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

1585 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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You should have placed a 100 watt regular old household light bulb in series with any battery lead. When the contactor closes, the light should go out. If the light stays on, something is wrong.

This way, you won't harm anything if something is wrong.

Old startup procedure for any new conversion.
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