3.6L ESS Battery Basics

Jebiruph

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I have observed that there may be a need for some basic ESS based electrical theory. For those that struggle to understand how electricity works, some basic electrical concepts can be better understood by using basic plumbing concepts. Substituting water for electricity, pipes for wire and water pressure for electrical voltage may make it easier to understand some of how the ESS batteries work.

To that end, I have redrawn my ESS Battery Diagram as a plumbing diagram to help illustrate how the system works. I represent the batteries as tanks to store water under pressure, the alternator is a pressure pump and the starter is a turbine. I use various intensities of blue to represent the levels of pressure in the system.
pipes-base.PNG

This is the normal start diagram (not from an auto stop) with fully charged batteries. Both batteries are providing pressure to the system, so both batteries are providing power to the starter. Even if ESS is disabled, the batteries are still both connected to the system and both provide power to the starter.
pipes-starting.PNG

This is the engine running diagram with the alternator providing power to the system. As long as the pressure from the alternator is greater than the pressure in the batteries, the batteries will pressurize to their limit and will not discharge.
pipes-charging.PNG

This diagram shows a bad Aux battery that won't fully charge. The engine is off, so no alternator pressure. The higher pressure of the fully charged main battery will be discharging into the lower pressure of the bad Aux battery until the pressure equalizes, which over time reuslts in 2 dead batteries.
pipes-bad-aux.PNG

Here's 2 dead batteries on the verge of being jump started with a booster pack. Virtually no pressure in the system at all.
pipes-discharged.PNG

Here's trying to start with the booster connected to the discharged system. The pressure from the booster is distributed throughout the system and there is not enough pressure available at the starter to start. As the pressure accumulates in the batteries, more pressure then becomes available for the starter. If the booster is too small, it will not be able to pressurize the whole system to the point where it will be able to power the starter.
pipes-boosted.PNG

Let me know if you have any questions or comments.


(updated 04/13/2019)
Additional 3.6L ESS system information is available here.
3.6L ESS Dual Battery Consolidated Information
https://www.jlwranglerforums.com/forum/threads/3-6l-ess-dual-battery-consolidated-information.2





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OldGuyNewJeep

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THANK YOU!
 

WreakingHavoc

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I have observed that there may be a need for some basic ESS based electrical theory. For those that struggle to understand how electricity works, some basic electrical concepts can be better understood by using basic plumbing concepts. Substituting water for electricity, pipes for wire and water pressure for electrical voltage may make it easier to understand some of how the ESS batteries work.

To that end, I have redrawn my ESS Battery Diagram as a plumbing diagram to help illustrate how the system works. I represent the batteries as tanks to store water under pressure, the alternator is a pressure pump and the starter is a turbine. I use various intensities of blue to represent the levels of pressure in the system.
pipes-base.PNG

This is the normal start diagram (not from an auto stop) with fully charged batteries. Both batteries are providing pressure to the system, so both batteries are providing power to the starter. Even if ESS is disabled, the batteries are still both connected to the system and both provide power to the starter.
pipes-starting.PNG

This is the engine running diagram with the alternator providing power to the system. As long as the pressure from the alternator is greater than the pressure in the batteries, the batteries will pressurize to their limit and will not discharge.
pipes-charging.PNG

This diagram shows a bad Aux battery that won't fully charge. The engine is off, so no alternator pressure. The higher pressure of the fully charged main battery will be discharging into the lower pressure of the bad Aux battery until the pressure equalizes, which over time reuslts in 2 dead batteries.
pipes-bad-aux.PNG

Here's 2 dead batteries on the verge of being jump started with a booster pack. Virtually no pressure in the system at all.
pipes-discharged.PNG

Here's trying to start with the booster connected to the discharged system. The pressure from the booster is distributed throughout the system and there is not enough pressure available at the starter to start. As the pressure accumulates in the batteries, more pressure then becomes available for the starter. If the booster is too small, it will not be able to pressurize the whole system to the point where it will be able to power the starter.
pipes-boosted.PNG

Let me know if you have any questions or comments.
Very impressive! Maybe the best effort into a forum post I've seen, well done!
 

WranglerMan

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@Jebiruph you have been a great help to me in so many ways so thanks again for making it easier to understand this whole duel battery system
 
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Jebiruph

Jebiruph

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@Jebiruph you have been a great help to me in so many ways so thanks again for making it easier to understand this whole duel battery system
Thanks for your comments, glad it helps.
 

OldGuyNewJeep

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@Jebiruph, one question - any idea what size booster could get the job done? And how long it’d need to be connected to pressurize the system? i.e. would AAA be able to jump a JL with their commercial grade booster if they let it be for a few minutes?
 

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So does this mean when one or two batteries went out, we cannot just go to Autozone or AAP to swap the batteries but have to go through dealer?
 

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Does anyone have specs on the aux. battery? CCA, reserve capacity, etc? I'm betting that upgrading to a higher quality battery to replace the aux. battery would result in a more reliable system.
 
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Jebiruph

Jebiruph

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Does anyone have specs on the aux. battery? CCA, reserve capacity, etc? I'm betting that upgrading to a higher quality battery to replace the aux. battery would result in a more reliable system.
This number was posted by some one BBAUA200AD
 
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Jebiruph

Jebiruph

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So does this mean when one or two batteries went out, we cannot just go to Autozone or AAP to swap the batteries but have to go through dealer?
My plan for the remainder of my warranty is to bypass the Aux battery if needed until I can get to the dealer and only buy a main battery if I can't get it to the dealer.
 
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Jebiruph

Jebiruph

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@Jebiruph, one question - any idea what size booster could get the job done? And how long it’d need to be connected to pressurize the system? i.e. would AAA be able to jump a JL with their commercial grade booster if they let it be for a few minutes?
@Rhinebeck01 had a dead battery incident where the tow truck's booster pack wasn't quite enough, but following with the trucks dual battery system got it done. I don't know what it would take to boost a totally depleted system, but it may not take much for a partially depleted system. My plan would be to bypass the aux battery and jump start the main battery only, reconnecting the aux battery after it starts. Myself, I will keep an eye out for good deal on a quality booster pack.
 

OldGuyNewJeep

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@Rhinebeck01 had a dead battery incident where the tow truck's booster pack wasn't quite enough, but following with the trucks dual battery system got it done. I don't know what it would take to boost a totally depleted system, but it may not take much for a partially depleted system. My plan would be to bypass the aux battery and jump start the main battery only, reconnecting the aux battery after it starts. Myself, I will keep an eye out for good deal on a quality booster pack.
Bypass as in simply disconnect it’s negative lead?
 

WranglerMan

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My plan for the remainder of my warranty is to bypass the Aux battery if needed until I can get to the dealer and only buy a main battery if I can't get it to the dealer.
If you choose to bypass it how would it remain charged, and by bypassing do you mean the jumper connected to N1 and N2 then the ESS negative disconnected off the main correct ?
 

WranglerMan

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Bypass as in simply disconnect it’s negative lead?
I believe bypassing the ESS battery requires a jumper like this between N1 and N2, your choice on how to connect but wingnuts are the easiest

B96812EC-7B20-431E-953D-D837EDF2AA42.jpeg
 

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