Yet another ESS story

[LarryB]

Didn't need the rest after this line. Lead acid batteries slowly die when sitting in an idle modern vehicle that's constantly draining a little bit of power even when off. The Jeep's aux battery config only exacerbates the problem.

If you know your Jeep is going to sit idle for a while, put a trickle charger on it so it doesn't shorten your battery life.

I bought my 2018 (it was about 2.5 years old) with only 7000 miles on it. It had sat for a long time. The dealer replaced the aux battery, as it was fried, but did not want to replace a borderline main battery. I didn’t bother to press and just bought an Odyssey, which is what I like to have in my vehicles anyway. Anyone buying a very low-used JL should consider their batteries to be suspect and likely needing a replacement.

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[dsgrey]

You could also remove the aux battery and do the jumper bypass. I never saw a noticeable difference in mpgs with our without ESS.

 

[Rhinebeck01]

You could also remove the aux battery and do the jumper bypass. I never saw a noticeable difference in mpgs with our without ESS.

@dsgrey

Yup, install a fused N1-N2 bypass jumper, disconnect the Aux battery negative cable from the Main battery, negative terminal and that is it. Done....

Cost would be about $8-10 to do ... and any guy/gal can do this in less then 10 min.... AND... just leave the small Aux battery down in it's holder to forever sleep lets say..

I've been doing the aforementioned for years with my 3.6 JL.. Never a battery related issue, no EVIC/warning lights and or codes thrown.

YES, I use a SmartStopStart unit in order to minimize use of ESS which is prudent if you chose to run with just the Main battery.

 

[OldBlue]

@dsgrey

Yup, install a fused N1-N2 bypass jumper, disconnect the Aux battery negative cable from the Main battery and that is it. Done....

Cost would be about $8-10 to do ... and anyone can do in less then 10 min.... AND... just leave the small Aux battery down in it's holder to forever sleep lets say..

I've been doing the aforementioned for years.. Never a battery related issue, no EVIC/warning lights and or codes thrown. YES, I use a SmartStopStart unit in order to minimize use of ESS which is prudent if you chose to run with just the Main battery.

Best mod you can do to your JL right there. I've done this with 2 of our 3 Jeeps, and it works great.

 

[ZigZag]

I bought my 2018 (it was about 2.5 years old) with only 7000 miles on it. It had sat for a long time. The dealer replaced the aux battery, as it was fried, but did not want to replace a borderline main battery. I didn’t bother to press and just bought an Odyssey, which is what I like to have in my vehicles anyway. Anyone buying a very low-used JL should consider their batteries to be suspect and likely needing a replacement.

That is definitely the message I am getting. Thanks!

 

[ZigZag]

More info.
I started looking for Die Hard batteries. Sears is no longer in business and Advance Auto Parts now owns Die Hard. I don't know if the Die Hard Platinum is still the best battery on the market. It certainly isn't the most expensive. Advance offers free installation, except for Jeep JLs. They guy said something about programming the batteries. I don't know what that means and I have low confidence that this guy had any idea what he was saying. He said that there is an oil change shop down the street that could do the install for a low fee. Whatever. I would be more likely to do it myself. I figured I would give the charging thing a few days to work.
Then on Saturday the ESS started working. Every time I stopped. With very little recharge time needed to get to the Ready state. I had to park outside on Saturday and Sunday nights and did not charge the batteries.. ESS worked fine Sunday and Monday. I was shocked. I parked in the garage last night and charged the batteries. This morning the ESS is back to its old tricks. Go figure.

 

[slowpoke387]

@dsgrey

Yup, install a fused N1-N2 bypass jumper, disconnect the Aux battery negative cable from the Main battery, negative terminal and that is it. Done....

Cost would be about $8-10 to do ... and any guy/gal can do this in less then 10 min.... AND... just leave the small Aux battery down in it's holder to forever sleep lets say..

I've been doing the aforementioned for years with my 3.6 JL.. Never a battery related issue, no EVIC/warning lights and or codes thrown.

YES, I use a SmartStopStart unit in order to minimize use of ESS which is prudent if you chose to run with just the Main battery.

Just came across this and have a JLUR XR on the way. Wondering if the aux battery would actually be needed for the XR package considering the charging system that is used. Isnt the extra amperage needed to help move the 35's? I thought that was why the XR package could only be had with the aux battery setup. We def want to do this mod but not if it adversely affects take off power.

 

[Canucklesammich]

Just to clarify: it's the design not the low quality OEM batteries? Or is it simply a matter of how often it's driven to keep the batteries fully charged? Or lack of QC from the factory? Or something else?

 

[The Last Cowboy]

Just came across this and have a JLUR XR on the way. Wondering if the aux battery would actually be needed for the XR package considering the charging system that is used. Isnt the extra amperage needed to help move the 35's? I thought that was why the XR package could only be had with the aux battery setup. We def want to do this mod but not if it adversely affects take off power.

If you have the eTorque/BSG on yours, you have no chioce but to keep the 48v battery mounted to the frame.

This thread is for ESS equipped Jeeps with the small motorcycle battery under the main battery.


@Canucklesammich

Bad batteries on new vehicles seem to be a plague in the last few years. If they are stored too long and/or not fully charged before install, there will be problems. If the Jeep sits in inventory at a dealer for a few months and only gets started enough to move it around the lot, then there will be problems. I haven't read of any problems from those who have bought and installed a quality aftermarket battery/batteries.

 

[slowpoke387]

If you have the eTorque/BSG on yours, you have no chioce but to keep the 48v battery mounted to the frame.

This thread is for ESS equipped Jeeps with the small motorcycle battery under the main battery.


@Canucklesammich

Bad batteries on new vehicles seem to be a plague in the last few years. If they are stored too long and/or not fully charged before install, there will be problems. If the Jeep sits in inventory at a dealer for a few months and only gets started enough to move it around the lot, then there will be problems. I haven't read of any problems from those who have bought and installed a quality aftermarket battery/batteries.

Ah makes sense. Explains why I had't seen that mod yet lol. Thx for the heads up.

 

[Chupacabra]

Just to clarify: it's the design not the low quality OEM batteries? Or is it simply a matter of how often it's driven to keep the batteries fully charged? Or lack of QC from the factory? Or something else?

I replaced both my batteries and the ESS is still occasionally wonky. Especially if it's been sitting for a few days. I think the IBS thresholds for when to engage ESS are probably just a bit conservative and prevent it from working when there's really plenty of juice/charge in the batteries.

I have also found that if my ESS stops completely, throwing a trickle charge on overnight is enough to make it work again for 1-2 months pretty reliably.

It's just a really stupid design to have 2 batteries for ESS. None of my other cars with ASS/ESS have ever had two batteries and they worked perfectly - all the time.

 

[The Last Cowboy]

Mine hasn't worked for 6 months or more. No issues starting, even when it sits for a week.

 

[ZigZag]

I put mine on a NOCO charger periodically. Less than once per week, overnight. The ESS seems to work most of the time now.

 

[Canucklesammich]

So, another question: if I have an ESS bypass module (which I do, so ESS is disabled), is it less likely to go bad, since the small battery shouldn't be used? Or is that simply postponing the inevitable?

 

[Rico1111]

Zig Zag ....read this, very informative!
https://www.jlwranglerforums.com/forum/threads/jumperless-aux-battery-bypass.95945/

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