Main battery needs replacing, how do I tell about the aux?

[j.o.y.ride]

Main battery definitely needs to be replaced, do I just need to have the aux load tested? I don't use start/stop so unless that's just a bad battery I dont see why it would be dead.

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[jeepers29]

From everything I have read here, the aux goes bad then drains the main. I do believe the train of thought is to replace them at the same time or to replace the main and delete the aux. I will be doing the latter.

 

[j.o.y.ride]

I do have the hardware for the aux bypass I had just left it connected this whole time. I can stop that main battery and then bypass the aux for now and deal with it later

 

[JRobes]

I do have the hardware for the aux bypass I had just left it connected this whole time. I can stop that main battery and then bypass the aux for now and deal with it later

That would be my route. If I had issues down the line after the aux delete then replace both.

 

[j.o.y.ride]

That would be my route. If I had issues down the line after the aux delete then replace both.

I need a refresher on the bypass setup.

IIRC I have the jumper on posts 1 & 2 to retain the + side of the AUX battery to keep electronics connected.

I then have a 40A fuse on this for security.

I also have a heavy duty switch on the negative from the aux to the main battery which, when 'on' will power the aux side and when 'off' will leave the aux out of the system as a battery... but the jumper keeps the lights on so to speak of items that are running through it.

 

[ShadowsPapa]

From everything I have read here, the aux goes bad then drains the main.

You need to stop reading that BS. As many have had a main go bad as the other way around but because a couple on the web have said the aux goes first and kills the main battery, that's become the de facto way it goes. That's wrong and perpetuating the myth isn't doing anyone any good.


All one needs to do Is pull fuse F42, take the aux battery ground off the IBS, insulate it, tie it back, whatever, and you're done.
No jumper is needed, no "equipment" is needed unless you want to harvest the PCR and aux battery wiring from where it resides. IF you leave it all in place, you need zip, zero, nothing else at all.
Pulling fuse F42 prevents the PCR from opening for the battery check, pulling the aux negative cables prevents it from having anything to do with anything.

Not using ESS has nothing to do with the aux battery going bad or dead. It's like any other small battery in a place that's hot - they go bad. 3 years is about max life out of Jeep batteries.
There's a myth that if you don't use ESS, the aux battery won't go bad, or that it prevents trouble - it's not correct.

 

[SelfmodJT]

Just out of curiosity, what voltage should the battery screen show when the aux battery is fully charged and ready for the ess to start engaging? Is there a parameter that it will fall in?

 

[sharpsicle]

Just out of curiosity, what voltage should the battery screen show when the aux battery is fully charged and ready for the ess to start engaging? Is there a parameter that it will fall in?

Battery screen shows the system voltage, not the individual battery voltage. And both batteries need to be in good shape for the ESS system to function.

 

[j.o.y.ride]

All one needs to do Is pull fuse F42, take the aux battery ground off the IBS, insulate it, tie it back, whatever, and you're done.
No jumper is needed, no "equipment" is needed unless you want to harvest the PCR and aux battery wiring from where it resides. IF you leave it all in place, you need zip, zero, nothing else at all.
Pulling fuse F42 prevents the PCR from opening for the battery check, pulling the aux negative cables prevents it from having anything to do with anything.

Depends on what you're trying to accomplish. The setup I have is meant to be able to use the aux battery as a self jump start. You can selectively include or exclude the aux battery. I had forgotten about and/or been lazy to make sure the aux was charged. Every month or so bring it back into the system on a drive to be sure it's charged and then bypass it by disconnecting the ground via a switch. Leaves it out of the system but kept on board as a spare in case it's needed. May as well keep it around for an emergency vs a hard bypass... so long as you keep it charged up which I did not.

 

[Mister Lamb]

I'd just spend the extra $100 and replace both to save the headache

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