3.6L ESS Battery Diagram

[WranglerMan]

I'm confused too. For 9 months, my voltage was consistently around 14.5, except after extended driving when it fluctuate as designed. Then after a day or two it would return to the high voltage and over time that creeped up to 14.8. Today after reading your post, I checked for the first time in several weeks and it was 13.5 as it should be.

I think what happens is that normally the alternator voltage is monitored by, then adjusted by the Powertrain Control Module as needed, as long as there is a clean bill of health from the IBS. If data from the IBS indicates any possible issue, the PCM cranks up the alternator output until the IBS is happy. I think most of the time my IBS is not happy.

I am guessing from looking at your past posts and diagrams that the IBS is that little module on the negative main that has a connection coming off of it ? And if that’s it I wonder what it takes to satisfy the IBS so it sends the correct info to the PCM, I mean it’s a module that sits on the post and monitors voltage

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[Jebiruph]

Here's and updated version of the battery diagram based on the appearance and location of the physical components. This should help locate and
identify all physical connections discussed in various posts. I've included instructions to manually manage the batteries to run Aux only or Main only.

 

[Jebiruph]

Here's and updated version of the battery diagram based on the appearance and location of the physical components. This should help locate and
identify all physical connections discussed in various posts. I've included instructions to manually manage the batteries to run Aux only or Main only.

View attachment 210393

Added a PDF of this diagram to the first post - jumper diagram 2

 

[sstuner]

Transferred to iPhone for future use. Great info. Thank You.

 

[msandhu413]

[QUOTE="
Due to doubts I had about how the PCR worked, I went ahead bought one (PN# 56029766AC) for testing. Contrary to what I previously thought, the relay is normally closed, meaning the PCR connects the Main battery and the Aux battery when no power is applied, and seperates them when power is applied (auto stopped). I also now think it is only a relay with no battery control electronics. I was hoping it would be easy to open it up, but it's pretty well sealed with epoxy.
[/QUOTE]
question:
looking at the PCR - can you confirm which connector on the PCR is connected to the AUX battery and which is the one going to N3?

 

[cabnfvr]

If it's truly just a heavy duty relay as it appears (and the small plug is the trip current) then it would not matter which lug the N3 and Aux battery cables were connected to.

 

[Htfan]

Using a smart battery isolator was mentioned early in this thread to address the parallel batteries draining each other when one goes bad, but I don't believe I saw any further discussion.

Has anyone looked into utilizing a smart isolator between the main battery/N2 or the aux battery/N1? Or some other location?

 

[2019 JLUR]

What would if you install a bigger starting battery and just hooked up the positive and negative leads from the aux battery to the starting battery. This way you will have just one battery installed. I know you could run down the starting battery but if it large enough it could handle the load when the motor is off.

So in the Genesis installation they take the positive cable from the removed Aux battery and attach it to the positive connection of the main battery. They do not use the disconnected negative cable. So this means that you could remove the Aux battery and reconnect the positive cable from the Aux battery to existing main battery the same way they do in there installation. Am I missing something here?

 

[Jebiruph]

So in the Genesis installation they take the positive cable from the removed Aux battery and attach it to the positive connection of the main battery. They do not use the disconnected negative cable. So this means that you could remove the Aux battery and reconnect the positive cable from the Aux battery to existing main battery the same way they do in there installation. Am I missing something here?

Here's a diagram of what that looks like and a diagram with what I believe are the redundant wires removed. I haven't tried either, but have been told the Genesis version works, but the stripped wiring version causes stop/start errors.

 

[jungloewe]

hi everyone.
I have to follow up here.
So i understood the whole thing BUT one point is just not working like that for me.
Claim: you cannot charge (or unload) two batteries with different capacities at the same time.

If our alternator (or solar or charger) is loading both batteries at the same time due to the PCR the smaller batterie is getting full sooner and that wouldnt allow the big battery to get fully loaded.

More dangerous:
If you unload (because of using a compressor cooler or whatever) the smaller battery will drain full to 0 but the big one have still capacity and would reversecharge the smaller battery what definitely will damage them.

My doubt: Parallel usage is only possible with nearly the same battery type and capacity.

I hope i am wrong, otherwise it would explain some behaviours discussed here.

PS: Sorry for my english. I'm from germany...

 

[redracer]

hi everyone.
I have to follow up here.
So i understood the whole thing BUT one point is just not working like that for me.
Claim: you cannot charge (or unload) two batteries with different capacities at the same time.

If our alternator (or solar or charger) is loading both batteries at the same time due to the PCR the smaller batterie is getting full sooner and that wouldnt allow the big battery to get fully loaded.

More dangerous:
If you unload (because of using a compressor cooler or whatever) the smaller battery will drain full to 0 but the big one have still capacity and would reversecharge the smaller battery what definitely will damage them.

My doubt: Parallel usage is only possible with nearly the same battery type and capacity.

I hope i am wrong, otherwise it would explain some behaviours discussed here.

PS: Sorry for my english. I'm from germany...

You are correct. Generally accepted battery practice is that you should never parallel batteries unless they are matched (same size, type, brand, and manufacture date).
This is why I believe the the system is flawed and I bypassed the small battery by disconnecting it's negitive cable and disconnecting the PCR control leads.

 

[Dauron]

You are correct. Generally accepted battery practice is that you should never parallel batteries unless they are matched (same size, type, brand, and manufacture date).
This is why I believe the the system is flawed and I bypassed the small battery by disconnecting it's negitive cable and disconnecting the PCR control leads.

I agree with the above and it makes me wonder if this is actually 100% true that the PCR is being disconnected ONLY when the ESS kicks in. I could imagine that it might be also disconnected during the regular drive iff the system detects that the smaller battery is fully charged (not to overcharge it)?

I am about to charge my 2019 *European* 2.0 which I believe has same setup as the 3.6. It is down to ~12.2V combined after two days of not driving (I haven't checked the batteries in isolation yet). I daily drive it, but usually it is ~15miles/per day (I am not counting sporadic, longer offroad trips). I tend to also agree with the charging related opinions I have found on the other forums (see below) and plan to charge the batteries in separation so the smart charger can properly asses their individual condition. I will be using CTEK MXS 5.0 which is quite popular here in Europe (Swedish manufacturer).

https://www.jeepgarage.org/threads/...eries-while-in-storage.221577/post-2021233609

Yep we use 5 smart chargers. For long term storage it was deemed best to pull the main starter battery right out and charge separately + leave the aux battery in and smart charge while left in car. Even short term - this is best. If the batteries were the same exactly - then it would have been ok to leave both connected in parallel - and charged together. Pos lead to one battery and negative lead to the other for a “balanced” charge.

What we do now is just remove the neg aux lead - and charge both in car - but separately. Cumbersome but is the best option.

 

[TrickyO]

Anyone found the location of the ESS battery on the RHD JL wrangler? All the posts and videos show how to remove it on the LHD vehicles. Pictures would be great and any removal instructions. Pretty sure mine has failed and is draining the main battery causing start issues, parking sensor dissables, "battery protection mode" messages and AUX switches dissabled as battery charging. Have had issues with ESS for some time (battery charging).

Location found under the main battery. Quite easy to get to with the main battery out. Replaced both. Main with an Optima H6 800 CCA and the ESS with a Decka. After taking the original batteries out, putting them on charge and then testing them the next day, it seems the main battery has failed. Wont hold a charge.

 

[Rhinebeck01]

Anyone found the location of the ESS battery on the RHD JL wrangler? All the posts and videos show how to remove it on the LHD vehicles. Pictures would be great and any removal instructions. Pretty sure mine has failed and is draining the main battery causing start issues, parking sensor dissables, "battery protection mode" messages and AUX switches dissabled as battery charging. Have had issues with ESS for some time (battery charging).

@TrickyO

Left hand or right hand drive, the Aux battery would be found under the power distribution center (PDC) you would think. Why wouldn't it be.

 

[TrickyO]

@TrickyO

Left hand or right hand drive, the Aux battery would be found under the power distribution center (PDC) you would think. Why wouldn't it

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