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Discussion Starter #1
Its driving me NUTS......
OK, replaced original battery about a month ago ( optima red top)
Jeep sits for 2 days and battery voltage goes from 12.61 to 12.39
I put a digital meter measuring amp draw on the battery and I get .88 ma
I have pulled EVERY fuse out one at a time , behind the glove box, and also under the hood.
The reading never changes from .88 ma
What am I missing?????
 

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I'd have to look but I think mine has a slight draw also .8ma isnt much though unless somebody else chimes in before I get home I'll look in the FSM and post up

Eric
 

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I wouldn't worry about 880 micro amps killing your battery anytime soon unless the battery is bad...

:wink:

However, if you actually mean 880 milli amps, then the battery could be in trouble. Try disconnecting the (+) cable to the starter and/or the alternator, there may be an issue in the rectifiers or solenoid. Disconnect the ground from the battery first so you don't inadvertantly short anything out.

ken
 

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Discussion Starter #7
i'm assuming its milliamps that my digital gauge is reading set at ma

would it be normal for the battery to go from 12.61 to 12.39 in just 2 days ??

I will try the alternator test .
 

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dynamike said:
i'm assuming its milliamps that my digital gauge is reading set at ma

would it be normal for the battery to go from 12.61 to 12.39 in just 2 days ??

I will try the alternator test .
Try the starter too...
 

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Am I missing it? 12.39 isn't really a problem, and it should still start perfectly fine. Try disconnecting the battery and letting it sit for 2 days, you might still find it reading 12.3-12.4V after a few days with NOTHING on it.

Does this thing not start or something?
 

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Discussion Starter #10
DoctorD said:
Am I missing it? 12.39 isn't really a problem, and it should still start perfectly fine. Try disconnecting the battery and letting it sit for 2 days, you might still find it reading 12.3-12.4V after a few days with NOTHING on it.

Does this thing not start or something?

Doc.......thanks for chiming in.....
after it sits a couple days (not a daily driver).........and the battery gets down to the 12.3 range.......NO it wont start !
WHat is the normal battery voltage range for starting a Jeep ??

The other strange thing (oh now you tell us).......is if i put my battery tender (not charger) on it...after a short time period. it reads like 14.45 dc volts.......isnt that a little high ? I thought charging was around 13.9 volts.

I will try and test the starter and alternator once I get some more info.....any tricks to testing those ?

Thanks for your help guys!!!!
 

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How old is the battery? It is the season of dead and dying batteries :)
 

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dynamike said:
DoctorD said:
Am I missing it? 12.39 isn't really a problem, and it should still start perfectly fine. Try disconnecting the battery and letting it sit for 2 days, you might still find it reading 12.3-12.4V after a few days with NOTHING on it.

Does this thing not start or something?

Doc.......thanks for chiming in.....
after it sits a couple days (not a daily driver).........and the battery gets down to the 12.3 range.......NO it wont start !
WHat is the normal battery voltage range for starting a Jeep ??
A battery that still has capacity can start the engine at even 11 volts.

dynamike said:
The other strange thing (oh now you tell us).......is if i put my battery tender (not charger) on it...after a short time period. it reads like 14.45 dc volts.......isnt that a little high ? I thought charging was around 13.9 volts.

Hard to say. Some cheap chargers will go to as high as 17V or more. If yours seems to be going higher than USUAL, the battery may be sulfated, which is what it seems like you are dealing with.

dynamike said:
I will try and test the starter and alternator once I get some more info.....any tricks to testing those ?

Thanks for your help guys!!!!
Yeah, but testing the battery needs a carbon pile. I doubt you have one. Load to 1/2 the 0 degree CCA for 15 seconds, record the result at the end of the test. It should be above about 9.3.

What you CAN do is pull the ASD relay (so it won't start), and crank the engine for 10 seconds while monitoring the battery voltage during the event. If you get down to 10 or so, your battery is most likely crap....assuming the engine and starter is mechanically OK otherwise.

To test the alternator, reinstall the ASD relay, start the engine and run for a minute or two with all the accessories on (HVAC on HIGH, all lights on EXCEPT the hazards, etc. and rev the engine to 2000 RPM, and monitor battery voltage. You should be at or near 14V.
 

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Wow, its amazing the places people go when talking about batteries. A fully charged battery at 70 degrees that has not been charged in a few hours should be at 12.6v ("static" battery voltage) or slightly over.

There are two things to consider. You lose almost 0.1 volts of static voltage for every drop of 10 degrees F.

So in your case, obviously you stated the battery was not on charge for some time. But what was the temp? If you are in AZ and its 50 degrees in the morning when you do your tests than 12.4v is ok. In addition (as you seem to know) battery state of charge has an impact on static battery voltage. The problem is that a battery at 12.0v is discharged more than 50% at 70 F.

This is why a quick analysis of battery voltage can be so misleading. A frigid night in MI can leave me with a battery in the 11.8 volt range, but my Jeep will start up fine. But if a warm summer (80 F) night here in MI left me with a battery at 12.2v I would be going nowhere.

I would properly charge your Optima on a slow charger rated for spiral wound and glass mat batteries. Then I would let it sit alone and see if it goes dead.

Your propblem is almost exactly like (but faster) than my last two red top Optimas. In my case it was a bad battery both times, and it is the reason I no longer use Optima batteries. Please, no need to interrupt the OPs help thread with Optima battery flag waving. I'll admit now that my experiences may have been isolated experiences.

http://www.ccis.com/home/mnemeth/12volt/12volt.htm

This link had good info under the heading "care of your batteries". While I do not agree with all the data on the page, it is close enough. It also closely matches the information in my Advanced Auomotive Electrical Systems text.
 
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