Hillbilly Aux Battery Relocation?

[AndySpill]

I would appreciate hearing from forum members about why moving the Auxiliary battery from its factory position behind the front passenger's tire, to the location in the picture would be a bad idea.

Sure. "Why keep the Aux battery in the first place, or why not get a Genesis Offroad relocation kit (because its pricey)" are valid questions but off topic.

I'd definitely create something to secure the battery in this place, but would appreciate comments like "it gets too hot there," or "the loss of ampacity given the length of cabling" might make this a poor choice.

I'd definitely extend the factory cables with no less thick cabling and I already have run said cabling behind the engine and up against the firewall for years for other appliance applications without any problems.

I guess I'm getting to old to want to replace this battery thru top or side access, and too stingy to pay Stellantis to do it for me.

TIA.

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[Reinen]

First, those cables will be significantly longer. At that length voltage drop starts to become a concern. Main and Aux are connected 99.99% of the time and the IBS manages them. The longer cable length will cause the IBS to see the voltage of the Aux battery slightly lower than it actually is. Will that confuse IBS and cause a problem? IDK, but it might in theory. At the very least I would go with 1 GA lower (larger) cables than OEM to possibly mitigate the voltage drop concern.

The primary physical concern is heat. Specifically heat from a hot engine freshly turned off to park. With a Rubicon, you can open the existing hood vents and you'll likely be fine. The hot air coming off the engine can go up & out. But a Sahara doesn't have those. Hot air is going to pool up under the hood until it finds its way out the radiator grille, heat soaking the battery.

On a 2.0T I'd say that spot is a definite no-go. Too close to the very hot turbo. But this doesn't look like a 2.0T so I assume this is a 3.6. I don't have a 3.6 so I can't speak to how hot things get over there. Maybe put a temperature probe in that spot, get the engine nice and hot, then park the Jeep. See if the temperature probe goes out of the battery's upper working temperature spec (which is typically around 140F).

 

[AndySpill]

First, those cables will be significantly longer. At that length voltage drop starts to become a concern. Main and Aux are connected 99.99% of the time and the IBS manages them. The longer cable length will cause the IBS to see the voltage of the Aux battery slightly lower than it actually is. Will that confuse IBS and cause a problem? IDK, but it might in theory. At the very least I would go with 1 GA lower (larger) cables than OEM to possibly mitigate the voltage drop concern.

The primary physical concern is heat. Specifically heat from a hot engine freshly turned off to park. With a Rubicon, you can open the existing hood vents and you'll likely be fine. The hot air coming off the engine can go up & out. But a Sahara doesn't have those. Hot air is going to pool up under the hood until it finds its way out the radiator grille, heat soaking the battery.

On a 2.0T I'd say that spot is a definite no-go. Too close to the very hot turbo. But this doesn't look like a 2.0T so I assume this is a 3.6. I don't have a 3.6 so I can't speak to how hot things get over there. Maybe put a temperature probe in that spot, get the engine nice and hot, then park the Jeep. See if the temperature probe goes out of the battery's upper working temperature spec (which is typically around 140F).

Thanks. It is in fact a 3.6L.

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