When a jumpstart goes wrong? Safety Question

Neighbor tried jumping my wife’s ‘06 Nissan Altima, we left it for 10 minutes and came back and the cables had melted through the headlight of both cars and some of the bumper. I wasn’t there but thankfully they stopped their car and were able to disconnect the cables without incident. We noticed after there had been mice living in around her engine from the mouse poop, minimum the last two weeks. What causes jumper cables to do this? Something a rodent may have chewed? Definitely an issue with my wife’s car. Our poor neighbors have a newish midsized suv. My wife has also had constant issues starting her car, even with a new battery I got a year or two ago. Anyone seen this before?

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u/Doenicke Dec 31 '23

I don't understand. Why would you leave it for 10 minutes, especially if the neighbour is such a handy guy?

Why not just start the car when you connected the cables? Then you would have noticed that i wouldn't work, since he put them on on the wrong terminals.

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u/Dorkamundo Dec 31 '23

I mean, sometimes when a battery is discharged fully it can take some time to build up enough amps to start it.

Especially if the cables are low-quality.

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u/Anxious__Engineer Dec 31 '23

It's taking the amps from the other car that's the point

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u/Dorkamundo Dec 31 '23

Yes, and if the cable is low quality, as in thinner cables, it can't provide enough amperage to do across that thin cable.

This also causes the wire to get hot from the large amount of current, which may explain the burn marks we're seeing.