Electricity and car quick question.

[fitz19d]

On a semi newer car. For a jump, and if you were to put the leads on backwards from a charge pack. Aside from the ensuing shower of sparks, would that conceivably blow the entire engine/electrical system?

Had a customer have a battery jump twice and basically concluded that it was bad alternator as it'd die after it was in gear and started to go. Now a week some later they are trying to claim the jump was bad and blew the whole thing. (Vehicle was left running, but gas not revving engine and headlights dim and them calling a tow truck.) Didn't have swapped cables, but I'm trying to shoot down that claim since otherwise it's more of a he said she said.

[sniper7]

There should be a main fuse that protects the electrical system from the battery.
The high current will probably damage the batteries, maybe not making them unusable but internal damage could occur.
The jumper cables could be damaged as it could heat them up quick and melt the insulation/rubber.
The alternator in the charged battery vehicle if it was left running could be damaged as well.
The polarity would be reversed as well which on the dead battery vehicle could damage the sensitive electronic components like the computer or some sensors. I would think that fuse would help protect this though.

It is possible, but I would hope if you do this on a fair occasion you could say it isn't your first rodeo and made sure they were correct.

the best way to try first is disconnect the battery on the good vehicle and hook that up to the dead vehicle. then you only risk your battery and not the good vehicles systems

[Wulf202]

It's possible to have fried components or a component but it wouldn't fry the entire system.

[Wulf202]

The main fuse would be on the wrong side if the cables were connected backwards so it wouldn't come into play

[tmleadr03]

There is a very good possibility it fried computers. Modern cars are very sensitive to voltage spikes and reversing the leads can lead to very bad things.

On Euro cars I tell my customers to just have it towed if the battery is dead unless it is an emergency. I have seen multiple dead computers from jumping euro cars.

[fitz19d]

Want to say like a honda or something. 4 banger. Been a week already hazy as it was run of the mill other than the car not running right.

@wulf. Was a small portable charge pack not a vehicle to vehicle.

[davsel]

I did this once.
Used the wife's 1999 Audi to jump my 2002 F150 - had the cables backwards.
Sparked really nicely, but it only blew two small fuses in the fuse box - accessory, and interior lights - if I remember correctly.
Truck ran fine otherwise.

Don't drink and jump!

[J]

Most of the jump pack units have circuitry to disallow current flow if they are on backwards. See if yours has this.

[rockhound]

Roomate in college did this to his 87 celica, car caught fire

[JMBD2112]

Most American vehicles have a 150-200 amp maxi fuse that will blow, doesn't sound like it in this case. I had one a while back with the same problem that popped the maxi fuse and fried the fusible link before the alternator. Once I got the maxi fuse in, no charge from the alternator, after some digging I found a burned spot on the link, you might want to check that.