Why did my battery die?

[Rhinebeck01]

It would be a fine system if the battery wasn't a junk battery in a crap location. NEVER should they have put a battery Under the Fuse box that you have a high chance of damaging a connection when pulling the system apart or putting it back together.. I run my jeep on a tender for both batteries, Doesnt matter if i drive it or not. its on the charger so i dont have the issues of the trash battery going out once a year. if you want piece of mind and the ability to change the battery If it goes dead then the dual full battery system is the way to go plan and simple. My Pick up thats 40+ years old has had the same battery for 8 years now... its gets drive once every two weeks...... still doing better then my JLU batteries

@Maverick

Not sure if you know this, but pulling the PDC is not the recommended or suggested way to get to the Aux battery.. Actually, the worst way to do it.

Sure would be nice if the Aux was right in the engine compartment ..... but it can be easily accessed by peeling back the fender flare liner which is how FCA tells the Techs to do it.. An even easier way that takes less then say 15 min. is to just pull the fender flare.. Neither approach is chancey.. risk of damage, etc... other then a few rivets or a fender liner clip(s).

Anyway, just wanted to clarify that it is not suggested / recommended to go pull the PDC to do the job.

IF a guy just has a clue lets say, the stock dual battery system is not that difficult to understand / to deal/live with... and of course..... you can always, replace the OEM battery(s) with aftermarket offerings that are beefier/better.

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[WranglerMan]

I agree the genesis is an extremely useful system in cases such as that, it’s like you always have a space full size battery to jump start from, but I still cant justify the cost for what it is.

Another reason I went to a full size dual battery system is I did not want things like aux lights, winch and air compressor coming of my main battery, it’s not like I use any of those a lot but I just think a crank battery needs to do one thing and that is crank your vehicle.

I do know that everything that runs thru the PDC comes off the main and the JL has a normal parasitic draw in stock form but when we start adding programmers, dash cams and other aux equipment that puts even more demand on the main battery so with the extra full size in reserve that gives me piece of mind, it’s not a perfect system but better than the crappy stock system.

There are lots of other options that are a lot cheaper and we as Jeep owners have to decide what is best for our needs.

 

[OldGuyNewJeep]

I have a 2020 JLUR Eco Diesel with 16k miles. I bought it used in November and have only put approx. 2k miles on it. Since I purchased it I have installed the MC Gamechanger 3.5 lift and new tires, as well as the Tazer Mini and new Rock Slide Engineering steps. It was working great when I went out of town 10 days ago and when I returned home yesterday the battery was dead. I tried charging it but I got a message saying the battery was bad. I called AAA and they came and jump started it so I could get it over to the dealer who is now saying I need a new battery.

Does anyone have any ideas why the battery would be bad all of a sudden after not starting the Jeep for 10+ days?

You’re getting a lot of good replies, but let me give you the executive summary:

• Stock batteries are not very good quality.
• Infrequent, short trips are not sufficient to keep batteries charged. Remember, your alternator is charging two batteries in parallel with this system
• There is parasitic draw even when kept stock

Your best bet is to use a battery tender to keep your batteries healthy. With COVID keeping me home most of the time, I put my batteries on a tender once a week. Probably overkill, but better safe than sorry.

I have also disconnected my ESS negative with a battery switch and use a Tazer to prevent ESS from engaging. Not a required mod, but it eliminates the possibility of a bad cell in either battery from drawing down the other.

The Noco Genius 5 tender is great for the big AGM main battery. I charge the smaller AUX with a Deltran Battery Tender Plus. (The Noco puts out a bit too much juice for that little AUX.) Note that when I was stock (before upgrading to a beefier NorthStar main battery and bypassing my AUX) I used the Deltran to charge both in parallel, and it seemed to work well for that task. At 2.5 years my AUX failed and was replaced under warranty. Shortly thereafter my main started showing signs that it was about to fail so I upgraded it.

CTek is another popular tender option.

If you want to replace your main with a better option like I did, see here.

Note: I am unfamiliar with the diesel and am assuming it has the same battery setup as the 3.6.

 

[dwade1]

Thanks for all of the comments. I still have no idea why the battery would have gone bad after only 12 days of non use. That said, I took it to the dealer and they replaced the ESS battery. They said that the main battery is still okay.

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