Help with final (WORKING/SAFE) AUX battery bypass method...?

[Nash_Dj]

Hello Jeep Enthusiasts (and Experts),
I just traded my 2021 eTorque JLU Willys for a 2025 Rubicon (as of yesterday), which now includes the infamous AUX battery.
Over the years, I've read countless posts about AUX battery issues and bypass methods. Since my old Jeep didn’t have one, I never had to worry, until now. So I’m hoping someone can give me a clear answer, please:
What’s the current best way to properly bypass the AUX battery?
I’m fairly technical, so no need for a deep dive - just a quick, one sentence correct step-by-step instruction, or a link to the definitive guide would be perfect.
Not being lazy, just overwhelmed by the sea of conflicting info out there and required time to sift it all. I’ve got dozens of mods and accessories from my old Jeep waiting to go on the new one, and I’d love to check this off my list first and quickly
Thanks so much in advance!

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[Nash_Dj]

And yes, the dealer agreed on transferring my old roof (with the Rhino Rack backbone and the tray, along with my 270 awning and Rotopax mounts) from my old Jeep to the new one...

 

[shane h.]

Here's what I did over three years ago now...

Completely removed the Aux battery
Wired the Aux battery hot up to the main battery positive (H7 AGM in mine)
Removed the Aux battery negative from the main battery and taped it off

I didn't mess with any fuses. I do run a Tazer to keep ESS off, but I had that before the delete. I've never had any issues with this setup.

 

[Aonarch]

I just disconnected the aux battery, removed it from the vehicle, taped the cables, and then removed fuse 42.

No issues.

I didn't remove any of the cables, because my battery cables are nearly wrapped in a loom, and I didn't want to hack it up.

I also installed a H7 battery and didn't have to modify my battery tray.

 

[X35]

Am I correct that the negative cable from the aux battery is the only circled in red on the photo below?

 

[shane h.]

Am I correct that the negative cable from the aux battery is the only circled in red on the photo below?

I undid that one then used a tester to test continuity from the end at the Aux battery to make sure it was the right one. It was the right cable to disconnect for a 2019. Better safe than sorry.

 

[mbrose1994]

For your consideration, I electrically eliminated my AUX Batt.
My #N3 fuse is now disconnected, nothing can blow it.

See thread: Auxiliary Battery Elimination, post #14 (final post).
The prior posts all contribute excellent information regarding my end result.
Hope this helps.

 

[Nash_Dj]

Here's what I did over three years ago now...

Completely removed the Aux battery
Wired the Aux battery hot up to the main battery positive (H7 AGM in mine)
Removed the Aux battery negative from the main battery and taped it off

I didn't mess with any fuses. I do run a Tazer to keep ESS off, but I had that before the delete. I've never had any issues with this setup.

Thank you. If you removed the AUX battery completely, would that make the negative cable (for AUX battery) "free" on both ends, and if so, can the cable be removed completely as well?

 

[shane h.]

Thank you. If you removed the AUX battery completely, would that make the negative cable (for AUX battery) "free" on both ends, and if so, can the cable be removed completely as well?

Yes.

 

[Nash_Dj]

Am I correct that the negative cable from the aux battery is the only circled in red on the photo below?

From a ton of posts I read, it appears that the position of that cable could be on the either side, so my understanding is that it should always be the thinner of the two cables (the thicker is the main battery ground)...

 

[mbrose1994]

Thank you. If you removed the AUX battery completely, would that make the negative cable (for AUX battery) "free" on both ends, and if so, can the cable be removed completely as well?

Yes, has no purpose if AUX batt removed. Same for the 2 positive (POS) AUX batt cables.
However, I suspect the effort will be aggravating.
And some risk from the forces required to remove the cables from their channels.

I am unwilling to do that. If you do, successfully, Kudos Man!

 

[Mguy]

@mbrose1994,

Nash_Dj said:​

If you removed the AUX battery completely, would that make the negative cable (for AUX battery) "free" on both ends, and if so, can the cable be removed completely as well?

Yes, has no purpose if AUX batt removed. Same for the 2 positive (POS) AUX batt cables.​

Blue text above is incorrect. The "two" cables that are clamped to the aux battery positive stud are stock for alternator equipped JLs and, acting as a "single" connection through the PCR and N3 fuse, provide power to N1 loads. They substitute for the fuseless N1 to N2 strap that is stock for non-alternator models. The "two" cables can only be removed if a power-sourced connection is added to N1. See post 617 in this thread.

 

[Nash_Dj]

@mbrose1994,

Nash_Dj said:​

​

Yes, has no purpose if AUX batt removed. Same for the 2 positive (POS) AUX batt cables.​

Blue text above is incorrect. The "two" cables that are clamped to the aux battery positive stud are stock for alternator equipped JLs and, acting as a "single" connection through the PCR and N3 fuse, provide power to N1 loads. They substitute for the fuseless N1 to N2 strap that is stock for non-alternator models. The "two" cables can only be removed if a power-sourced connection is added to N1. See post 617 in this thread.

Thank you for this clarification and the link to the thread....

 

[Cuyose]

For your consideration, I electrically eliminated my AUX Batt.
My #N3 fuse is now disconnected, nothing can blow it.

See thread: Auxiliary Battery Elimination, post #14 (final post).
The prior posts all contribute excellent information regarding my end result.
Hope this helps.

I read this , but don't understand how you taped off both POS of the AUX without getting to the aux battery.

 

[mbrose1994]

I read this , but don't understand how you taped off both POS of the AUX without getting to the aux battery.

Technically, I disconnected the 2 POS leads coming up from the AUX to the high voltage bar. If memory serves, AUX POS leads when to posts #1 and #3. Those loose ends I taped up. Then added the jumper from post #2 to post #1. Which leaves post #3 empty.

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