Battery/Alternator Issues -
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Unread 11-21-2013, 06:59 AM   #1
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1981 CJ7 
Join Date: Sep 2013
Location: Charlotte, NC
Posts: 18
Battery/Alternator Issues

Hi All,

A few weeks ago, I replaced my battery and alternator ('81 CJ7 with a '76 304 AMC). I had to go back in and tighten the belt and negative connector on the alternator because it wasn't producing enough voltage to keep the battery charged. That seemed to fix the problem (the problem being a consistently dead battery). Yesterday, I saw a voltage drop on the battery and sure enough, it gave out on me again. Thinking it was a connection/tension issue that arose because of the temperature change here in Charlotte, NC, I tightened the belt again and assured the connections were solid. My volt meter is showing the alternator producing roughly 19 volts, but the battery continues to trickle down from 12 after jumped.

My question is this... What the heck could be the problem? Why would it have charged the battery fine for a few weeks, then suddenly crapped out? I feel like it is a connection issue, but I'm not sure where else to troubleshoot. Help!!

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Unread 11-21-2013, 07:47 AM   #2
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1977 CJ7 
Join Date: Mar 2011
Location: , Northern Arizona
Posts: 2,903
I'm not so sure the alternator isn't doing its job. What you're describing sounds more like some sort of a parasitic drain.

What you might want to do if you have a VOM is open up each circuit one at a time and look for amperage. I'd almost bet there's one circuit that has a ground on it.
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Unread 11-21-2013, 09:30 AM   #3
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1985 CJ7 
Join Date: Jul 2010
Location: The Mojave Desert Palmdale Ca. U.S.A.
Posts: 4,808
Charge the battery and leave it disconnected over night.
Have a real load test done for amps/volts.
Think'n you battery has issues.
X2 on patristic drain in your system.
Lets eliminate the battery as a fault.
Then go have your alt. tested.
Check ALL engine/frame/body gnds.
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Unread 11-23-2013, 11:08 PM   #4
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1981 CJ7 
Join Date: Sep 2013
Location: Charlotte, NC
Posts: 18
I spent the better part of today messing around with the circuit. I tested numerous potentials for drain and it turned out that the voltage regulator was the problem. Thanks to you all for your great insight!!!
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Unread 11-24-2013, 11:06 AM   #5
Running On Empty...
1973 CJ5 
Join Date: Aug 2007
Location: South West Indiana
Posts: 10,149
19 volts is a dead giveaway the voltage regulator is shot!
You should NEVER see more than 14.5 volts at any given time for any reason.

China voltage regulators do that sometimes... They work OK for a little bit, then go nuts.

19 volts WILL damage the battery, have it tested! Get warranty if you can just to make sure you didn't cook/warp plates that will screw you later.
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