Relocating and Upgrading Aux Battery?

[MrWaxman]

Can someone please explain to me why the Aux batteries in our Jeeps can't be relocated, for example to the rear tub, while also upgrading it to a bigger size.

My thought was, use the American Adventure Labs rear tub kit and put the aux battery in the rear for easy access and run the battery wires to the front. Terminate them together using a battery disconnect or similar method.

Any personal feedback would be appreciated. I've searched all over the forums and haven't found a similar post.

EDIT: Ecodiesel owner here, so no room in the engine bay to add a dual battery tray.

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[swampflyer]

Can someone please explain to me why the Aux batteries in our Jeeps can't be relocated, for example to the rear tub, while also upgrading it to a bigger size.

My thought was, use the American Adventure Labs rear tub kit and put the aux battery in the rear for easy access and run the battery wires to the front. Terminate them together using a battery disconnect or similar method.

Any personal feedback would be appreciated. I've searched all over the forums and haven't found a similar post.

You can!?
Go on the Genesisoffroad.com and look at the offerings.

 

[MrWaxman]

You can!?
Go on the Genesisoffroad.com and look at the offerings.

Im not talking about a dual battery system like Genesis.

I'm looking for something that would leave everything in stock form (not eliminate the Aux battery) but just relocate it and upgrade it to a larger size.

 

[AndySpill]

Following...

I'd make it the same size battery as the main. One of the major problems battery purists have with the JLs dual AGM battery ESS System is the dissimilar size batteries connected in parallel.

From what I understand its pretty safe to house an AGM battery in the cabin--perhaps not so a pure lead acid (non Absorbant Glass Mat) battery, but AGM yes.

Heck, devise a way to switch off which of the two batteries plays the role of "main," and "Aux" and you'll have IMHO devised how Stellantis should have best done the ESS dual battery system in the first place!

I'd be inclined to run the cables thru the hole fire wall on the passenger's side and thru the cabin like 8 pin tow harness install.

That said, would you consider buying the Genesis Offroad battery tray only and Group 25 dual batteries instead, keeping all your changes under the hood?

 

[MrWaxman]

Following...

I'd make it the same size battery as the main. One of the major problems battery purists have with the JLs dual AGM battery ESS System is the dissimilar size batteries connected in parallel.

From what I understand its pretty safe to house an AGM battery in the cabin--perhaps not so a pure lead acid (non Absorbant Glass Mat) battery, but this AGM variant.

Heck, devise a way to switch off which of the two batteries plays the role of "main," and "Aux" and you'll have IMHO devised how Stellantis should have best done the ESS dual battery system in the first place!

I'd be inclined to run the cables thru the hole fire wall on the passenger's side and thru the cabin like 8 pin tow harness install.

Exactly, same size batteries to eliminate the issues different size batteries connected in parallel and running those wires right through passenger fire wall straight to the battery area.

Then when you want to remove power from the jeep, you can turn the battery disconnect switch to the aux battery off and just remove battery terminals on the main. This seems much easier for diagnosing batteries while also having a power source in the rear.

 

[Punkn89]

Can someone please explain to me why the Aux batteries in our Jeeps can't be relocated, for example to the rear tub, while also upgrading it to a bigger size.

My thought was, use the American Adventure Labs rear tub kit and put the aux battery in the rear for easy access and run the battery wires to the front. Terminate them together using a battery disconnect or similar method.

Any personal feedback would be appreciated. I've searched all over the forums and haven't found a similar post.

Can you just get a dual battery tray and relocate the aux there with the main?

 

[MrWaxman]

Can you just get a dual battery tray and relocate the aux there with the main?

Sorry I should have said that I have an Ecodiesel. No room in the engine bay.

 

[AndySpill]

Exactly, same size batteries to eliminate the issues different size batteries connected in parallel and running those wires right through passenger fire wall straight to the battery area.

Then when you want to remove power from the jeep, you can turn the battery disconnect switch to the aux battery off and just remove battery terminals on the main. This seems much easier for diagnosing batteries while also having a power source in the rear.

TJ:

Turning the battery disconnect switch to off, with no other changes will cause your 2021 to likely not crank on the first attempt and on second and thereafter illuminate the ESS off light in the dash (EVIC) (the letter "A" with a near circle around it followed by an exclamation point icon).

Maybe you don't mind this light in the dash, which will go away at the next cold crank in which an energized ESS battery is detected.

Does the EcoDiesel come equipped from the factory with dual AGM batteries and ESS?

You can prevent this by pulling Fuse 42 or jumpering N1 to N2 in the PDC.

And if you don't turn your Aux battery switch to disconnect, remember that the Aux battery, under factory wiring, is connected to the main battery in parallel so appliances connected to your cargo area Aux, if not disconnected from your main, run down both batteries.

 

[THAW]

I'd make it the same size battery as the main. One of the major problems battery purists have with the JLs dual AGM battery ESS System is the dissimilar size batteries connected in parallel.

Exactly, same size batteries to eliminate the issues different size batteries connected in parallel...

What are the physics of dissimilar size batteries causing battery wear?

 

[MrWaxman]

TJ:

Turning the battery disconnect switch to off, with no other changes will cause your 2021 to likely not crank on the first attempt and on second and thereafter illuminate the ESS off light in the dash (EVIC) (the letter "A" with a near circle around it followed by an exclamation point icon).

Maybe you don't mind this light in the dash, which will go away at the next cold crank in which an energized ESS battery is detected.

You can prevent this by pulling Fuse 42 or jumpering N1 to N2 in the PDC.

And if you don't turn your Aux battery switch to disconnect, remember that the Aux battery, under factory wiring, is connected to the main battery in parallel so appliances connected to your cargo area Aux, if not disconnected from your main, run down both batteries.

I understand all this. I am not trying to run the jeep with the Aux battery disconnect.

I was simply saying that in the future if needing to replace batteries or diagnose battery voltages, it would be much eaiser to switch the disconnect to "OFF" (opening the circuit to from the main to the aux) as oppose to having to remove the wires from the aux battery off the main battery terminal.

I hope that makes sense.

 

[THAW]

I'd be inclined to run the cables thru the hole fire wall on the passenger's side and thru the cabin like 8 pin tow harness install.

...running those wires right through passenger fire wall straight to the battery area.

That's a very high amp (150) wire. Probably not the safest (or cheapest) thing to use such a long run and route it through the firewall.

 

[MrWaxman]

What are the physics of dissimilar size batteries causing battery wear?

From my understanding, the main battery is constantly trying to recharge the aux battery. Once the aux battery goes, the main battery will eventually go with it trying to keep the bad aux battery charged.

If I am incorrect, please chime in.

 

[MrWaxman]

That's a very high amp (150) wire. Probably not the safest (or cheapest) thing to use such a long run and route it through the firewall.

Interesting.. I didnt think about that. If this is true, then that is why it wont work.

 

[AndySpill]

Interesting.. I didnt think about that. If this is true, then that is why it wont work.

Why do I think that the instructions for the tow harness installation now route the wires below the cab (page 5 and 8)?

https://www.quadratec.com/sites/default/files/installation_instructions/K6864082AA.pdf

 

[THAW]

From my understanding, the main battery is constantly trying to recharge the aux battery. Once the aux battery goes, the main battery will eventually go with it trying to keep the bad aux battery charged.

If I am incorrect, please chime in.

I believe your above statement is correct. But, the same would happen if the 2 batteries are the same size, except we'd expect a longer life on the (now larger, same size) aux battery.

If you're already repositioning it to an easier to access location, it might be easier and cheaper to use a smaller battery, replacing it more frequently. Or you could use a bigger battery, replacing it less frequently.

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