Electrical nightmare

Ok guys, maybe I am a newb but I can take care of most of the problems with my 00 xj that arise...

so here is the deal... about once a year, I will drive and everything starts and runs normally.. then out of nowhere the next start... perhaps only a couple minutes later I turn the key.. get a big click and everything is totally dead.. battery COMPLETELY discharged, then I took my boat battery from the back to try and jump myself... and it ate that battery too! and now neither battery will take a charge after.. and now.. same problem.. wont start with a jump for about 3-5 minutes then will and then it dies like the f-ing idle is set too low... so werid.. ever heard of this before? the battery is only 8 mo. old and the alternator and starter are good...

Do you still have the original wiring. Your oem cables and especially the grounds are bound to be very corroded by now.

I would first look at the cables to see how they look. If there is any corrosion them replace. Next thing I would check is the starter. It sounds like there might be a dead short in it. A short like that will kill a battery fast. The not wanting to idle is a normal thing after a low voltage situation. To get it to relearn the idle you need to hold your foot down on the gas to keep it running, and then put it in gear. I let it move just a bit too (like just a foot), but I'm not sure if it is necessary.

but would it kill a battery and make it not take a charge? what does that, I put a brand new battery in it, ran it for a couple days like normal and today SAME THING! why does it eat the battery and make it dead permanently... I tried to charge it and it is just DEAD.

Yes it could.

[FONT=Tahoma,Arial]If a shorted battery cell does not clear the external short, the electrical connection between the battery terminals allows for a very rapid chemical reaction as the sulfuric acid converts the lead and lead dioxide to lead sulfate. Now the electrical energy is not dissipated externally, but internally in the form of heat. The resulting temperature rise inside the battery cell literally destroys the cell and actually may vaporize the battery materials including the electrolyte and lead.[/FONT]

wow so yes then... thanks, good thing it was a wal-mart battery, guess I will find the short and get that replaced.. so... if I am eating batteries its a short... not corrosion right?

Any service manual factory or not will glide you through a good over all starting/charging system check. Nit picking through one part then another will end up being confusing and time consuming.

badron said:

Any service manual factory or not will glide you through a good over all starting/charging system check. Nit picking through one part then another will end up being confusing and time consuming.

Click to expand...

X2 I would pull the starter, and take it to have it checked. Have them do the test several times. If they find nothing you could go to a car audio shop, and get one of those high amprage inline fuses to put on it. That way if it really is the starter it will just blow the fuse, and not kill the battery.

thanks guys, starter checked out fine after making the guy test it 10 times, I will now replace all my mains since I have the kit sitting here already, and hopefully I find a really bad uninsulated cable in there somewhere... I'll be back if I need it! and thanks to wal-mart for exchanging batteries I obviously f-ed up myself!