Very doubtful they did anything wrong. To be overcharging is the fault of the voltage regulator, (or the wire going to it is grounded), and the regulator lives inside the Engine Computer. That circuit causes very little trouble.
Connecting jumper cables backward can do a lot of damage, and we read about it here every day, but it is unlikely the only problem would be with the voltage regulator circuitry. That is the last thing in the computer that would be hit. The alternator is the first thing because they all have at least six diodes which are one-way valves for electricity. They are in the circuit backward so they prevent the battery from discharging when the engine is off. Connecting jumper cables backward "forward biases" those diodes which turns them on, and in effect, turns them into a piece of wire. There will be nothing to limit current to safe level so those diodes will short instantly or a large fuse going to it will blow. On older vehicles that fuse was a special wire in the harness that was thinner to make it the weak link in the chain, and it had a special insulation that would not melt or burn. On newer vehicles that is usually a large fuse bolted into the under-hood fuse box.
Computers and the radio have diodes inside them also to prevent damage from reverse polarity. Those diodes are between the power and ground wires but are also installed backward. They don't do anything when the battery is connected properly. When the battery cables are reversed, those diodes turn on and draw high current forcing the respective fuses to blow. That saves the computer.
Your vehicle has a Central Timer Module that turns off unused lights after 15 minutes so the battery shouldn't have run down. Due to all the computer memory circuits, there is a constant small drain that will run it down over time but 12 days shouldn't have done it. Unless the manufacturer specifies differently, 35 milliamps, (.035 amps), is the accepted standard value, and at that rate, Chrysler says a good battery will crank the engine well enough to start after sitting for three weeks. If your battery is older, it might not hold out for 12 days, but if a jump-start was needed, I suspect you would see multiple other problems if the cables were reversed.
SPONSORED LINKS
Friday, November 30th, 2012 AT 3:46 AM