A few weeks ago, I mentioned that one of the wires in my EV was getting hot enough to burn the coroplast terminal covers. This week I fixed it, despite being sicker than the dickens.
The DIY Electric Car Forums recommended measuring the resistance of the wire by measuring the voltage drop at a known current, so I turned on my high beams and heater, and cranked the stereo. I managed to pull a reasonably constant 14.6 amps. The hot wire showed a 0.22V drop; the next most resistant wire showed only 0.02V, while most showed 0.01V.
I didn't see any obvious problems with the wire when I took everything apart. Every problem I saw could have been caused by the heat, rather than causing the heat. I'm guessing the problem was a bad connection because the wire was bent too severely: it was a 3.5" wire in a 3.25" space. That made a rather spectacular bend.
I cut the new wire to 3.05" (drat!), so its bend is almost unnoticeable, but it's still tight. In case the regulator leads were causing the problem, I moved them, too. Originally I just stuffed them in the clamp with the traction cable, but this time I attached them to a screw instead.
The new wire has a 0.00V drop at 14.7 amps. Everything else is still in the 0.01V to 0.02V range. Nothing's getting hot any more. And the car made the morning trip almost 2V higher than usual! I'm so pleased!