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

1582 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.

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I'd bet there's an error in your wiring!

It could be one of your contactors is actually shorting the pack for example.

I would break it down int bits. Disconnect the power going into the controller, DCDC converter and Charger & replace the pack fuses with some much smaller ones (10A say). Then try turning on the ignition. If one or more fuses blow, you have an issue somewhere in the wiring.

If the fuses don't blow, connect one of the components you've disconnected & re-try. That will enable you to find roughly where the problem lies.

Make sure the polarity of the power going in to each component is correct - particularly the controller. If it's connected backwards, it will present a dead short. Reversing the polarity will probably bust it - but you never know!
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