Disconnecting ESS AUX Battery to use as a backup

[DHP]

I searched for this but didn’t find anything specific to the JT. Apologies if I missed it and if it has already been answered, please link me to the answer

I'm following this thread at JL Wrangler Forum. https://www.jlwranglerforums.com/forum/threads/3-6l-ess-aux-battery-bypass.17293/
Basically the method I would use would boil down to disconnecting the AUX battery negative cable and using a jumper to still be able to use the ESS system off the primary battery. You could then potentially have the AUX battery as an emergency starter battery assuming you remembered to keep it topped off.

a summary another poster made of the options:

Here is a summary of all of the options:

Stock, dual battery - everything works as normal, ESS can be disabled, but the button has to be pressed every time the vehicle is started to disable. The downside is that if either battery goes bad, it will take down both batteries while the vehicle is off and be difficult to jump since you have 2 batteries with parasitic drain.

Stock, dual battery, Smart Start Stop, TazerJL, etc - Same as above but you don't have to press the button every time you start the vehicle.

Disconnect negative Aux cable - ESS is disabled and cannot be enabled. Upon every start of the vehicle an error stating to service the ESS system will popup on dash and go away after a few seconds, and a yellow light will illuminate and stay on. A bad AUX will not affect the main battery. Reconnecting the AUX will require a code reader to reset the ESS error.

Unplug PCR (ESS Relay), Disconnect AUX - AUX battery is disconnected, however ESS functions normally and works solely off the main battery, or needs to have the button pressed every time the vehicle is started. No error message or light

Jumper across fuse block terminals, Disconnect AUX - same as above, AUX battery is disconnected, however ESS functions normally and works solely off the main battery, or needs to have the button pressed every time the vehicle is started. No error message or light

Unplug PCR OR Jumper fuse block terminals, Disconnect AUX, add Smart Start Stop, TazerJL, etc - Same as above but you don't have to press the button every time you start the vehicle. No error message or light




Has anyone done this on their JT and have you run into any issues? Anything I should make sure to avoid?

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[Mac]

Seems risky to jumper things in the fuse panel and disconnect the second battery, if it shorts something out or messes up the computer it could be very costly. Don’t really see the benefit, just carry a decent jumper pack.

 

[DHP]

Thanks for the reply. Just looking to see if anyone has done this on a JT.

 

[LaterGator]

I replaced the oem setup with a dual battery (genesis mount) and used a solid-state hellroaring battery isolator to isolate the batteries. The 2nd battery is a true backup. No loads connected to it unless I need it to start the jeep and it is disconnected from the primary battery if the ignition is off. When ignition is on and alternator voltage is above 13.2 volts the backup battery is charging. Flip a switch to connect the backup battery and start the jeep. I had to use it once after letting the JT sit for 4 weeks waiting on parts and time to work on it.


ESS still works but I use the Tazer JL mini to disable it. No error messages or lights.

 

[DHP]

I replaced the oem setup with a dual battery (genesis mount) and used a solid-state hellroaring battery isolator to isolate the batteries. The 2nd battery is a true backup. No loads connected to it unless I need it to start the jeep and it is disconnected from the primary battery if the ignition is off. Flip a switch to connect the backup battery and start the jeep. I had to use it once after letting the JT sit for 4 weeks waiting on parts and time to work on it.

ESS still works but I use the Tazer JL mini to disable it. No error messages or lights.

Alright this is a response I was hoping for. I saw discussion around the Hellroaring isolator. Did you just buy the Genesis tray and then this isolator? Did you do anything similar to the link I posted from JL Forum as far as creating a jumper for N1 and N2 to keep ESS from still working or at least not throwing error codes? I have the Tazer as well and would likely just keep it disabled but it would be nice to have the option. Does it automatically charge when the engine is running? Any other info would be appreciated!

 

[Mr._Bill]

For what you are looking at, I think the Genesis Dual Battery kit would be a good choice. It includes an Isolator that keeps the batteries charged, and disconnects the secondary battery from the primary if it starts discharging.

 

[DHP]

For what you are looking at, I think the Genesis Dual Battery kit would be a good choice. It includes an Isolator that keeps the batteries charged, and disconnects the secondary battery from the primary if it starts discharging.

problem with it seems to be that you get the error messages on the dash while using it. Unless I’m misunderstanding their product page and a couple of forum threads I’ve read. That kit was what made me know I wanted something like this

 

[jebiruph]

I searched for this but didn’t find anything specific to the JT. Apologies if I missed it and if it has already been answered, please link me to the answer

I'm following this thread at JL Wrangler Forum. https://www.jlwranglerforums.com/forum/threads/3-6l-ess-aux-battery-bypass.17293/
Basically the method I would use would boil down to disconnecting the AUX battery negative cable and using a jumper to still be able to use the ESS system off the primary battery. You could then potentially have the AUX battery as an emergency starter battery assuming you remembered to keep it topped off.

a summary another poster made of the options:

Here is a summary of all of the options:

Stock, dual battery - everything works as normal, ESS can be disabled, but the button has to be pressed every time the vehicle is started to disable. The downside is that if either battery goes bad, it will take down both batteries while the vehicle is off and be difficult to jump since you have 2 batteries with parasitic drain.

Stock, dual battery, Smart Start Stop, TazerJL, etc - Same as above but you don't have to press the button every time you start the vehicle.

Disconnect negative Aux cable - ESS is disabled and cannot be enabled. Upon every start of the vehicle an error stating to service the ESS system will popup on dash and go away after a few seconds, and a yellow light will illuminate and stay on. A bad AUX will not affect the main battery. Reconnecting the AUX will require a code reader to reset the ESS error.

Unplug PCR (ESS Relay), Disconnect AUX - AUX battery is disconnected, however ESS functions normally and works solely off the main battery, or needs to have the button pressed every time the vehicle is started. No error message or light

Jumper across fuse block terminals, Disconnect AUX - same as above, AUX battery is disconnected, however ESS functions normally and works solely off the main battery, or needs to have the button pressed every time the vehicle is started. No error message or light

Unplug PCR OR Jumper fuse block terminals, Disconnect AUX, add Smart Start Stop, TazerJL, etc - Same as above but you don't have to press the button every time you start the vehicle. No error message or light




Has anyone done this on their JT and have you run into any issues? Anything I should make sure to avoid?

The thread you referenced is my thread. The jumper allows the system to pass the cold start aux battery test when the aux battery is disconnected. I'm very confident that the JT ESS system is identical to the JL, but I haven't gone through my JT to test everything. This has been discussed for years (2.5) in the Wrangler forum, this thread is a good source of information. https://www.jlwranglerforums.com/forum/threads/3-6l-ess-dual-battery-consolidated-information.25377/

Here's the newest development https://www.jlwranglerforums.com/forum/threads/ess-dual-battery-management.60034/

 

[DHP]

The thread you referenced is my thread. The jumper allows the system to pass the cold start aux battery test when the aux battery is disconnected. I'm very confident that the JT ESS system is identical to the JL, but I haven't gone through my JT to test everything. This has been discussed for years (2.5) in the Wrangler forum, this thread is a good source of information. https://www.jlwranglerforums.com/forum/threads/3-6l-ess-dual-battery-consolidated-information.25377/

Here's the newest development https://www.jlwranglerforums.com/forum/threads/ess-dual-battery-management.60034/

Glad you responded! Wasn’t sure if you stayed active on this forum or just over on the JL side. Your threads are a wealth of knowledge. Thanks for taking the time. That second link is exactly what I’m looking for. I’ll study it and I might have some more questions

 

[LaterGator]

I just got the genesis tray and purchased isolator from hellroaring. N1 and N2 are both connected to the primary positive terminal. The IBS is connected to the primary negative terminal.

 

[LaterGator]

The Genesis and Hellroaring isolators operate differently. The Hellroaring isolator is solid-state and has no parasitic current draw when the ignition is off. It also completely isolates the batteries below 13.2V unless the combiner switch is closed. The combiner switch has 3 settings: combine both batteries to use the backup, both batteries isolated and backup charging (normal mode), and batteries completely isolated.

The Smart Alternator charging system is really annoying. On long trips, I have seen the battery voltage drop as low as 12.6 volts while driving. Below 13.2V, the backup stops charging and is isolated from the main battery.

 

[DHP]

The Genesis and Hellroaring isolators operate differently. The Hellroaring isolator is solid-state and has no parasitic current draw when the ignition is off. It also completely isolates the batteries below 13.2V unless the combiner switch is closed. The combiner switch has 3 settings: combine both batteries to use the backup, both batteries isolated and backup charging (normal mode), and batteries completely isolated.

The Smart Alternator charging system is really annoying. On long trips, I have seen the battery voltage drop as low as 12.6 volts while driving. Below 13.2V, the backup stops charging and is isolated from the main battery.

Is the benefit of the Hellroaring just that you have more options and can totally separate the backup battery or is the parasitic draw a big concern? Does it still have the limit of the 6 ESS events like the genesis setup?

 

[LaterGator]

any mechanical solenoid will eventually fail. I have a 17 yo Hellroaring unit on my TJ. The 6 or 7 ess events is still a limit, but I never turn ESS on. And no parasitic draw and the cutout at 13.2V is a plus as the backup stays fully charged.

 

[DHP]

any mechanical solenoid will eventually fail. I have a 17 yo Hellroaring unit on my TJ. The 6 or 7 ess events is still a limit, but I never turn ESS on. And no parasitic draw and the cutout at 13.2V is a plus as the backup stays fully charged.

Pardon my ignorance on the solenoids, if the HR is a mechanical one, what is the solenoid on the Genesis system?

 

[LaterGator]

Hellroaring unit is solid-state. no moving parts. The genesis system uses a heavy-duty 100% duty factor mechanical solenoid.

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