Killed 2 cars with 1 jump?

This morning I had to give my wife’s 2001 Park Avenue a jump because her battery is old. It is being replaced today.

After she left for work, I parked my 1998 Cherokee, turned it off, and packed for work. When I returned, the Jeep was dead-dead. I called a tech and got a jump. The Jeep started easily, ran great for 30 miles, about 35 minutes. The battery is dead again, really dead.

This battery is about 2 years old.

Do you think I could have killed the battery in the Jeep by jumping the Buick this morning?

I doubt that jumping starting the Park Avenue caused your problem. Either your battery just handed in its resignation, or your alternator isn’t recharging the battery in your Cherokee.

Is there a fusible link next to your battery? That was my first thought, but if that were burnt, I would not expect that the tech could have jump started it.

If the Jeep was running when you connected the jumper cables, it is possible that you may have toasted the alternator/regulator. However, that would not explain why the vehicle was dead minutes after the jump.

Nothing about jump starting SHOULD hurt a battery. There is a remote possibility of disturbing a connection at a battery clamp/cable that was poor already.

I am pretty sure that it is not the alternator. I have already put 2 alternators in this Jeep over the last several years. The most recent was a little less than 2 years ago, when I replaced the battery. When the alternator isn’t charging, I can see it on the gauge and a dash light comes on. (I learned that the hard way.) The gauge looked good this morning and the “dummy light” did not come on.

In addition, the Jeep won’t run very far without the alternator charging because it has to run on battery power alone, and I drove for a while this morning. By this process of elimination, I don’t think it’s the alternator or starter/solenoid. That only leaves the battery. Does anyone concur or am I way off? Is there something else it could be?

Any possibility that you loosened the battery clamp when you did the jump? Make sure the connections are clean and tight.

If the jeep’s battery was old and weak, and you did the jump without the jeep running, then this could have been the last straw for that battery.

Jeep was running before, during, and after the jump. Battery is 2 years old and until today, did not have any problems. Luckily, I have free replacement up to 36 months, so I am going to try that first.

Alternator diodes and rectifiers, fusible links, fuses, relays and voltage regulators are easy targets for damage in a jump start. Battery damage is very unlikely.

In principle, jump starting shouldn’t kill your battery. I’d take a careful look at the battery connectors and maybe the cables as well. Corrosion does build up between the battery and the battery cables and it can have enough resistance to prevent starting. Also, battery acid sometimes escapes and somehow ends up inside the insulation on one or both battery cables where it converts the copper wire to copper sulfate. It’s possible that one of your battery cables is half eaten away and only carries enough current to start the car when it is in the mood to do so.

Of course, it’s also possible that you did somehow damage the battery even though in principle you can’t.

I found out the problem!! Because I value the help I get here and because I care about our collective knowledge, here is the solution.

The shop that fixed my wifes car told her that one cell of the battery was completely dead, but the other half of it was still good.

I had my battery tested and they said that it could no longer hold a charge. Somehow, while the batteries where connected, the dead battery drew enough power from my battery, that it could not recharge again.

Luckily, my battery was still within it’s 3 year warranty, and I got one for free.