Four months ago I stopped my '89 jeep cherokee while running an errand and when I went to turn it on again it was completely dead... wouldn't even honk. Had the alternator checked and finally determined that the battery was beyond hope of keeping a charge (even though it was only 1 year old and had a 6 year warranty). So I replaced it with a new one.

Today, the exact same scenario is happening. After a long 4 hour drive I came home turned off the jeep for 5 min while unpacking and it's completely dead (well, this time my head lights would still come on but no start or even turn over). Had a garage give it a charge and let it run for 40 min before shutting it off. I immediately tried to restart it and it wouldn't turn over again!

I'm starting to wonder if it isn't something electrical that is quickly draining the Jeep at random. Hummm.... any ideas?

Did you check the charging rate at your battery with a meter and the motor running. Should be 14.3 or close to that running. 12.6 or so with it not running. That way you can see if your alt is charging to high or to low. Might be burning batts up or not putting in enough charge. They do sell bad new or rebuilt alts. So check them volts out.

I double checked the testing report from when I took out the alternator and had it tested at Kragan's Auto and it was properly charging then. This was done when I first thought it was the alternator and before I bought the second new battary.

The biggest problem I see with batteries is terminal corrosion. If the power that alternator is generating isn't making it into the battery, it certainly doesn't stand a chance of making it back out when you need it.
Have you tried load testing the battery? It would be a good indicator of it's capacity and state of charge. Are all connections involved (And I mean all of them, all feeds, all grounds) clean and tight? It sounds too simple but I've seen it before...The alternator and battery changed out for what turned out to be dirty, loose battery terminals...(Yes, get the clamp or connector down to bare metal and the terminal on the battery down to bare metal too...Don't let that black shiny stuff you think is bare metal fool you, it's a cruddy conductor)

Stephen

depending on the age, and driving conditions. its likely that you will need some battery cables..... I like to put new ones on vehicles i buy if they haven't been replaced. then i know what i'm dealing with.

I went out and filed down the cables and the terminals like you suggested and hooked everything back up. Went to start the car and no start...but I realized something....
It does not even attempt to turn over. You don't even hear it try. The gauges jump (battery, oil, etc.) but it doesn't not even click. The horn and lights work. (don't have a radio at the moment)

Does this mean it's the starter?

Neutral safety switch:
http://jeepin.com/features/nss/index.asp

sounds like you may have a starter problem . may be shorting . check the cables and the wires to the starter


good luck

Had a similar challenge. Batteries would last about 9 months to a year. Checked my electrical for a voltage drain on the interior lighting circuit. Found it was somewhat higher than specs, but not alarming. Removed the fuse and solved the problem. Next battery has been fine, 4yrs later... No interior light or remote door lock but the battery is fine!

I had a similar problem with mine...first thought it was the battery, then thought i t was the alternator...still had the problem. It turned out to be a large fuse under the hood, I guess in one of the boxes there. My mechanic found the problem and replaced the fuse for me, so I'm not sure exactly what it was. Anyhow, it turned out the money on the alternator at least was wasted, when a cheap fuse was the problem.

could be starter relay, or starter, or nss, could even be the ignition switch, check for power at the starter relay (SOL) terminal to see if there is battery power when the key is in the start position.