Start Stop battery out again

Dyolfknip74

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Here's the thing. Batteries aren't like a light switch that flip from "good" to "bad". They progressively lose their ability to maintain a voltage level. "Tested Good" means that it hasn't deteriorated below an arbitrary point where it's considered no longer useful. But it can be rather close to it and still be "tested good". It's guaranteed to be worse than your new battery.

That old battery will act like a vampire and suck the life out of the new battery until they are both equally bad. So if you replace one, always replace the other (in spite of it still being "good") so both batteries are always at equal levels of wear. That will maximize the lifespan of both batteries.

If you replace batteries individually, you will constantly be in a situation where one battery is stressing the other. You will go through a lot of batteries this way.
Well, to be fair, lithium batteries will go from good to bad like a light switch but that has no bearing on this conversation. ;)

 

grimmjeeper

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What brand do you recommend. I think I am going to replace both.
A lot of brands are just different labels on batteries manufactured by just a few companies. Pretty much all of the aftermarket AGM batteries are good. Certainly better than the junk you get from the dealership.

I went with Die Hard because they were convenient to buy at a local parts store.
 

grimmjeeper

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Those that have had the Aux Batt fail…. What are the symptoms? How do you know it’s failing? I’m just curious to know what to look for if it should start to happen to me. Thx!!
I started getting messages about aux switches not being available.
 

TheNewGuy

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Those that have had the Aux Batt fail…. What are the symptoms? How do you know it’s failing? I’m just curious to know what to look for if it should start to happen to me. Thx!!
Constant "Start stop not available battery charging" message
 

slowpoke387

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Mine is a 3.6 engine, 2018, both batteries amazingly enough are still good even after completely discharging them by accident like 6 times already.. I recently removed fuse 42 and disconnected the negative terminal for the ESS battery... my JL starts normal and I have no warning lights.. I have a Tazer to disable that pesky ESS... removing fuse 42 / disconnecting the ESS battery is the simplest solution
3.6's dont seem to be having this issue. 2.0 is the culprit I believe.
 


guarnibl

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My aux battery went off like half a year ago. With that, so did my auto start/stop. Never a problem until this past Sunday. My car wouldn’t start, just took it in to my dealer today and since I bough it pre-owned , sadly the battery wasn’t under warranty. Now I have to pay $1300 to get both batteries replaced, plus the battery sensor. Sucks .
$1300? What?

Delete the aux battery and just get a stout main battery and save $1000...
 

Capital CDJR
 
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