Has anyone done the Aux Battery delete like this?

[ShadowsPapa]

The only real purpose of the aux battery as mentioned above is to power the radio, fan, etc while the truck is in auto stop mode, leaving the main battery free of that load to handle the restart.

EHPS and engine cooling fan, among some other things, are still powered by the main battery during an ESS stop event.
During a stop, the main battery isn't far behind the aux battery in dropping voltage.
I have watched the voltage of both batteries during an ESS stop - the main drops fairly fast, too.
Schematics prove that some things are connected directly to the main battery, cooling fan and EHPS are at least two of them.

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[Camaroboi13]

The AUX will cannibalize the primary battery when it starts dying, and your supersmart Jeep with its 8,000 sensors and warning lights wont' tell you it's doing until you get hung out to dry somewhere inconvenient.

I’ve been waiting on that for over 5 years in my wife’s JLU, it’s always said not ready/charging since the day we bought the Jeep new. In 5 years of ownership, the ESS has worked less than 10 times, always charging it says. It should have cannibalized the crap out of the factory main battery that’s never been replaced by now…

 

[j.o.y.ride]

EHPS and engine cooling fan, among some other things, are still powered by the main battery during an ESS stop event.
During a stop, the main battery isn't far behind the aux battery in dropping voltage.
I have watched the voltage of both batteries during an ESS stop - the main drops fairly fast, too.
Schematics prove that some things are connected directly to the main battery, cooling fan and EHPS are at least two of them.

fine.

but the main point of 'why not retain the aux battery' is, at least for people with ESS off, the ongoing replacement costs and time.

'I enjoy a good headache every 2-3 years that I get to spend labor and $100 parts on for something I get zero use out of'.

 

[Lunentucker]

Weird how my 2019 Subaru does all of this stuff with one battery, AND sometimes I walk by it in the garage and can hear the fuel pump running while it's doing self-diagnostics and emailing me the report. ... and yet it somehow still starts right up with the four year old battery. ?

 

[Lunentucker]

I’ve been waiting on that for over 5 years in my wife’s JLU, it’s always said not ready/charging since the day we bought the Jeep new. In 5 years of ownership, the ESS has worked less than 10 times, always charging it says. It should have cannibalized the crap out of the factory main battery that’s never been replaced by now…

Southern CA doesn't get a lot in temperature swings. Good for you!

 

[Camaroboi13]

Southern CA doesn't get a lot in temperature swings. Good for you!

Of course we don’t …

 

[ShadowsPapa]

fine.

but the main point of 'why not retain the aux battery' is, at least for people with ESS off, the ongoing replacement costs and time.

'I enjoy a good headache every 2-3 years that I get to spend labor and $100 parts on for something I get zero use out of'.

If I were to disable ESS - like with Tazer or the autostop delete device, I'd remove the battery - why keep the weight in there, the chemicals of a battery, etc.
Pull it out.
I'd leave all wiring - no reason not to, but leave a disconnected battery in there that will lose capacity just sitting, making it worthless in a few months anyway?
It's not going to be a spare battery if that's what they are thinking. It will die - and be worthless in weeks or months. Why keep it?

For those who disable ESS all the time - Tazer or other device, it's totally illogical to leave the battery in there. It's a brick. It won't be any good in the future anyway.
Put it in your lawn tractor.

 

[ShadowsPapa]

Weird how my 2019 Subaru does all of this stuff with one battery, AND sometimes I walk by it in the garage and can hear the fuel pump running while it's doing self-diagnostics and emailing me the report. ... and yet it somehow still starts right up with the four year old battery. ?

Go visit any Jeep forum - the common theme "Jeep batteries suck" and they are talking even non-ESS vehicles. Jeep batteries are short-lifers. All of 'em. The forums out there are full of that.
I even see that comment come up almost weekly on the 4xe forums. "Jeep batteries suck".
So it doesn't really matter, ESS or not.

 

[Lunentucker]

Go visit any Jeep forum - the common theme "Jeep batteries suck" and they are talking even non-ESS vehicles. Jeep batteries are short-lifers. All of 'em. The forums out there are full of that.
I even see that comment come up almost weekly on the 4xe forums. "Jeep batteries suck".
So it doesn't really matter, ESS or not.

Thus the sheer genius of designing a vehicle that's always on and burying yet another crappy lawn mower battery under the fuse box and behind the fender liner to make up for it ?

 

[ShadowsPapa]

I’ve been waiting on that for over 5 years in my wife’s JLU, it’s always said not ready/charging since the day we bought the Jeep new. In 5 years of ownership, the ESS has worked less than 10 times, always charging it says. It should have cannibalized the crap out of the factory main battery that’s never been replaced by now…

That's right. It won't necessarily do that. And it happens the other way around just as easily - main battery goes bad, aux battery is fine.
Too much BS out there. People believe the mis-information stupid-highway bunk put out by people that can't even read a wiring diagram - but they are sure battery experts.
ESS not working, battery charging, can happen if it's not driven often enough and/or for long enough.
I bought my 2022 last July. ESS has always worked, always. Once I get 1.5 miles from home, the engine coolant is up to temperature, as long as the cabin temp has been reached, ESS works.
On the other hand, the 2021 Grand Cherokee my wife had before trading for her purple Jeep a month ago - it sat for a week at a time. There were times it sat for over a week. And maybe she'd drive it 30 minutes. ESS didn't work very often. It worked if she drove it to several stops - put a good hour of road time on it, then it would be ok.
But the sitting unused for days at a time all caused the batteries to be too low for it to work. 12.4 volts is the threshold for some years.
And an alternator is NOT a battery charger. It's a maintainer, and will top off a battery that's only a little low, but it's not going to charge a battery sitting at 12.2 volts in 45 minutes. Just won't happen. The alternator is more of a trickle charger - it's main purpose is to operate the truck's electric system, not to charge a battery (and it takes a lot more to charge 2 batteries)

Thus the sheer genius of designing a vehicle that's always on and burying yet another crappy lawn mower battery under the fuse box and behind the fender liner to make up for it ?

Interesting to note that those who have done battery replacements and buy quality batteries - end up not having so many problems. Supporting the idea that Jeep batteries suck.

They'd be fine with GOOD batteries and if driven at least every-other day for more than 30 minutes.
Owners are the biggest enemies of batteries, IMO. (Jeep batteries make it even worse)
You can replace that small battery without doing any more than pulling a couple of plastic retainers, folding back the fender liner, and getting the battery pulled out. You don't need to actually remove anything - not the fender liner, nothing. It's a lot easier than people make it out to be. Too many make it harder work than is necessary.

 

[Lunentucker]

Jeep doesn't make batteries, and I seriously doubt that they would be so stupid as to design their own batteries, as opposed to having a knowledgeable and experienced maker simply slap their labels on something they're already doing well.
Johnson, Exide, East Penn.

Misplaced logic and "Internet hype" might easily conclude that since batteries in Jeeps are notoriously short-lived, then certainly Jeep batteries are poor quality, overlooking the elephant in the room, that maybe the Jeeps themselves are making the batteries look bad.

 

[Almost]

I only purchase batteries made by East Penn specifically the Deka brand (can be found at Napa). They seem to be the best among the 3 main battery manufactures. If I had to guess the AUX is probably made by Johnson Controls given the issues they seem to have.

 

[sharpsicle]

Holy crap there are a ton of bad assumptions going on in this thread!

First, battery quality in Jeeps is bad. No, it's not the Jeep doing it to the battery. Mopar just isn't forking over for high-quality batteries. Period. Nobody is saying Jeep makes the batteries, just that they use cheap shorter-life ones.

Second, one bad battery in parallel will not automatically kill the other. The other may drain quicker, now that the system's overall capacity is diminished, and sure it could possibly drain abnormally fast due to a faulty condition in the other battery. But it's not a guarantee. Far from it in fact. The main could "kill" the AUX battery just as easily. But chances are it isn't, just like chances are the AUX isn't killing the main.

Third, either battery being on its way out will display symptoms and warnings before it's too late. There are monitoring systems and start-up tests that look for exactly this. Usually, they're ignored, and then when the system has finally had enough, the owner goes "I had no idea!". Yes, you did. Ignorance of warning signs doesn't make the failure a surprise.

Fourth, if your Jeep is giving the indication that ESS is unavailable due to battery charging, or that AUX switches are unavailable for the same reason, that is absolutely not proof that the AUX battery has failed. These warnings are more often associated with the main battery's charge state. Don't just assume it's one or the other. Check each one, and correct the issues that you find. These indications on the dash screen are not a substitute for troubleshooting.

(And since it's a common misconception, there's no connection between the AUX battery and AUX switches. They are independent auxiliary systems.)

Fifth, a dead AUX battery will not prevent you from jump starting the truck. More needs to be wrong for that to be an issue. It's not just the AUX battery's fault. See point 3 above.

I know it's easy to just blame the AUX battery for all these things, but it just isn't the truth.

 

[ShadowsPapa]

Jeep doesn't make batteries, and I seriously doubt that they would be so stupid as to design their own batteries, as opposed to having a knowledgeable and experienced maker simply slap their labels on something they're already doing well.
Johnson, Exide, East Penn.

Misplaced logic and "Internet hype" might easily conclude that since batteries in Jeeps are notoriously short-lived, then certainly Jeep batteries are poor quality, overlooking the elephant in the room, that maybe the Jeeps themselves are making the batteries look bad.

Yes, we know they don't make filters, oil, batteries, bulbs, or many of the other small items that make up the vehicle. Wasn't long ago they didn't make their own wiring harnesses, and I can't prove that even today, they do make them. Coleman made them up until at least the 1990s.
Bet they don't even raise their own cattle for the leather.
It's like saying "Ford floor mats" - made FOR Ford, sold by Ford.
Take a loot at the content of any vehicle. Smaller items almost always outsourced.
In fact, Jeep didn't even make the frame under your truck. They didn't make a lot of stuff.
Chevy brakes - probably made by Kelsey-Hayes. Jeep front hubs - Kelsey-Hayes at least into the 1990s. Chrysler brakes - again, likely Kelsey-Hayes. Wheels - same.
These days Jeep is more like a general contractor - pulling together parts from other sources to make the vehicles they designed. So often, Jeep has things made for them.

 

[ShadowsPapa]

I only purchase batteries made by East Penn specifically the Deka brand (can be found at Napa). They seem to be the best among the 3 main battery manufactures.

I typically try to buy NAPA's best batteries these days. The battery in my 73 Javelin came from NAPA 8 years ago. The car sits a LOT, I mean a LOT. No parasitic draw of course other than modern radio, but it's still a good battery. It's a 5 year battery if I recall.
NAPA batteries are USA made in Pennsylvania if I recall correctly.
And if my JT batteries, either of them, die - if in warranty, let Jeep pay for it, if after, I'll go to NAPA.

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