# Curtis PMC 1268 reverse Polarity PRotection?



## Superyellow (Dec 8, 2012)

Hi I made a terrible mistake I was feeling dum dum today and I wire the controller reverse and the terminals sparked and burned the fuse on fuse sense wire on my EV project. everything was wired and I didn't see any damage to the controller from outside and it smells ok however when I try to turn it on no light comes on and the reverse alarm makes usual static noise. can someone please tell me whether it has reverse Polarity protection or not. I feel like an idiot any advice would be useful thanks


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## Tesseract (Sep 27, 2008)

TL;DR version: Sorry, you cooked its goose but good. Get another controller, as it won't be cost-effective to repair this one.

Longer version: When you connect the battery pack to a controller in reverse this forward biases the freewwheeling diode and the anti-parallel diode across the switch, which results in near-short-circuit current flowing through both of them. Sometimes the controller will survive this abuse, especially if the pack voltage is low and/or its impedance is high, but another issue here is that almost all lower-voltage controllers (ie - rated for 96V nominal or less) also run their control circuits off the traction battery, so its likely those were damaged in your '1268 as well.


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## Superyellow (Dec 8, 2012)

I opened the controller I had a feeling that you were gonna tell me the bad news. I cannot see any fried component but it smells slightly fried electronics. I cannot buy another controller due to problems with customs. so I got two options
A) run the sepex motor with a contactor and 12V + 36V battery pack without a controller
B) try to replace the fried components.
what am I looking for here? It's almost impossible to see any fried component. some capacitors have slight grease on them but that's all


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