ESS Battery Dead?

[shadango]

I completely agree, and yet, interesting enough, my finger is more pointed at the EPA than Stellantis here, and so you should know my biases I am an environmentally leaning person who believes in the EPAs mission.

That said, and to keep me off my soapbox, the CAFE rules for automobile manufacturers to be able to advertise their best mileage ratings incentivizes an ESS system in the JL that is more designed to pass a one time EPA test than our daily driving. The rules need review.

Stellantis could of course design a better ESS system, but we'd end up paying for it in part in purchase price. They didn't want to go with a one battery ESS system like so many other manufacturers because, I suspect, owners tend to add power hungry appliances that could rob a sole cranking battery.



Again, your sentiments resonate well. I was contemplating stocking a backup ESS battery as a result of hearing things like what you've said above. A couple of thoughts. There are some excellent posts (links available on request) that detail the 3rd party batteries, both main and ESS ,that you can purchase--not that you should have to.

I'd suggest that you chat with @JeepCares on this one (now) so as to guarantee that potential battery defects that occur in the warranty period are handled gratis after that window of time if MOPAR parts to rectify the issue only became available after that window.

Let me get more philosophical about your question regarding what Jeep expects us to do.

Love my Wrangler though I do, aspects of the vehicle have been allowed to fall short in terms of included and/or add on MOPAR equipment because of historical limited competition in the vehicle space and the realization that such shortfalls are addressed by the aftermarket in better and cheaper product. For this reason alone I welcome the competition that Ford's rollout of the redesigned (not so) new Bronco brings.

Another aspect of the Jeep community that has been expected of us lies in the Marine's motto of "improvise, adapt, and overcome." We shouldn't have to but we do. And if I were managing a team faced with this famous American problem, I might be inclined to ask initially ask, "ok, who among you engineers owns a Jeep." Those would be my guys and gals who know how to put a square peg in a round hole if necessary, to solve a problem.





The EVIC display of voltage, I believe, serves two useful functions. The first, during non-ESS events tells me how hard the smart alternator is working to replenish power that's been drawn from the batteries. As a smart alternator, it will demand less of the engine (read gasoline) in times when the batteries are charged and/or are charging well (i.e. accepting charge well.) While I own a 3.6L, that 14+ voltage reading your referring to would lead me to have each battery independently load tested., as it seems to be a high voltage reading.

As you are probably aware, load testing gauges how well a battery does that very thing it needs to do: accept and deliver charge.

The second use of the EVIC allows me to watch the ESS' batteries voltage during ESS events. At such times it is only this battery's voltage that the EVIC displays.

To rephrase, a high EVIC voltage reading during non-ESS events more symbolizing to me a need to load test batteries, not some point of pride in how well my alternator is working.



Sadly, no advance notice warning is expressly communicated to the operator by the vehicle of impending doom. We look for signs like a slower crank, electronics acting squirrelly, but no.

That said there are some things you can do. At the most orthodox end of the range lies a system the Godfather of JL battery knowledge Jerry (@Jebiruph) set up to monitor each battery's voltage https://www.jlwranglerforums.com/forum/threads/ess-dual-battery-management.60034/

This link comes from a posting of most of his important battery findings found here:

https://www.jlwranglerforums.com/forum/threads/3-6l-ess-dual-battery-consolidated-information.25377/

And included at the aforementioned link is one where he talks about how to load test the batteries.

https://www.jlwranglerforums.com/forum/threads/3-6l-ess-battery-basic-load-testing.22031/

This stuff can be a lot of work or not so much depending on how much someone wants to monitor their batteries.

In a simpler version I have one of these on my main battery's negative terminal, upon which the negative from the ESS battery is connected.

https://www.amazon.com/gp/product/B07JZ9NDH2/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

When this knife switch is in the open state, putting a battery tester on the main battery will give you a reading of only the main battery. If the switch is closed the reading is a composite of both batteries which often gleans limited information.

Again with the knife switch open, moving the negative terminal of tester to the cable attached to this knife switch, whose origins are the negative terminal of the ESS battery, will give you a reading of the ESS battery.

That's right....even though your positive tester lead is still on the main battery's positive terminal,, it's the ESS battery that is being tested.



Me too. And yet I wouldn't be surprised if it doesn't help. Here's why. Your plan diverts all calls for electrical current to only the main battery. Unfortunately if the ESS battery has, due to defect, cannibalzed the main battery to limited voltage, you may not crank.



I'd be inclined to say that an otherwise healthy main battery that has been depleted of power by a defective ESS battery--at least for the first few times this happens, will likely be able to accept the charge of your jumper and still have useful life going forward.

FWIW your plan sounds very similar to something I'd do.



If the desire to run ESS events really isn't your thing, IMHO the ESS battery is more a hinderance and should be taken out of the vehicle's electric schematic than kept. (Conflict of interest statement: I run both batteries and trickle charge while parked. See above about my environmental guilt @ gasoline.)

That said, let's address the ESS off light. This is best done by running through exactly what happens at cold crank on a dual AGM battery JL.

When you press that brake and start button one of the first things your dual AGM battery JL is going to (try to) do is isolate the ESS battery to test its voltage. It will do, or attempt to do this by energizing a relay that separates the batteries--otherwise the batteris are always connected in parallel but for this instant, and during ESS events.

If Fuse 42 is pulled this relay cannot get electrical current and fails (to separate the batteries) without so much a of whimper. Your JL then "tests its ESS battery" or so it thinks--which because the relay is dead, turns out to be all the batteries that are connected--which in your case is only the main battery.

You have tricked your JL into thinking that your main battery is both your main and ESS battery.

Provided that your main battery has adequate current, the ESS off (in the dash---I'm not talking about the one on the ESS off switch below near the radio) light shouldn't illuminate in the dash and the JL should crank. I encourage you to turn ESS off with a button push or aftermarket tech. Running ESS events with one battery depletes that battery of cranking power at the end of the ESS event. Sure, plenty of vehicles run ESS with one battery and it isn't usually the end of the world if you forget, but the "perfect storm" of an aged main battery running an ESS event at a traffic light, while your aftermarket sound system and lights that could "land a plane" are drawing major current could leave your ability to re-crank the engine and get the alternator going compromised.

Let's talk about another scenario. This one involves merely disconnecting the ESS battery's negative cable from the main battery's negative terminal and stopping. No Fuse 42 pull, no N1 to N2 fused jumper. (The latter was the original technique to insure the batteries are always in parallel.)

Now, since you are NOT running an early model 2018, your initial attempt to cold crank will fail (only the first time) because no ESS battery was found when that relay was energized. But the second attempt to cold crank, and those thereafter will be against only the main battery. If it is successful, in this scenario the ESS off light in the dash (i.e. EVIC, not the light on the button) will illuminate.

Your JL is saying, "I'm not allowing ESS events because I detected no current on the ESS battery."

Forever more your cold cranks should work on the first try going only against the main battery, and illuminating that ESS off light in the dash. No aftermarket tech to turn off ESS is needed; no push of the button. But some people hate this ESS off light in the dash, in which case I recommend the additional Fuse 42 pull to trick the vehicle, with operator involved turning off of ESS (button push, aftermarket tech, etc.)

Only the cold crank after an energized ESS battery is reconnectted, if ever, will that ESS off light be turned off.



IMHO there is not. Even if that battery's casing were to be compromised over the years, it sits closest to the ground with no vehicle components under it to corrode from acid spill.

Some forum members like to keep that ESS battery independently charged. Again, this is easiest done by putting your charger's negative side on the dangling cable you disconnected and the positive side on the main (that's right, I said main) battery's positive terminal.


I change my JLs batteries every 3 years. I wish their MTBF (mean time between failure) metrics were better.

Fudster, again...THANK YOU!

I think I will just disconnect that negative going to the ESS battery first and try stuff. I would rather "kill" the ESS babttery before it kills my main battery and makes it UNJUMPABLE. What a design!

I have heard that tinkering with this system , if there is a light on the dash, will result in remote start being disabled.....so I may have to also pull that #42 fuse so the light doesnt light and so I can remote start....and live with manually pressing the ess system button "off" every time or buying a taser.....am i getting that right?

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[Fudster]

Fudster, again...THANK YOU!

I think I will just disconnect that negative going to the ESS battery first and try stuff. I would rather "kill" the ESS babttery before it kills my main battery and makes it UNJUMPABLE. What a design!

I have heard that tinkering with this system , if there is a light on the dash, will result in remote start being disabled.....so I may have to also pull that #42 fuse so the light doesnt light and so I can remote start....and live with manually pressing the ess system button "off" every time or buying a taser.....am i getting that right?

I am not certain that the presence of an idiot light on the dash will preclude remote start from working but it would not surprise me.

That said, and along your solid line of reasoning, the absence of of such idiot lights is certainly a step in the right direction to allow remote start to work, and..

the method you've described of pulling Fuse 42 is a solid way IMHO to prevent that ESS off idiot light from appearing.

 

[goochman]

At the 3 3/4 year mark my 2020 Rubicon wouldnt start, however all electrical in the Jeep looked fine (no dim lights, etc...). Jump start worked and took to dealer - both batteries tested and needed replacement. Looking online I didnt want to fuss with taking the TIPM out to replace the ESS battery (who designed that!) My dealer had no problem getting a replacement battery so after paying way too much Im back on the road.

Next time this happens Im going to get an AGM battery and leave the ESS battery disconnected.

 

[linux_guy]

Can I use my Noco Genius 10
(https://no.co/genius10) to buy time and then resurrect when my 2020's batteries die? Or to delay the onset of battery death? I only have 12K miles and usually turn off ESS via the button.

I bought the fender W clips to have should I want to pull a fender when time comes. I like the idea of the Genesis. I do also have the Noco GBX155 with 4250 amps, so I have emergencies covered. I'm only slightly joking when I ask if one of those Nocos under the hood (locked with Bolt) could be a medium term solution when/if symptoms appear.

 

[beachbumm78]

That’s crazy your dealer said that. Mines dying at just under two years and I have an appt scheduled with my dealer for this next week to get the aux battery replaced under its two yr warranty. There are 3rd party batteries available for a decent price if you need that route. That was my backup.

 

[txj2go]

If you want the most reliable- buy one of these and disconnect the small battery. Don't mess with the dealer anymore.
https://www.batteriesplus.com/produ...1/rubicon/v6-3.6l-w_start=stop-gas/sli48agmdp

 

[Rhinebeck01]

If you want the most reliable- buy one of these and disconnect the small battery. Don't mess with the dealer anymore.
https://www.batteriesplus.com/produ...1/rubicon/v6-3.6l-w_start=stop-gas/sli48agmdp

Batteries+ has some real decent offerings. I would go with the Batteries+ X2 Power H7 Group 94R SLI94RAGMDP 840 CCA

A few $ more for their Group 94R versus their Group 48, but you get additional CCA.

 

[AEDRUBI]

Looking thru some threads to find a problem similar to mine…2019 Rubicon. Main battery is only a year old, in Arizona, but garage kept. The aux battery was replaced under warranty about 3 years ago. Hadn’t been cranked in 3 days, and wouldn’t start during 2 attempts…then started. Ran it over to an autozone to test battery, and it was at 99%…again, wouldn’t start at autozone on first attempt, but started ok on second attempt.

No warning lights of any kind…sat in my drive for a few hours and was able to remote start just fine. Sat overnight and all day…hit the remote and started with no problem…. Is it the aux battery?

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