Stinking, Stupid, Gladiator Rubicon Auxiliary Battery

[sharpsicle]

AND.... I'M FROM THE GOVERNMENT... I'M HERE TO HELP YOU... BWAHAHAHAHAHA. Mine is my daily driver the start stop is rarely ever working. Always says unavailable. Why put in cheap dealer batteries. I replaced with better quality and dont have to worry about dependability.

You ok? I’m genuinely concerned at this point…

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[Zachanadandy]

The biggest problem is running 2 different sized batteries in parallel off 1 charging system. Their charge/discharge rears aren't the same. That's why either one beginning to fail quickly kills them both. I'd have no problem with the 2 battery design if they were the same size. When it comes time for replacement the aux will get cemetery for that reason, unless I can stuff a full sized battery in its location.

 

[Panthers65]

The auxiliary battery will last as long as the main battery if things are taken care of - kept charged. The chances of the main going are the same. They live connected together save for fractions of a second when the vehicle is started, then when the vehicle restarts after an ESS stop. Otherwise, they are paired together so there's really nothing that's likely to kill the "aux" battery more than the other.

I don't think the aux battery is the devil everyone thinks it is, but I do question its true usefulness compared to the increased complexity. I've got a max tow so a bit larger battery from the start, I keep all my accessories on switches/relays to there's rarely any additional draw, and all my electronics are factory. With the larger battery/alternator, unless my main batter is dying, I don't see a situation where there could be a continued low voltage issue that would continue long enough to damage any of the factory electronics. At least not a situation that is different than the millions of other single battery vehicles over the last 50 years.

If it's $600 for both AGM batters, or $600 for a single, slightly larger/higher capacity, main battery, I'd feel more comfortable with a single battery system. A single point of failure for me will always be better than 2 points of failure unless that 2nd point is providing some sort of additional benefit.

 

[sharpsicle]

I don't think the aux battery is the devil everyone thinks it is, but I do question its true usefulness compared to the increased complexity. I've got a max tow so a bit larger battery from the start, I keep all my accessories on switches/relays to there's rarely any additional draw, and all my electronics are factory. With the larger battery/alternator, unless my main batter is dying, I don't see a situation where there could be a continued low voltage issue that would continue long enough to damage any of the factory electronics. At least not a situation that is different than the millions of other single battery vehicles over the last 50 years.

If it's $600 for both AGM batters, or $600 for a single, slightly larger/higher capacity, main battery, I'd feel more comfortable with a single battery system. A single point of failure for me will always be better than 2 points of failure unless that 2nd point is providing some sort of additional benefit.

I’d read back through the thread if you aren’t sure why the aux battery is there and the benefit it provides during ess events.

 

[Panthers65]

I’d read back through the thread if you aren’t sure why the aux battery is there and the benefit it provides during ess events.

done so and I've addressed the benefit outlines. The aux batter is there to keep voltage from dropping too low during ESS events. My statement is a battery with proper capacity would accomplish the same task and remove a point of failure.

If it was a true dual battery setup and one battery could work to back up another in the event of a failure, that'd be one thing, but that's not the case.

 

[salvino]

Never ceases to amaze me how so many jump to the conclusion, often incorrect, that the aux battery is the cause of global warming, inflation, insurance costs, hurricanes in Florida and your Jeep's electrical issues - all without any testing (and all because "the internet said so)

I'm heading on 3 years with mine - both batteries are fine, including the aux battery. ESS works perfectly after all of this time.

Maybe it's because I keep the batteries charged even though the truck may sit for almost a week at a time?

I'll repeat this since there's still a lot of 'but the internet said so' going on:
Go look at the 4xe forums out there - not associated with these or the Wrangler forums. What's the big talk of electrical issues? the batteries failing.
No, not the big HV batteries, but the 12v batteries.
What's one of the clues? Aux switched unavailable.
Now most members here would jump and say "obviously your aux battery is failing".
Yet - there is no aux battery on a 4xe. They have only one and it's the exact same battery as our JT main battery.
Another mistake too many make is believing that the aux batter handles the aux switches or ESS or whatever.
Also incorrect.
Both batteries are connected in parallel at almost all times.
Auxiliary means just that and it's a sad coincidence that both those switches and that small battery have the word "auxiliary" in front of them. They are in no way connected to each other.



Again - it could be EITHER battery - do not assume. I happen to be really observant and do watch voltage here and there. I watch for how long the battery voltage stays up during an ESS stop (but if you shut that down, then you can't use that as a tool)
Things that lead to short battery life - of BOTH batteries, and they are tied together 99.9999999% of the time, are infrequent drives, drives shorter than 30 minutes even if you do drive fairly frequently and so on.
Modern vehicles drain batteries down. And driving to work and back for most people isn't always enough to keep them up. So if you don't drive regularly, or do mostly short drives - a battery tender, such as "BatteryMinder" or similar is a good idea.
Why do the battery delete?
The auxiliary battery will last as long as the main battery if things are taken care of - kept charged. The chances of the main going are the same. They live connected together save for fractions of a second when the vehicle is started, then when the vehicle restarts after an ESS stop. Otherwise, they are paired together so there's really nothing that's likely to kill the "aux" battery more than the other.

OF all of the Jeeps we've owned with these systems, including Grand Cherokees and my 2 JTs, only once did we have battery failure. And then it was 35 months from new. It was my wife's Grand Cherokee at the time and it sat sometimes 1 or 2 weeks at a time (and silly me never bothered to keep a battery tender on it so really I blame myself)


You don't have to remove the tire and liner. Several here have done it. There are videos out there showing how to get to it without all of that - from the side behind the tire, not fully removing the liner.

My biggest issue with the aux battery is that (and I was told this by a service tech at the dealership) once the aux battery is drained low enough to cause the alert, the only way to recharge it properly is to access it directly and put a charger on it. He said, you can’t recharge it through the main battery. This makes sense as once the main is charged the charger will go to a maintain mode and not finish charging the aux.

This means if you ever let the truck sit too long without running it extensively or having a charger attached you will have to access the aux and charge it directly. Accessing the aux battery is a pain in the you know what, any way you look at it.

If they made it so you could charge it separately easily it would likely eliminate many of the complaints.

 

[ShadowsPapa]

My biggest issue with the aux battery is that (and I was told this by a service tech at the dealership) once the aux battery is drained low enough to cause the alert, the only way to recharge it properly is to access it directly and put a charger on it. He said, you can’t recharge it through the main battery. This makes sense as once the main is charged the charger will go to a maintain mode and not finish charging the aux.

This means if you ever let the truck sit too long without running it extensively or having a charger attached you will have to access the aux and charge it directly. Accessing the aux battery is a pain in the you know what, any way you look at it.

If they made it so you could charge it separately easily it would likely eliminate many of the complaints.

Actually the tech isn't necessarily correct. A lot depends on the resistance of the wires connecting the two batteries - or circuit resistance.
Since the batteries are in parallel, all else being equal it will charge like one larger battery.
You can charge it that way, absolutely. Have done it many times with multiple battery setups on tractors and other equipment as well as Jeeps.
The problem with his thinking is that in parallel, you don't see the 12.7 volts of one battery, you see the number between - 12.7 on one and 12.0 on the other, the charger isn't going to read at 12.7.
When two batteries with different open circuit voltages are connected together in parallel, current will flow from the battery with higher voltage to the battery with lower voltage, until the batteries are equalized.
So technically, until one battery reaches 12.7, the other can't be at 12.7 either.
If you check the voltage at the main battery - you are reading the voltage of two batteries in parallel. One can't be at 12.7 unless the other is also at 12.7
How the charger behaves will be up to the charger - mine does it just fine.

 

[primethios]

2020 Overland. My aux lasted about 12-18 months before I started getting the auto stop-start messages about being disabled battery charging but I still get the pit in my stomach when the thing shuts off because it feels like the truck just died in the middle of the road (too many bad memories of junkers when I was younger). Drove like that for another couple years and then I started getting a message that the aux buttons were disabled due to low power. If I made a couple hour drive there would be enough "temporary" power from charging to have all the battery messages go away but would return the next morning. Those are your two main indicators from everything I have read. The batteries are in parallel so when the aux starts to fail or is low it pulls power from the main but because the batteries are of different capacity it opens many potentials for oddness to occur with the main downside being the power draw on the main battery when the aux is discharged or failing. This is why you have to unhook the main to replace the aux. Originally it was incorrectly marketed as this battery was just for the auto stop-start but it is actually supposed to be there to run the electronics (radio, computer, usb, etc) during the stop-start cycles to maintain voltage and prevent reboots or shutdowns. Starting a couple months ago I began getting all kinds of odd gremlins with the worst being USB, radio, android auto related. I actually fried a usb flash drive and then my phone would connect/disconnect every 2-3 minutes and the radio (I have the larger 8 inch screen previous to the big wide screen on the newest models) would have a large box that took over the screen saying error/device not supported etc. Then this started happening with nothing plugged into any USB. This would even cause my phone to drain battery twice as fast because of the plug/unplug electronic effect which was a real pain when this started 1 hour into a 7 hour drive home. Radio got stuck in what I assume was a failed update from sirius or something as it would go through some sort of "subscription" screen for an extended period after every vehicle start. Because of the worsening issues and the likely strain on the main battery I replaced both batteries because of the posts of many people having no luck with the battery delete. I like the idea of the Genesis system with the relocated aux battery but the cost of it I cannot justify for my wants/needs. I went with the "through the fender" because I was concerned of tearing something up on the fuse block. Advanced Auto had the batteries in stock so I replaced both and put in the larger main battery since I had everything apart and was at the 4 or 5 year mark anyways. My biggest issue was I decided to do it on a day that was about 7 degrees outside and I have some nerve damage in my one hand so I stopped twice to warm up because trying to work upside down with short cables and trying not to arc things out was goofy. If I do it again it won't be "as bad" now that I have a feel for the job but why they thought mismatched size batteries and wedging one in a non-accessible place is just poor design in order to meet the federal requirements by 2025 or whatever the drop dead date was. A larger single battery would have probably done the trick or they could have put in a separate battery in a reachable location. They could have even done a non-agm battery, for off gas reasons, and potentially mounted it inside the truck in the storage bin or to the side of the glove box, or something like the Genesis system with a bracket. With just a bit of finagling I am fairly confident they could have mounted the battery in the tray right next to the main battery since the aux is so small. If it weren't for the fact lithium batteries can have issues in cold weather a portable usb battery bank could probably run the electronics during the stop-start cycles.

 

[Pismo61]

Actually the tech isn't necessarily correct. A lot depends on the resistance of the wires connecting the two batteries - or circuit resistance.
Since the batteries are in parallel, all else being equal it will charge like one larger battery.
You can charge it that way, absolutely. Have done it many times with multiple battery setups on tractors and other equipment as well as Jeeps.
The problem with his thinking is that in parallel, you don't see the 12.7 volts of one battery, you see the number between - 12.7 on one and 12.0 on the other, the charger isn't going to read at 12.7.
When two batteries with different open circuit voltages are connected together in parallel, current will flow from the battery with higher voltage to the battery with lower voltage, until the batteries are equalized.
So technically, until one battery reaches 12.7, the other can't be at 12.7 either.
If you check the voltage at the main battery - you are reading the voltage of two batteries in parallel. One can't be at 12.7 unless the other is also at 12.7
How the charger behaves will be up to the charger - mine does it just fine.

When I put my battery tester on the main battery it reads over 1000(760 main and 200 aux), cca. That is with both battery's in parallel would net.So what you are saying makes sense.Check separate is around 760 and 200 cca or so.

 

[Geoarch]

The odds are high that the Main Battery is the problem and the new Aux Battery is keeping the system going. If you do not also replace the Main Battery, you will soon have a repeat of the problem.

The Aux Battery is tested at every startup. If it fails the test, you get a red A symbol and a ESS disabled message. There is no test for the Main Battery, but the ESS or Aux Switches unavailable messages are the warning signs there is a problem.

The average life expectancy of the batteries is three years. If they are kept charged they will last longer, if not they will fail faster. Both batteries should be replaced at the same time and fully charged before installation.

I'm retired so don't drive every day. I put a maintainer on it if I'm not going to drive 20-30 miles or not drive for a few days. If the gauge is in the 12.7-13 range I don't worry about charging. When it gets to 14+, then I put it on the charger. The latter is usually when I only drive a few miles between charges. When I bought it new last March, the AUX died immediately. Maybe during the strike batteries sat on the shelf for a few months although I'm not sure that would do it. In any event, it was warrantied, the dealer put a new AUX battery in and I installed an Odyssey. No problems so far.

 

[Geoarch]

That statement is just wrong and ignorant on so many levels.

The biggest problem is the vehicle not being driven enough to keep the batteries charged.

The Jeep OEM batteries are not the highest quality available, but they are adequate. Jeep has had issues with batches of defective batteries. Dealers will let the vehicles sit on the lot for months with discharged batteries, which leads to early failure. It is a major inconvenience, but Jeep will replace the batteries under the 3/36 warranty when they do actually fail.

Yes. See my comments. On my 2024 JTR I bought last March, the AUX went out the first week. Jeep replaced the Aux and I replaced the main with an Odyssey. I use a maintainer if I don't drive it any distance (see Shadows Papa comments).

 

[KX L]

I do two things when I start my MT JT:

1. Turn the ESS off with the button on the center dash under the volume control knob.

2. Turn on my lights. With the number of distracted drivers wandering around I want to be sure I can be seen from all sides. Even though the sun is directly behind me and bright as can be you should note my cove lights right under the M that are tied into my turn signals. Amazingly bright amber flash when I'm turning.

 

[John7595]

Genesis dual battery fixed all my issues. Haven't had any problems since.

Do you still need the aux battery with this setup?

 

[RJH9701]

Hi...

Sav_Gladiator said:
Genesis dual battery fixed all my issues. Haven't had any problems since.

The Geneis set up is super slick. Thx for showing. Does it eliminate the AUX batt?

 

[Sandman 4x4]

Genesis dual battery fixed all my issues. Haven't had any problems since.

Wow so you mounted two full sized premium batteries, I would imagine wired up like the originals, just matching sized instead of one motorcycle sized?

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