Paul & Sabrina's cheap DIY 144v motor controller - Page 523 - Fuel Economy, Hypermiling, EcoModding News and Forum

MPaulHolmes · 11-29-2011, 02:36 AM

There should actually be about 1kOhm resistance from Gate to source, but drain to source should be large. I would disconnect the bus bars from the battery pack and turn on 12v to the control board, withe the throttle connected. Then I'd check the voltage from any of GR1 through GR10(either side) to the B- bus bar. It should be zero volts. Then with the volt meter still attached, I'd give it a little throttle. The voltage should climb to about 12v, and then drop to zero, and the led should start flashing. Does that happen?

amino · 11-29-2011, 03:16 AM

Paul, I will reconnect the controller board to the power board and test the voltage between GR1 thru GR10 and B-. I am getting 3.34M Ohms from drain to source and over the 20 meg scale at gate to source.

Amin

amino · 11-29-2011, 04:28 AM

Well, I put the controller together again and checked the voltage from the gate resistors to B-, and it rose from zero up to about 12 volts before dropping back to zero as the LED started flashing. Connected a 12 volt lamp to M- and M+B+(with a second 12 volt battery) and it went brighter as I turned the 5K pot.

I will try it in the car again tomorrow and see what happens.

MPaulHolmes · 11-29-2011, 10:06 AM

Is the DC-DC in the car isolated from input to output? Do you know what sort of isolation rating it has? There isn't a chance that the battery pack ground is shared with the control board ground is there?

amino · 11-29-2011, 01:40 PM

The DC to DC converter is isolated from input to output, but I have no information on the isolation rating -- it's a Kelly 96V to 13.5V, and is switched into the circuit with th same solid state relay as the precharge bulb. The battery pack is not grounded with this setup --only connected to B- and DC/DC negative plus the heater 'negative' as shown in the diagram I attached previously.

amino · 11-29-2011, 07:46 PM

Paul,

I installed the reassembled controller in the Chevy Sprint and did some tests before making all the connections. With just the pack B+ and B- connected, I switched on the relay to precharge, and this time the bulb went on and no more smoke from the vicinity of the controller. With a 7 watt bulb the precharge time was 25 to 30 seconds, so I replaced it with a 40 watt one and that cut it down to about 6 seconds. I had set the controller precharge time at 7 seconds, so this was perfect.

Completed all the connections, checked and rechecked them and then switched it on. The precharge bulb came on, dimmed off and I heard the contactor close. Pressed the throttle pedal and heard the motor rev up genlty. As the front wheels were raised up off the floor on stands, I put it in gear and ran it a little and it seemed to run fine.

I'll do a test drive after I tighten all the connector bolts and nuts.

Amin

MPaulHolmes · 11-29-2011, 09:57 PM

That was mysterious! Oh please don't blow up... That sucker looks beautiful. How did you do the end caps?

amino · 11-29-2011, 10:34 PM

I had the rear connector cover panel from a 37" ViewSonic TV which happened to be about the same height, so I cut a piece from each end the width of the case and filed the edges to fit. Since it is a fairly soft ABS plastic, I was able to shape the rectangular holes with an exacto knife after drilling small holes around the outline. They are not yet glued in -- just held together by being pressed on with zip ties on the bus bars. I also shortened the case cover and the M- bus bar by an inch. Used an old table saw with a metal cutting disc in place of the blade -- works on plastic too! I had managed to get the current sensor closer to the circuit board by cutting the steel bar short so it would slide over the insulator board.

The smoke was probably not from the controller. I suspect a momentary short circuit across one of the 12 volt wires near the back of the controller, although I could not find any trace of a burnt wire anywhere -- probably vaporized.

MPaulHolmes · 11-29-2011, 10:45 PM

Very nice work.

BlueBlood · 11-30-2011, 01:51 PM

Great work guys! I'm building an 88' toyota pickup, has no motor, so i would rather spend the money to convert it to electric (inexpensive as possible, of course) than put an ICE back in. I have a good supply of batteries and this controller will work well for me.

I've been reading from page 1, after about four days of reading i'm only at page 101! I know I have a long way to go, but i'm the type of person that needs the back story.

Thanks to all of you for the work that has been put into this.