[cglrcng]

I did see that exact type of thing happen on our robot last year except not quite that far as they shut it off at the breaker. When the drive team came back from an early AM qualifying round, the student w/ the battery in his hands complained that I gave them a dead battery..."No way, no how" I said...as I checked it w/ a multi-meter myself I said just before handing it to him before the round.

I immed. began to inspect the battery Anderson clip Battery half (since it actually burned my hand during the semi-disgusted hand off) - and I saw melting of the clip & cables, and it was still very hot to the touch, so I took it apart and looked at the ends inside the clip...They were a bright orange copper color instead of alum. color.

I abruptly said...You do not have a battery problem folks..."You have a frame grounding problem," and pulled out the multi-meter from atop the battery cart and we began looking for the problem immediately. Sure enough, a frame grounding problem was immediately noted by a simple OHM check. That frame was grounded.

The hunt began....Sure enough, it took a while, but we found that (2 of the students had removed and reinstalled the CRIO the night before just before pit closing), and there was a nice short bright & shiny chromed Phillips Head screw near the bottom on the outside of the CRIO that was touching the lower chassis frame rail, that wasn't doing so the day before, (the CRIO's all come w/ that very unnecessary grounding screw), but, the CRIO is not supposed to be grounded to the frame in that manner at all. Same issue also cropped up w/ a grounded camera a few years back at champs that took a while to find.

Once that grounding issue to frame was cleared up...I have never seen that Anderson connector problem again. A simple ohm (00.00 meter read), check from battery to frame should tell you that you may just have the same exact problem I personally think.

I do know if they had not shut that robot power main breaker off very quickly, it could have been as bad as your pic or much, much worse. It did melt the outside insulation of the cables together right above the Anderson connector for about 2 inches (that was correctable as they pulled right apart and were still insulated properly, but those cable ends were junk), and melted slightly the connector itself...It was quite hot! That was very apparent.

Post back if you find it was a frame grounding issue please.