Start Stop battery out again

dchemphill1

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9 months after having my Start Stop battery changed out....the new one is going again! Warranty on Jeep runs out end of the month but the battery has warranty...so should be good. Hard to believe the quality of the OEM battery! Really 9 months!

 

Garry in AZ

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Yeah, those batteries are junk. They tend to fail more often on Jeeps that are used for short trips or commutes. I plan on removing the one in my Jeep altogether, as I have the start stop function disabled anyway.
 

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9 months after having my Start Stop battery changed out....the new one is going again! Warranty on Jeep runs out end of the month but the battery has warranty...so should be good. Hard to believe the quality of the OEM battery! Really 9 months!
Not that you should have to, but can you/are you willing to put your Rubi on a trickle charger when the vehicle is parked at home?

Putting such a device on the terminals of the main battery charges both batteries.

As an alternative, if you're willing to run with ESS off, we can talk about how to bypass the ESS battery all together.
 
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dchemphill1

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Not that you should have to, but can you/are you willing to put your Rubi on a trickle charger when the vehicle is parked at home?

Putting such a device on the terminals of the main battery charges both batteries.
Yes I can do that...I trickle charge my tractor battery all winter.
 

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Mine lasted about 2.5 years and just went out. Planning to get them to replace it under warranty on Monday (and hopefully the primary battery too). Then I will keep the Aux battery disconnected since I keep start/stop disabled all the time anyway.
 


Fudster

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9 months after having my Start Stop battery changed out....the new one is going again! Warranty on Jeep runs out end of the month but the battery has warranty...so should be good. Hard to believe the quality of the OEM battery! Really 9 months!
It's frustrating but may boil down to what remedy best suits your needs.

If you want that battery working and have the ability to use ESS I think trickle charging may be the best thing to try first; deference to the idea that the $ your saving on gasoline pays for the trickle charger's electric.

On the other hand, if you're willing to not use ESS, taking the Aux battery out of the electrical schematic of the vehicle is an option. Links on how to do so are available on request.
 
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dchemphill1

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It's frustrating but may boil down to what remedy best suits your needs.

If you want that battery working and have the ability to use ESS I think trickle charging may be the best thing to try first; deference to the idea that the $ your saving on gasoline pays for the trickle charger's electric.

On the other hand, if you're willing to not use ESS, taking the Aux battery out of the electrical schematic of the vehicle is an option. Links on how to do so are available on request.
Would love to know what needs to be done to get the Aux out of the loop.
Thanks
 

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Reinen

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Did you replace both the Aux and Main? If not that's your problem. They're not two separate batteries for two separate things. They're linked. If one is new and the other is older, the new battery will get destroyed very quickly because it will constantly try to charge the older battery to a level it can no longer hold.
 

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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
 


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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 .
 

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Would love to know what needs to be done to get the Aux out of the loop.
Thanks
If you go this route it would be prudent to make sure that ESS cannot engage.

The reason for this is that using the now only main battery during ESS events, you are potentially robbing it of the power it needs to re-crank the engine post ESS event.

While many vehicles run ESS systems with 1 battery, as you may know/appreciate, the whole idea of two batteries in the JL was to allow appliances to run off the Aux battery during ESS events, to save the main battery for the (bulk) of the crank. In truth, both batteries, if connected, provide cranking power.

The two methods for taking the Aux battery "out of the picture" both require you to remove from the main battery's negative terminal the black cable whose distal end is connected to the Aux battery's negative terminal. As there are two factory black cables on the main battery's negative terminal, in order to determine which one to remove you should visualize the body ground nuts (there are 2) on the passenger's front quarter panel under the hood. One of these black cable's distal end is at this body ground. Don't touch that cable. It is the other cable that should be removed from the main battery's negative terminal, electrical taping its free end.

Having done this, given that you have a 2020, you can attempt to crank. Expect it to fail (because no current is seen on the Aux battery which you've taken out of commission with the cable removal.)

But, and this is important, the second attempt at cranking should then cause the vehicle to try using solely the main battery to crank. If successful the EVIC should display a "ESS off" light, and your done.

As an alternative--as some people hate seeing such idiot lights-- you can follow a similar procedure here https://www.jlwranglerforums.com/forum/threads/jumperless-aux-battery-bypass.95945/ that additional involves the removal of fuse 42 in the Power Distribution Center (PDC): that black fuse box under the hood, on top, closest to the front passenger's seat.

This method won't turn that idiot light on (and ESS off) so you should prevent ESS from engaging either by pushing the ESS off button each time you cold crank, or purchasing aftermarket tech that will disable ESS for you automatically such as Smart Stop Start of the Z Automative JL Tazer.
 

Fudster

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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 .
This situation highlights the fact that turning off ESS, or an ESS system that won't engage is entirely separate from electrically taking the Aux battery out of your JL's electrical circuitry.

If both batteries are hooked up, they are connected in parallel at all times but during ESS events and an instant at cold crank. Such parallel connections can have a defective battery rob the good of power.
 
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dchemphill1

dchemphill1

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Did you replace both the Aux and Main? If not that's your problem. They're not two separate batteries for two separate things. They're linked. If one is new and the other is older, the new battery will get destroyed very quickly because it will constantly try to charge the older battery to a level it can no longer hold.
The main battery was load tested and good in January...
 

Reinen

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The main battery was load tested and good in January...
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.

 

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