Replacing Main/Aux batteries

[chisel66]

I need to replace both main/aux batteries and am NOT particularly mechanically inclined. I found a detailed You Tube video that shows how to do it step-by-step. I am prepared to do it, just wondering how difficult the aux battery really is to get to? It is pretty buried, and I don't want to create more problems than just two dead batteries. Is there anything I should be prepared for?

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[DaltonGang]

Leave the Aux Battery in place, and replace the main battery. Then do the Aux Battery Bypass. There are.several threads dedicated.to this topic. Here is one I have started, a while back.

https://www.jlwranglerforums.com/fo...sing-the-aux-battery-easiest-solution.100296/

 

[Ratbert]

First verify that you actually have an aux battery. Some do, some don't. Some are simple to get to (EcoDiesel) and the rest are a pain in the ass.

 

[Terrymo]

As @Ratbert said first confirm that you do not have a 48 volt etorque secondary battery under the vehicle rather than the small secondary 12 volt auxillary batttery in the passenger fender area. Perhaps you already know what you have, but people have done the work to get to the 12 volt auxillary battery holder only to discover it’s empty because they have the etorque battery, Take a quick look under the vehicle. Here’s a couple of pics of what you’re looking for.

 

[SBLACK502]

If you are dead set on replacing both and not bypassing, I would suggest getting to the aux through the fender. To me it’s way easier and less risk of issues than removing the fuse box.

 

[Nokones]

In regards to the 48 Volt Aux ESS Battery, that is supposed to be a 7 year battery. It is a Lithium battery. I'm not sure what is the factory warranty for this battery. It may be just covered on the bumper-to-bumper warranty.

 

[Ratbert]

If you are dead set on replacing both and not bypassing, I would suggest getting to the aux through the fender. To me it’s way easier and less risk of issues than removing the fuse box.

Unless you have an EcoDiesel. It's simply under a panel under the main.

You'd think they'd retrofit that improvement into other engines since they have a couple more years of JL, but I guess not.

 

[Terrymo]

In regards to the 48 Volt Aux ESS Battery, that is supposed to be a 7 year battery. It is a Lithium battery. I'm not sure what is the factory warranty for this battery. It may be just covered on the bumper-to-bumper warranty.

Yes good info…I should have said the 48 volt etorque battery is a factory warrantied battery that should be serviced by a factory authorized tech.

 

[AndySpill]

I need to replace both main/aux batteries and am NOT particularly mechanically inclined. I found a detailed You Tube video that shows how to do it step-by-step. I am prepared to do it, just wondering how difficult the aux battery really is to get to? It is pretty buried, and I don't want to create more problems than just two dead batteries. Is there anything I should be prepared for?

Please make sure that your model of JL has two batteries. If you pop the cover of the Power Distribution Center (PDC): that black box on the passenger's side, i.e. your intelligent fuse box, on the side of the PDC closest to the driver's side there will be a row of high amp fuses of which the one closest to the front of the vehicle we'll call N1. If there is a factory metal jumper between N1 and its adjacent terminal, N2, you probably don't have an Aux battery.

That said I don't know if the video you found finds you accessing the Aux battery from the side or above.

Most people prefer to get to the battery from the side, but if you do, I recommend that you first acquire replacement plastic rivets and means to install them as such side access can involve the existing platic rivets getting broken in order to access the battery.

https://www.jlwranglerforums.com/forum/threads/plastic-rivets-and-tool.22297/

If you search this on youtube "HOW TO Replace the Main and Auxiliary Battery on a Jeep JL Wrangler and Gladiator Truck w/o eTorque" you will be brought to a video that shows how to access the Aux battery from above.

This method clearly has the potential, if you are careless, of causing damage to the electronic connector pins of the Power Distribution Center, and as a result I think it is why Stellantis has dealer techs come in thru the side to get to this battery, yet it is my preferred method because it is just visceral for me to break pins, plastic and inexpensive through they are, to effect this swap.

This video will give you a good listing of all the tools you need, one in particular being a female torque bit kit (e.g. https://www.amazon.com/LEXIVON-Socket-Chrome-Vanadium-13-Piece/dp/B087V5QYT9/ref=sr_1_1_sspa?crid=1PATB40HS83MP&dib=eyJ2IjoiMSJ9.ezlbWY3_2J9aiLZlZPWXPbnqk_1HBo3I6x-UNQ4WYGEJaaezEm2NLm4i7DiOsyJWiBEHEKSN4DrUZwwp5lyVU7BCaevgTtLImpiDqXx_5b7uxkAsNu0q-nqZezKWQZI57yU4H4aAT3F4Sflust_85BqNUFXEZ6efwFR_OaV7Eba2F5AMhb2LHwmGXQCG-0v5AMyEDEBEsFHUl2KykrPfMPxnsvfebcHFI5FWsZ14uX6bvGRbgmo4GnVhoEEtqeXCLHjr4duBcE33oHDS-08mc0wiIBFPZ5-d7ke5bOBqT08.NdidZ6Wz254DeoGquMVT6PZaK-T45bjC1QAHuYjm7Ug&dib_tag=se&keywords=reverse+torque+socket+set&qid=1737217663&sprefix=reverse+torqu,aps,113&sr=8-1-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9hdGY&th=1) to remove the battery terminal studs from the old Aux battery and repurpose them on the new, as this group size battery seems to get sold without these studs. If memory serves me correctly its the E6 bit that you'll need to do this.

https://www.jlwranglerforums.com/fo...ent-the-easy-way-pull-the-fender-flare.56807/

 

[MauiSteve]

I recently did mine, not a difficult job, just a bit of patience to carefully seat connectors. Much is made of this job but did not find it to be very involved. If you suspect batteries, do both, doing only one, if the other is bad, brings down the new one. These batteries are in parallel making them one "battery", they will drag each other down. I got mine at O'Rileys.

 

[AndySpill]

Oh, and when replacing the main battery, regardless of whether your JL came equipped with an H6 or H7 group battery I would advise, often for the same $, that you get the larger H7 battery.

Either will fit, although you will likely have to remove a (removable) cleat in the main battery tray to fit an H7 if you originally had an H6.

 

[Old Dogger]

I just eliminated the aux Battery, and installed a O'reily's AGM Super Start H7 Battery, in our 2018 JLR. IMO..this was the best and easiest to do!!!!!!!!! It works just great!

 

[Heimkehr]

Oh, and when replacing the main battery, regardless of whether your JL came equipped with an H6 or H7 group battery I would advise, often for the same $, that you get the larger H7 battery.

Either will fit, although you will likely have to remove a (removable) cleat in the main battery tray to fit an H7 if you originally had an H6.

Exactly what I did after removing the original H6.

Removing the battery tray's H6 spacer, to make room for the mildly larger H7, was dead simple. The nominally faster engine starts are reassuring, too.

I also isolated the OEM ESS battery (disconnect & tie off related Neg batt cable; remove Fuse F42) after the new Interstate AGM H7 was installed. Done and done.

 

[nositting]

as others have said, go through the fender, it’s easier. be proactive and get extra fender clips before you start

 

[chisel66]

I recently did mine, not a difficult job, just a bit of patience to carefully seat connectors. Much is made of this job but did not find it to be very involved. If you suspect batteries, do both, doing only one, if the other is bad, brings down the new one. These batteries are in parallel making them one "battery", they will drag each other down. I got mine at O'Rileys.

Thanks all for the responses - I ended up doing it and went in from above, getting the PDC out was a little challenge but not too bad. Once I got the aux battery it was easy enough to replace and get reassembled. Fired right up - only issue is check engine light still on. I've read a couple of fixes and will try those, otherwise runs great.

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