Aux battery replacement help!

[AndySpill]

A couple questions:
-It has the MOPAR battery installed and the Aux I know that for sure. Is there a third battery you are speaking about?

No. Only 2.

-I am not sure if I want to bypass right now, so I want to try to keep the aux for now. Hopefully saving gas on short trips. You recommended going from above rather than the fender option?

I believe that coming in from the side is the path least likely to statistically cause great expense should you break something. I say "statistically " as result of the likelihood of someone breaking something expense, although unlikely, multiplied by its expense to repair/replace.

To point, to access the Aux battery from above you need to dis- and reassemble the Power Distribution Center (PDC): your intelligent fuse box that sits above. If you bend or break something, much that I think it is very plug and play, with connectors with unique shapes that prevent reassembly in the wrong place, coming in from the side your potential for loss: broken fender clips, in need of replacement, is much less and controlled. A new PDC I'll bet is North of several hundred dollars.

I urge you to follow videos on this first and equip yourself with the right tools and knowledge beforehand, including replacement clips, the right sizes of ratchets, and a reverse torque kit to reuse the existing Aux battery's post (e.g. https://www.amazon.com/dp/B087V5QYT9?ref_=ppx_hzsearch_conn_dt_b_fed_asin_title_1&th=1)

Guidance on Youtube regarding replacing the battery from above can be found be searching for a video entitled "HOW TO Replace the Main and Auxiliary Battery on a Jeep JL Wrangler and Gladiator Truck w/o eTorque"

Guidance on Youtube to come in from the side can be found here:

-Also, just confirming after removing and taping both cables from the negative terminal, I can leave the positive alone on the main?

To replace the Aux battery you will be temporarily removing one, not two cables off the negative post of the main battery. To reiterate, two cables are on that post from the factory. One has as its other end the body ground on the passenger's side under the hood. Please visualize that cable. That cable remains connected. It is the other factory cable that should be removed and have its end taped up before proceeding. This cable that I am having you temporarily remove has at its distal end the negative post of the Aux battery. Effecting this temporary cable removal breaks any circuit between the vehicle and the Aux battery.

Once the new Aux battery has been installed then un-tape and reattach this cable I had you temporarily remove.

P.S. If you want to remove both cables from the negative post of the main battery that's okay, provided you're fine with depriving the vehicle of electric and not up for an inspection in a State that is going to access your vehicle diagnostics through the ODB II Port.

Depriving the vehicle of power will cause such inspections to fail until the vehicle is driven a few hundred miles to reset things.

Removing one cable temporarily as described allows the main battery to still supply power to the vehicle while the Aux is temporarily isolated and replaced.

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[Terrymo]

If I am looking to replace my aux battery, do I only need to disconnect the negative from the main before I pull the aux? Or do I need to take off both positive and negative from the main first?

@Rhinebeck01 and @Jebiruph created several sticky threads at thd top of the Battery Talk forum. All the answers are there depending on your level of interest.

 

[munkeymike]

Thank you! I think I want to try to keep the AUX attached to try to save what I can on gas mileage if I am mainly making shorter trips in the jeep. At least that is my hope with the SS.

I haven't done the math, but it might be cheaper in the long run to not keep buying aux batteries vs the amount of gas you save.

 

[moabman-OG]

It sounds like I should work on this myself. My ESS hasn't worked in 8 months or so, I assumed the Aux was just toast and I don't use ESS anyway (tazer saves my setting) but hearing the Jeep may not start is scary, especially since I turn off the engine while wheeling far away from anything.

 

[AndySpill]

It sounds like I should work on this myself. My ESS hasn't worked in 8 months or so, I assumed the Aux was just toast and I don't use ESS anyway (tazer saves my setting) but hearing the Jeep may not start is scary, especially since I turn off the engine while wheeling far away from anything.

IMHO, for those with dual AGM battery JLs who have made the decision to not run ESS events, the benefits of disconnecting the Aux battery and bypassing it, a remarkably easy process, where it can no longer risk cannibalizing the main battery if it goes bad, are so, so outweighed by the extra amp hours of keeping this secondary battery connected in parallel.

Assuming that @THAW is correct, and paradoxically, the thing that does this "battery in" are its running of ESS events, and that it is far more reliable a battery when merely connected, but no ESS events are run, there is still the reality that if you don't need this extra amperage, why keep something connected that can become not simply defective with time, but take out the main battery with it if it does.

I have no horse in this race. I run ESS events with dual AGM batteries and trickle charge by solar panels on my roof rack.

 

[THAW]

Assuming that @THAW is correct, and paradoxically, the thing that does this "battery in" are its running of ESS events, and that it is far more reliable a battery when merely connected, but no ESS events are run, there is still the reality that if you don't need this extra amperage, why keep something connected that can become not simply defective with time, but take out the main battery with it if it does.

There's nothing "paradoxical" about the concept batteries age faster under heavier use; forum ESS battery mythology creates cognitive dissonance around this basic, scientific fact.

 

[churlk]

It looks like I have three different things attached here. One set of wires and two cables. Should I remove the first two (wire and top cable) leaving the mother attached to the negative?

 

[THAW]

It looks like I have three different things attached here. One set of wires and two cables. Should I remove the first two (wire and top cable) leaving the mother attached to the negative?

I don't see an AUX (ESS) battery ground cable in that picture.

 

[Rhinebeck01]

It looks like I have three different things attached here. One set of wires and two cables. Should I remove the first two (wire and top cable) leaving the mother attached to the negative?

I don't see an AUX (ESS) ground cable in that picture.

Pic he posted is poor poor in regard to angle... but it appears he / @churlk has etorque... and you know as I do, no Aux battery.

Here is a better pic of an etorque equipped ..

 

[churlk]

Pic he posted is poor poor in regard to angle... but it appears he / @churlk has etorque... and you know as I do, no Aux battery.

Here is a better pic of an etorque equipped ..

The top one on the negative is not the aux? I think the bottom one is from the rockslide powersteps. (I just bought this jeep so I am trying to figure out what this person messed up so I can fix it)

 

[churlk]

The top one on the negative is not the aux? I think the bottom one is from the rockslide powersteps. (I just bought this jeep so I am trying to figure out what this person messed up so I can fix it)

I do have etorque but what do you mean that I have no Aux? 100% I have an aux battery.

 

[Terrymo]

I do have etorque but what do you mean that I have no Aux? 100% I have an aux battery.

Most of the time, the smaller battery in the fender well is referred to as an auxillary, start/stop, or ESS battery. If you don’t have that, the 48 volt battery under the Jeep is commonly referred to as the etorque battery. If you have an etorque battery under the Jeep, you still have an empty auxillary battery box in the fender well.

 

[AndySpill]

There's nothing "paradoxical" about the concept batteries age faster under heavier use; forum ESS battery mythology creates cognitive dissonance around this basic, scientific fact.

I don't disagree with battery facts that this smaller battery has the additional uphill battle of supplying power, unlike its main battery older brother (barring engine cranks) without the aid of an alternator simultaneously backfilling power lost energizing appliances, during ESS events, and that such load applies strain.

Then again, I would hope that the voltage threshold for early termination of ESS events would be high enough that degradation of this battery would be faster, but not considerably faster than the main battery. And I suspect that there have been enough people out there who have gotten burned by simply getting Aux batteries that have not been well built. There's just too many stories of people with dual AGM battery JLs whose ESS stopped working during the very initial stages of ownership. And for this reason it has me believe it's not worth it too keep this battery connected for most dual AGM battery owners already deciding to turn ESS off.

I think you missed that which I intended as paradoxical: not battery science but that the proximal cause of the ESS battery's demise being the very thing it was installed into the vehicle to do: provide power during ESS events.

A better (albeit more expensive) mousetrap would have involved dual equal sized batteries, periodically swapping function as main and ESS battery no less, to equalize MTBF.

 

[Heimkehr]

It

looks like I have three different things attached here.

Those outboard wires -- one with loom, one without -- appear to be post facto additions. If you're not the original owner (and we'd guess you're not?), you'll want to confirm their function/purpose before proceeding here.

 

[Jammer]

What are the pros taking the AUX battery out ? I have been told by several people that run a very good off-road shop got to be came with it you need it that it can your big battery can drain quicker when you're parked for several days. They say that it's there for a reason besides the auto start stop feature and your auxiliaries. Something about it helps charge the big battery without it you're going to have problems people have had that you're better off running too big batteries then just the one big battery I mean they put it there for a reason I think more than just the auxs features and start to stop that's what I was told by people that run their own shops and they're very educated them can work on anything when it comes to trucks and jeeps I don't know. I hate to do it and have problems down the road some people have codes on the dash but it helps charge the big battery is that not true ?

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