- on/off switch --------- light bulb ---- Controller B+
Battery Pack negative -------------- controller B-.

Basically, before closing the main contactor, you just turn on that light switch. You can leave it on until you are done driving.

-Paul

[Gulah]

First of all I'm sorry for my poor English.
Second, I know there's a lot of work going on, and I shouldn't be talking about more options, but since there's a working DC controller, wouldn't it be great if there was a dual DC controller, what I mean is the removal of the differential.
And third, does the controller have regenerative braking? And does it have reverse? If it does, maybe it would be better to say that in the "Current Features" link.
Thanks in advance for your answer and all the great work done!

[flores]

Originally Posted by Gulah

And third, does the controller have regenerative braking? And does it have reverse?

No and no.. Reverse on a dc motor is difficult for a controller

[Crossdan]

Would a resistor work for discharging the caps after turning off the controller. Say a 100 ohm, 10 watt?
Wouldn't be as quick as a light bulb but it should still dissipate the energy as heat and drain them, right?

[jmcginley]

I use a 100 ohm resistor - it's a ceramic wirewound and probably more than 10 watts. In fact I have two of them and I put them in series. I have a 120 volt pack and the 100 ohm resistor raises a little spark; 200 ohms doesn't.

[Crossdan]

Thanks jmcginley. I'll get another 100 ohm, my current 100 ohm is also a ceramic wire wound.
Easier then adding a light bulb.
Dan

[mora]

I have my heater elements wired to controller terminals (B+ and B-) and if I turn controller off and heater on capacitor voltage goes to zero almost immediately. Main contactor open when controller shuts down. Otherwise it takes like one hour for caps to drain on their own.

[jmcginley]

Interesting, Mora. I took my controller apart a couple of years ago to put some nylon bushings in it, and it had been idle for a while, maybe a week or more. I got a big spark when I accidently bridged the B+ and B- with a wrench. I'm thinking the caps can hold a charge for a long time.

[mora]

Mine must be draining through DC/DC as it is connected to controller terminals too. At least I hope the resistance is there and not inside the controller. Simple test of disconnecting DC/DC and seeing what happens would tell me if DC/DC drains controller caps too. I wrapped all the bolts going through heatspreader with three layers of electricians tape even though the green power PCB doesn't have any copper near big holes anymore.

[MPaulHolmes]

I've ordered some parts finally to test the "1000amp" again. The 5 seconds at solder temperature approach to soldering the backs of the mosfets seems to work. Well, at least it is working well with the IGBTs in the AC controller. But I'm going to test 2 mosfets, 2 diodes at around 160 amps and if that works OK, then it's a go ahead to do 12 of each again. I really think it was the soldering method that messed things up last time.