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Battery woes

552 views 5 replies 6 participants last post by  Jerry Bransford 
#1 ·
I've got battery issues. It's dying overnight. Something is killing it and can't figure what. I posted in the electrical section, but quite honestly, that section is dominated by stereo talk and I need a bigger audience from the general TJ guys. Here's the link to my post if anyone can lend an idea:

https://www.jeepforum.com/forum/f20/battery-won-t-hold-charge-4364097/

Thanks
 
#2 ·
Not holding a charge is a sign of a bad battery. A proper load test should confirm that. A good battery will not die overnight & the 30 mA draw is within the factory spec.

The draw from opening the door has nothing to do with it dying overnight since the door is closed so don't be concerned with that. And since the lights dim down as they time out & go off completely that fluctuation may be normal for a few seconds.

From my FSM:

A normal vehicle electrical system will draw from five
to thirty-five milliamperes…
 
#4 ·
Start by charging your battery then do a load test on it. Drive your jeep like you do. Then at the end of the day disconnect the battery. The next morning connect the battery and try to start it. This will give you an Idea how the battery is. if the battery passes then look for a drain. you never said how old the battery was. is the jeep dead or does it make noise when you try to start it ? do the head lights work but it will not start ?
 
#5 ·
If the battery is charged, only two things can discharge it. One is an external load. You can easily test for this as described by yelrdog. Second is the battery's internal resistance. You can't do anything about that.
My guess is that you have a faulty battery.


When you resolve this, please post the solution.
Thanks.
 
#6 ·
Put another way, there are two possible causes of your battery dying overnight... 1) The battery is toast. A properly conducted "load test" will give you the truth on if it's toast or not. Caution that not many auto parts store sales people know how to properly conduct a load test. Done incorrectly a load test can say the battery is good when in fact it's bad. I'd find a battery specialty shop and have them test it. 2) The other possibility is a device is draining your battery. Like an improperly installed relay, improperly installed burglar alarm, a big audio amplifier isn't shutting off, your alternator has a shorted rectifier (aka diode), etc.
 
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