Battery dead every 5-6 months

[Jebiruph]

I'm also curious if anyone having this issue has had the PCM recall taken care of before the issue came up, and if the recall took care of it.

On a side note, I had the tender hooked to the main battery. The service rep told me that the little tractor battery is what starts the engine, not the main battery (wouldn't they put the big draw on the big battery?!). He also said that connecting the tender to the main battery won't touch the little aux battery. Seems weird that a little battery would be the one that starts the engine, and it seems weird that last fall when it died I hooked the charger to the main battery and it started up.

The service rep is wrong, the main battery is the starting battery, that's why the starter is connected to it. And connecting a charger to the main battery also charges the aux battery unless there's another problem like a blown N3 fuse.

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[zakaron]

I’ve owned mine for about 1.5yrs and not had an issue with either battery. I have a work vehicle, so there are times where it may sit for days without starting. And it stays outside year round.
@Jebiruph is correct about the batteries, the purpose of the aux battery is to run the accessories during an ess event, protecting the main battery from run down so it can start the vehicle. When out of ess, both batteries are connected to receive charging, so hooking up an external charger will do both batteries.
I have read on other posts that the uconnect online enabled Jeeps can run down the battery faster because it is constantly connected to some cloud server. I have the 7” screen, so there is no online service on mine, but could be a consideration if your battery keeps running down.

 

[OldGuyNewJeep]

For what it's worth, I have an '18 JLU with the 3.6 v6.

TSB 18-092-19 Needed so Jeep will crank on second try if AUX is dead. Don't say ESS because that TSB doesn't mention it. Say the A/C fan is too loud.

If not worried about head unit agree to sign a waiver, or just disconnect it before you bring it in.

What tender do you have? You need at least 10a one for main AGM battery. Noco-10 is very popular.

Consider implementing Jerry’s AUX bypass + ESS disabled (Smart Stop Start or Tazer). Refer to the pinned posts in the Battery Talk forum.

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