3.6L ESS Aux Battery Bypass

moodywizard

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Any new upgraded aftermarket options for the aux battery?
No, but in hindsight I might have went with a jackery portable battery vs genesis setup. Different strokes for different folks.
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There are many of us that are operating with a disabled ESS (on purpose) and have no need for the aux battery. Is it safe to say that it (the small aux battery) can simply be removed or stay in place as dead weight without any long term consequences? For someone like myself that will NEVER use the ESS system, is the small aux battery even necessary? Under normal circumstances I would just pull the small aux battery, but it isn't that easy to get to without ripping open a pathway...again I am just going off of what I have read on these forums and have not yet had a need to go there. At some point it will be inevitable.

I think there is so much information floating around that those of us that are not great with electrical components remain a little confused.

If I continue to use my Jeep with the ESS disabled and eventually when my main battery gives up its starting capability, can I just replace the main battery and disregard any condition that the aux battery is in, OR is there a better way to approach the situation?

I have received some great information here, but it is still not completely clear what the best option is. I know others are equally confused.

Thanks in advance for any additional insight.
Bypass it with a jumper *and* a battery switch. Keep it healthy with a tender. I put my main on a tender once a week, and my bypassed ESS on a tender once every month or two. It could be a handy emergency jump source, someday, so I have no intention of removing it. I use a Tazer (but also own a Smart Stop Start) to keep ESS disabled.

All of this is in Jerry’s bypass thread:https://www.jlwranglerforums.com/forum/threads/3-6l-ess-aux-battery-bypass.17293/
 

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There are many of us that are operating with a disabled ESS (on purpose) and have no need for the aux battery. Is it safe to say that it (the small aux battery) can simply be removed or stay in place as dead weight without any long term consequences? For someone like myself that will NEVER use the ESS system, is the small aux battery even necessary? Under normal circumstances I would just pull the small aux battery, but it isn't that easy to get to without ripping open a pathway...again I am just going off of what I have read on these forums and have not yet had a need to go there. At some point it will be inevitable.

I think there is so much information floating around that those of us that are not great with electrical components remain a little confused.

If I continue to use my Jeep with the ESS disabled and eventually when my main battery gives up its starting capability, can I just replace the main battery and disregard any condition that the aux battery is in, OR is there a better way to approach the situation?

I have received some great information here, but it is still not completely clear what the best option is. I know others are equally confused.

Thanks in advance for any additional insight.
David: I thought Will @WranglerMan did a good job with this and trust his posts.

Maybe I can add some color commentary here.

First, my discussion pertains to the 3.6L engine JL. Will was smart to discuss the specifics of whether the battery is still connected if present.

  • The removal of an ESS battery from the vehicle, without properly redirecting the cables that connect to its terminals, will render a 2018 3.6L JL unable to crank unless it has been flashed at the dealer with TSB 18-092-19. All 3.6L JLs seek to test the voltage of the ESS battery upon cold cranking the vehicle. If this battery is dead, or the cables that lead to it don't form a circuit (i.e. the battery is seen by the vehicle as dead) a 2018 3.6L won't even attempt a crank. If running with this TSB or a 2019 model year or later, the vehicle will automatically attempt the crank from the main battery. If successful ESS will be disabled until the next cold crank, if any, where the cables that lead to the ESS battery detect adequate current. This can come from addressing a malfunctioning ESS battery or redirecting its cables to an energized source (such as the main battery) such that the vehicle is tricked into thinking the ESS battery is working properly.
  • While I can see no reason to think that continued operation of the vehicle with solely the main battery is bad, I am of the opinion that ESS should not be used in this situation, as doing so may increase the risks of a motorist getting stranded, particularly in bad and dangerous situations. My reason for saying this lies with an understanding of how ESS events deliberately tax only the ESS/Aux battery so the bulk of the cranking power can come from the spared (during ESS events) main battery. We don't want to be running ESS off the main battery, which will happen if we redirect the ESS battery's cables to the main battery, with the 3.6L thinking (wrongly) that it is merely taxing the ESS battery during such ESS events (when it's actually taxing the main battery,) running ESS too long, and possibly unable to crank having run down the main battery. Yes, a fair number of vehicle ESS systems run one battery, but the 3.6L isn't designed to.
  • As Will discusses, anytime the ESS battery is connected in parallel (which is 99% of the time in the factory 3.6L) it can be an energy source or sink. A defective ESS battery (or vice versa) can seek to charge itself in the voltage potential difference of a superiorly charged working main battery, draining it in the process.
  • With ESS disabled you can run your 3.6L as you described, using the same approach you would with any 1 battery vehicle.




 

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No issue running my genesis setup for 1.5 years with the IBS sensor removed for full time 14V+ charging. I dont trust anything or any word that comes from someone working at a dealer. Sorry for those that are offended.
When you say you removed the IBS did you physically remove it or just unplug it, I used JSCAN for a short period of time to disable the IBS and saw 14+ all the time but figured there was no sense in cooking my batteries if not needed so I just enabled it back and do weekly charges with a NOCO 10 then monthly I do a reconditioned charge using a Odyssey 20
 

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David: I thought Will @WranglerMan did a good job with this and trust his posts.

Maybe I can add some color commentary here.

First, my discussion pertains to the 3.6L engine JL. Will was smart to discuss the specifics of whether the battery is still connected if present.

  • The removal of an ESS battery from the vehicle, without properly redirecting the cables that connect to its terminals, will render a 2018 3.6L JL unable to crank unless it has been flashed at the dealer with TSB 18-092-19. All 3.6L JLs seek to test the voltage of the ESS battery upon cold cranking the vehicle. If this battery is dead, or the cables that lead to it don't form a circuit (i.e. the battery is seen by the vehicle as dead) a 2018 3.6L won't even attempt a crank. If running with this TSB or a 2019 model year or later, the vehicle will automatically attempt the crank from the main battery. If successful ESS will be disabled until the next cold crank, if any, where the cables that lead to the ESS battery detect adequate current. This can come from addressing a malfunctioning ESS battery or redirecting its cables to an energized source (such as the main battery) such that the vehicle is tricked into thinking the ESS battery is working properly.
  • While I can see no reason to think that continued operation of the vehicle with solely the main battery is bad, I am of the opinion that ESS should not be used in this situation, as doing so may increase the risks of a motorist getting stranded, particularly in bad and dangerous situations. My reason for saying this lies with an understanding of how ESS events deliberately tax only the ESS/Aux battery so the bulk of the cranking power can come from the spared (during ESS events) main battery. We don't want to be running ESS off the main battery, which will happen if we redirect the ESS battery's cables to the main battery, with the 3.6L thinking (wrongly) that it is merely taxing the ESS battery during such ESS events (when it's actually taxing the main battery,) running ESS too long, and possibly unable to crank having run down the main battery. Yes, a fair number of vehicle ESS systems run one battery, but the 3.6L isn't designed to.
  • As Will discusses, anytime the ESS battery is connected in parallel (which is 99% of the time in the factory 3.6L) it can be an energy source or sink. A defective ESS battery (or vice versa) can seek to charge itself in the voltage potential difference of a superiorly charged working main battery, draining it in the process.
  • With ESS disabled you can run your 3.6L as you described, using the same approach you would with any 1 battery vehicle.
Im of the thought that if you use ESS with the ESS battery disabled that after (6) cycles of ESS that the JL will disable ESS and the logic built into the start sequence looms for two separate voltages ( main and ESS ) and once you hit the 6th cycle you will get a EVIC warning and it won’t be available until the ignition is cycled and then the cycle starts over.

The reason I say this is I run a Genesis dual system and Mike, Shane Fro Genesis and I had talks about this ( Mike at Genesis is super knowledgable on the JL ESS system ) anyway after i went to my Genesis system I had to test this and sure enough after (6) cycles ESS disables itself and after a restart it resets and this system moves the ESS positive off the ESS battery to the main crank battery and the ESS negative is disconnected on the main crank and that’s basically the same and removing the ESS battery as the Genesis is basically one big battery when the relay is energized .
 

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David: I thought Will @WranglerMan did a good job with this and trust his posts.

Maybe I can add some color commentary here.

First, my discussion pertains to the 3.6L engine JL. Will was smart to discuss the specifics of whether the battery is still connected if present.

  • The removal of an ESS battery from the vehicle, without properly redirecting the cables that connect to its terminals, will render a 2018 3.6L JL unable to crank unless it has been flashed at the dealer with TSB 18-092-19. All 3.6L JLs seek to test the voltage of the ESS battery upon cold cranking the vehicle. If this battery is dead, or the cables that lead to it don't form a circuit (i.e. the battery is seen by the vehicle as dead) a 2018 3.6L won't even attempt a crank. If running with this TSB or a 2019 model year or later, the vehicle will automatically attempt the crank from the main battery. If successful ESS will be disabled until the next cold crank, if any, where the cables that lead to the ESS battery detect adequate current. This can come from addressing a malfunctioning ESS battery or redirecting its cables to an energized source (such as the main battery) such that the vehicle is tricked into thinking the ESS battery is working properly.
  • While I can see no reason to think that continued operation of the vehicle with solely the main battery is bad, I am of the opinion that ESS should not be used in this situation, as doing so may increase the risks of a motorist getting stranded, particularly in bad and dangerous situations. My reason for saying this lies with an understanding of how ESS events deliberately tax only the ESS/Aux battery so the bulk of the cranking power can come from the spared (during ESS events) main battery. We don't want to be running ESS off the main battery, which will happen if we redirect the ESS battery's cables to the main battery, with the 3.6L thinking (wrongly) that it is merely taxing the ESS battery during such ESS events (when it's actually taxing the main battery,) running ESS too long, and possibly unable to crank having run down the main battery. Yes, a fair number of vehicle ESS systems run one battery, but the 3.6L isn't designed to.
  • As Will discusses, anytime the ESS battery is connected in parallel (which is 99% of the time in the factory 3.6L) it can be an energy source or sink. A defective ESS battery (or vice versa) can seek to charge itself in the voltage potential difference of a superiorly charged working main battery, draining it in the process.
  • With ESS disabled you can run your 3.6L as you described, using the same approach you would with any 1 battery vehicle.



After reading through this entire topic; this is my summation of how to modify a 2018 3.6l to run without an aux battery and not have to have it reflashed at the dealer as detailed above. Anybody, please correct me or add any additional steps not called out below

Disconnect the power control relay connection from T3 fuse block terminal, wrap it with electrical tape or completely remove the relay from the vehicle.

Disconnect the positive lead connection at the aux battery, reconnect this lead to the main battery.

Disconnect the negative aux battery connection, wrap it with electrical tape

Additional question; can the the aux battery main positive cable be easily connected to the main battery? Please explain exactly what has to be done to accomplish this reconnection.

I also disabled ESS through the hood open switch. I will also be removing the aux battery from the vehicle.

Thank you.
 

moodywizard

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When you say you removed the IBS did you physically remove it or just unplug it, I used JSCAN for a short period of time to disable the IBS and saw 14+ all the time but figured there was no sense in cooking my batteries if not needed so I just enabled it back and do weekly charges with a NOCO 10 then monthly I do a reconditioned charge using a Odyssey 20
Just unplugged, believe it has a few ground connections on it and didn’t have the effort to physically remove and redistribute the wiring and posts etc. With my daily driving and the fridge running 24x7 I need it 14v all the time to charge 2nd battery. No problem since running odyssey batteries
 

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What’s the downside to having it flashed?
 

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Just unplugged, believe it has a few ground connections on it and didn’t have the effort to physically remove and redistribute the wiring and posts etc. With my daily driving and the fridge running 24x7 I need it 14v all the time to charge 2nd battery. No problem since running odyssey batteries
Like you I’m running the dual Genesis system but no fridge just a winch and a few other things connected to the second battery, I primarily wanted the Genesis system to make getting to batteries easier plus the huge boost from running two full size batteries that are the same size and identical maker, I’m running Full River 750’s and my JL seems to love the boost as electrically it seems so much happier.

I don’t have the beefier 240 alternator as I don’t have the tow pkg but I do weekly conditioning of my batteries to keep them healthy but, I doubt in the long run that there will be any ill effects of pushing 14+ volts to the batteries all the time
 

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What’s the downside to having it flashed?
Zero. That TSB fixes a lot of annoying issues, too, like super loud A/C fan.
 

moodywizard

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Like you I’m running the dual Genesis system but no fridge just a winch and a few other things connected to the second battery, I primarily wanted the Genesis system to make getting to batteries easier plus the huge boost from running two full size batteries that are the same size and identical maker, I’m running Full River 750’s and my JL seems to love the boost as electrically it seems so much happier.

I don’t have the beefier 240 alternator as I don’t have the tow pkg but I do weekly conditioning of my batteries to keep them healthy but, I doubt in the long run that there will be any ill effects of pushing 14+ volts to the batteries all the time
I don’t have the high output alt either, all accessories are running off 2nd battery. Winch, BD lights, fridge, arb twin, rockhard steps, etc. I definitely notice when they close in parallel, especially when running the compressor lol
 

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Im of the thought that if you use ESS with the ESS battery disabled that after (6) cycles of ESS that the JL will disable ESS and the logic built into the start sequence looms for two separate voltages ( main and ESS ) and once you hit the 6th cycle you will get a EVIC warning and it won’t be available until the ignition is cycled and then the cycle starts over.

The reason I say this is I run a Genesis dual system and Mike, Shane Fro Genesis and I had talks about this ( Mike at Genesis is super knowledgable on the JL ESS system ) anyway after i went to my Genesis system I had to test this and sure enough after (6) cycles ESS disables itself and after a restart it resets and this system moves the ESS positive off the ESS battery to the main crank battery and the ESS negative is disconnected on the main crank and that’s basically the same and removing the ESS battery as the Genesis is basically one big battery when the relay is energized .
Will,

I too am really thinking about investing in the Genesis Dual Battery system, if for nothing other than just replacing the AUX with a similar sized MAIN. The Genesis solution looks to be so much superior than anything FCA has provided.

It looks like FCA (Stellantis) has eventually solved the ESS disaster with the non-optional eTorque system with a 48v battery solution, but I digress.

Regardless, what I'd like to do is simply puzzle out how to rid my 2019 Sport of the AUX without losing the ESS functionality altogether. I absolutely despise that this ESS functionality was shoved down our throats due to CAFE and Carbon Tax bureaucracy, (but that's an entirely separate topic).

However, and I admit I'm the oddball here, I really don't mind not wasting fuel when idling. In fact, it has become rather fun playing with the dynamics of letting it engage (or not) given all the various stopping conditions I regularly find myself in.

Some people like playing with the clutch, well it turns out I like playing with either the ESS pushbutton or the hardness / lightness of the brake pedal nearly every stop. So while most people see this as a pure unadulterated nuisance, I'm having a lot of fun with it. Really.

I'm loving everything about my JL experience both on and off-road but I unceremoniously despise this AUX battery design. It Sucks with a capitol 'S' for ALL the reasons stated in this thread. I'm hoping to pull the trigger soon, before needing to replace this god-awful AUX battery contraption. Also hoping not to get stranded in the meantime.

However I have to do my homework and puzzle out how to rewire the Genesis system to play nicely with the IBS and PCR so that the ESS isn't automatically disabled every six cycles. Jerry's (@Jebiruph), your's and others most excellent posts regarding this subject lead me to believe that the IBS must be able to sense two (2) independent battery voltages, rather than an identical single instantaneous voltage measured twice from one battery in order to keep ESS enabled for more than the six cycle limit. The engine controller can't be easily fooled into a false sense of happiness simply by jumpering the two together as in the overall solution everybody here is clambering to install.

So I know it's possible to simply replace the AUX battery with the Genesis second one but without having the Genesis system to puzzle this out, I'd like to know what specifically needs to be done before pulling the trigger. Since you already have this system, even though you've disabled ESS outright, do you have any thoughts or idea's on this oddball configuration.

I suppose I can contact Genesis (perhaps even Mr. Shane) to work this all out. Maybe I could then also select which is the Main and which is the AUX as the batteries inevitably will wear differently over time.

Either way I would really appreciate your thoughts.

Thanks a bunch for all your previous posts.
Jay
 

Gee-pah

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Im of the thought that if you use ESS with the ESS battery disabled that after (6) cycles of ESS that the JL will disable ESS and the logic built into the start sequence looms for two separate voltages ( main and ESS ) and once you hit the 6th cycle you will get a EVIC warning and it won’t be available until the ignition is cycled and then the cycle starts over.

The reason I say this is I run a Genesis dual system and Mike, Shane Fro Genesis and I had talks about this ( Mike at Genesis is super knowledgable on the JL ESS system ) anyway after i went to my Genesis system I had to test this and sure enough after (6) cycles ESS disables itself and after a restart it resets and this system moves the ESS positive off the ESS battery to the main crank battery and the ESS negative is disconnected on the main crank and that’s basically the same and removing the ESS battery as the Genesis is basically one big battery when the relay is energized .
Correct Will. In a 3.6L, if the vehicle detects identical voltages between (what it thinks) is the ESS/Aux battery and the main battery, in 6 consecutive tests, ESS is disabled because the vehicle assumes that for such identical voltages to manifest 6 times in a row, the only way that could happen is for some wiring malfunction to exist (in this case a user created wiring rerouting) that parallel connects both batteries, even at an instant during pre-crank when the vehicle (attempts) to separate them, and that they are registering one composite voltage together in parallel.

So, yes, checks already exist within the rig to not allow habitual running of ESS with one battery should the terminals normally leading to the ESS/Aux battery be rerouted to the main battery.

Unfortunately, with my luck, I'll be stranded in an ESS stop on the 5th crank in which I've rerouted my ESS battery terminals, eliminated this battery, and failed to expressly turn ESS off.
 

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... what I'd like to do is simply puzzle out how to rid my 2019 Sport of the AUX without losing the ESS functionality altogether.
Hey Jay--long time no talk. (There is nobody I'd rather form a dissenting opinion against than Jay because he argues so smartly and diplomatically, but I digress as we're on the same page here.)

It's funny you mention this. I think you refer to the fact that after 6 cold cranks in a 3.6L, should identical voltages between detected in the ESS/Aux battery and the main battery, (or what the rig thinks are these two batteries given owner rewiring) ESS is disabled-the rig fearing some wiring problems lies within the system.

And yet, permanently parallel connecting the two batteries, or simply rerouting the ESS/Aux battery cables to the main battery (which can be found in Jerry's hack or the otherwise extremely well designed Genesis product) will ultimately kill ESS after 6 consecutive cold cranks.

Beyond my scope, I was wondering if some "doodad" could be placed between the wires that normally lead to or from the ESS battery, and those that then permanently parallel connect to the main battery, to create a temporarily different voltage on one of the batteries, as seen by the 3.6L upon startup, to trick the vehicle into NOT throwing this diagnostic condition after 6 cold cranks with identical voltages between the main and ESS battery.
 
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