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Blew pack fuses on ignition. Curtis 1238se controller and AC-50 motor help

1587 Views 11 Replies 7 Participants Last post by  Russco
Sort of a huge disappointment, but after wiring up my whole conversion verifying the wiring and turning the ignition I blew the pack fuses and my worry is that I fried the controller.

I wired up my system matching the attached EV West schematic, I've got the AC-50 motor with the 1238SE-7971 controller.

I've got 5 Tesla Modules wired in series, they're divided into three battery boxes, two boxes each with two modules wired in series with those two boxes each containing one 150 V 600 amp fuse on the negative lead coming out of the box. Then the final battery has its own 150 V 600 amp fuse on the negative line, which is the pack most negative lead.

When I turned the ignition for the first time I heard a big click. I thought this was the contactor, but discovered the controller didn't light up, or turn on. I discovered that the fuse between the negative most battery terminal and the shunt had blown. I wasn't sure if it was perhaps a bad fuse, or what, so I thought I could perhaps test to see if it was by bypassing that last fuse and try again without touching the throttle or anything. I did that, and ended up blowing the two other fuses apparently?

Definitely a bit unsettling, as I checked all my HV wiring against the schematic. I measured resistance of the main contactor after the event (with batteries disconnected) and it looks like the contactor is still open so I'd imagine that wasn't the issue? I also checked resistance across B+ and B- on the Curtis controller and there was no resistance, but I'm not sure there is supposed to be. I checked to make sure that my KSI was still functioning correctly and it seems to be.

Where/what would you start to diagnose next? My fear is that I not only fried three $100 fuses but also a $2k+ controller.

Product Schematic Font Rectangle Parallel
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i would make 2 schematics, one for the HV stuff and one for the LV stuff. That single diagram is too confusing.

i don't see a precharge contactor, so i bet that the fuses blew from the huge inrush to capacitors in the charger, inverter and DC Converter. A capacitor looks like a short at turn-on.

i don't see a contactor on the HV(-) side to isolate the pack when all power if off.

Using a voltmeter check to see if you have any HV leakage to chassis. Measure from HV(-) to chassis and also from HV(+) to chassis. Is the DCDC an isolated converter?
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