Jumperless Aux Battery Bypass

[Jebiruph]

So many threads on ESS, jumpers, bypass, dual batteries, aux battery, etc. and so much good info thanks to @Jebiruph and many others.

Simple question ? what’s the best option for those of us running the factory 2-battery setup to ensure reliability especially when offroading (overlanding)?

I hoped the synopsis thread would be the answer, but that threads going on for many pages and now with this new fuse removal option, I’m just confused as ever. Thanks for your help.

Pull fuse 42, disconnect the aux battery ground and keep the aux battery charged as an emergency backup in case the main battery dies.

Sponsored

 

[WhatExit?]

Pull fuse 42, disconnect the aux battery ground and keep the aux battery charged as an emergency backup in case the main battery dies.

Can't thank you enough for your response and all the many posts of value!

1. Pull Fuse 42 - I can do that
2. Where do I find now to disconnect the aux battery ground?
3. And how do I keep the Aux battery charged (run leads to it that go to a disconnectable trickle charger)?

 

[Red Willy]

Maybe I'm missing something here, but I just went out to my '21 manual trans 2 door and pulled the correct fuse (F42) and removed the aux battery neg terminal (13mm nut). I have no lights on the dash or power at all. I replaced the fuse and terminal and all is back to normal.

 

[Stuckinthesand]

Maybe I'm missing something here, but I just went out to my '21 manual trans 2 door and pulled the correct fuse (F42) and removed the aux battery neg terminal (13mm nut). I have no lights on the dash or power at all. I replaced the fuse and terminal and all is back to normal.

Make sure you are pulling the right negative cable. In MY21 they switched which cable goes to the aux. Check out this thread by @Jebiruph

https://www.jlwranglerforums.com/forum/threads/ess-battery-cable-change.86624/

 

[Red Willy]

Make sure you are pulling the right negative cable. In MY21 they switched which cable goes to the aux. Check out this thread by @Jebiruph

https://www.jlwranglerforums.com/forum/threads/ess-battery-cable-change.86624/

Figures.... I should have checked it with an ohm meter. Thanks man!

 

[Red Willy]

Yup, that did it! So grateful to this forum, the people and the information here!

Also a big thanks to @Jebiruph for all his diagnostic workaround for this crap they make us live with in Jeep life.

 

[tbaker]

I did this today and my gladiator started right up the only thing is on my dash it’s saying auxiliary switches not available until battery is charged any ideas I had started getting this message a few weeks ago I haven’t driven my gladiator in a few days I am hoping that’s what’s wrong I took the correct fuse out number 42 and disconnected the correct negative battery cable

 

[Stuckinthesand]

I did this today and my gladiator started right up the only thing is on my dash it’s saying auxiliary switches not available until battery is charged any ideas I had started getting this message a few weeks ago I haven’t driven my gladiator in a few days I am hoping that’s what’s wrong I took the correct fuse out number 42 and disconnected the correct negative battery cable

I would check the state of the main battery. When the aux starts going bad it usually also affects the main as well. You may need to buy a new main battery.

 

[zyt]

I did this today and my gladiator started right up the only thing is on my dash it’s saying auxiliary switches not available until battery is charged any ideas I had started getting this message a few weeks ago I haven’t driven my gladiator in a few days I am hoping that’s what’s wrong I took the correct fuse out number 42 and disconnected the correct negative battery cable

I am also experiencing this as the weather gets colder. I took delivery almost 5 years ago in Jan 2018. We will see how long the main battery lasts.

 

[tbaker]

The battery voltage on the dash is reading 14.5 if you can trust that I have a 2020 rubicon gladiator

 

[Stuckinthesand]

The battery voltage on the dash is reading 14.5 if you can trust that I have a 2020 rubicon gladiator

If it reads a steady 13.8 or above even while driving this is a sign your main is bad. That is telling you the intelligence battery sensor is constantly calling for charging the battery. You should see it drop to around 12.5v while driving.

 

[AndyMcConnell]

If it reads a steady 13.8 or above even while driving this is a sign your main is bad. That is telling you the intelligence battery sensor is constantly calling for charging the battery. You should see it drop to around 12.5v while driving.

Only valid way to see the battery condition would be when not being charged or drawn from... After driving a while and the battery has an opportunity to get fully charged (maybe for the first time in a long while if the aux was drawing off it all the time when it was bad) then you should see the charge level even out without the alternator charge voltage level - though 12.5 seems low for a nominal 12.8 volt battery.

While the alternator is charging the battery, you really cannot see the state of the battery itself (I know the smart alternator can stop charging at times), so drive a while and shut down and then check where it sits. My 2020 JL on the original battery sits around 12.6 or 12.7 after the vehicle has been off for a couple of hours. Shortly after shutdown after a normal drive, it is normally 12.8 or 12.9

 

[azwjowner]

Only valid way to see the battery condition would be when not being charged or drawn from... After driving a while and the battery has an opportunity to get fully charged (maybe for the first time in a long while if the aux was drawing off it all the time when it was bad) then you should see the charge level even out without the alternator charge voltage level - though 12.5 seems low for a nominal 12.8 volt battery.

While the alternator is charging the battery, you really cannot see the state of the battery itself (I know the smart alternator can stop charging at times), so drive a while and shut down and then check where it sits. My 2020 JL on the original battery sits around 12.6 or 12.7 after the vehicle has been off for a couple of hours. Shortly after shutdown after a normal drive, it is normally 12.8 or 12.9

My nearly new Jeep never drops below 14.1 even if I fully charge the batteries on a tender before starting and then drive it for hours.

 

[Rhinebeck01]

My sport is brand new. six months old.
voltage reads 14.4 almost all the time. Always has.
if I let ess stop the engine you see the voltage start dropping.
otherwise, 14.4 while engine is running.

14.4 "almost all the time" is not at all typical.. it is not what you want to see or should see.

As for the earlier post that says "drop to around 12.5v while driving"., well that is not at all typical either.

 

[Stuckinthesand]

14.4 "almost all the time" is not at all typical.. it is not what you want to see or should see.

As for the earlier post that says "drop to around 12.5v while driving"., well that is not at all typical either.

Yeah I didn’t proofread. I thought I had 12.7v an up. Apologies for the confusion everyone.

Sponsored