TJ wont start unless jumped?

[Chipz]

Hi, i was hoping some one might be able to help me diagnose my problem. I have a 01 Tj wrangler and she doesnt want to start, battrey is very new and i can have it on charge all night and still not be able to start the following day with a full charge. Acts as if its flat such as very slow cranking or just clicking. But when i jump the battrey it starts fine. Car charges fine once driving as it should but once i turn car off i have to jump it again. 3 new batterys ive had thinking that was problem but its not.
Any help would be appreciated cheers.

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[JeepNWilly]

I have had issues with starter giving me a slow crank as if my battery was dead but in my case a Jump start did not help. I would still get the started tested maybe.

 

[Chris]

Hmm, if it's not the battery, that sounds like it could be the starter to me.

 

[Jerry Bransford]

More than likely nothing more than a bad/corroded/loose/dirty battery connection. Even when they look fine to the eye, battery connections can be so bad inside where you can't see that they can act like the battery is dead. Use a battery brush like below to thoroughly wire brush the battery posts and inside of the battery connections and see if that helps. If not check where the cables are crimped to the battery connections and at the ground point.

This battery brush kit sells for $4 or so at your local auto parts store. And since the engine starts when you connect the jump start cables to the battery connectors, my bet is on nothing more than the above mentioned bad battery connections at the battery posts. Or your "fully charged battery" is actually bad which can only be confirmed by having someone who knows that they're doing perform a "load test" on the battery. Only a properly conducted load test can accurately indicate a battery's true health.

 

[Chris]

Duh... How did I forgot about the battery terminals. That's the first place I would check.

 

[Chipz]

Thanks for the tips, ill clean up the connections when i get home and see if that helps. Cheers

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[Chipz]

Cleaned connections with no change. Im getting 12.6v at starter motor.

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[Chris]

Are the connectors tightened down really snug?

 

[Chipz]

Yeah mate and when i turn key to accessories it drops to 10v

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