Does a constant 14V mean something’s wrong?

[dccurtis]

@dccurtis

Actually, constant / always running at 14+ is not the normal... you should not typically see this if you have a dual battery JL/JT with both a healthy Aux and Main battery.

To see 14-14.1 or so and then see a drop to say 13.2 or 13.4, 13.8 and then back up to 14.2 or so is typical.

When you start up the JL say in the morning you will see 14 or so but after driving awhile you should see the 13.2, 13.8 to 14.0+ , up and down, ongoing dance.

IF you do a bunch of short hops to the barbershop then to grocery store, to gas station, etc., where the JL sees little driving time and a bunch of ignition on and off's, yes, you will see 14.0 ish until you drive enough so that the 12v is replenished and the JL gets back to the 13.2, 13.8 to 14.0+, up and down, ongoing dance.

IF the JL sits for a couple of days or more unused, when you do finally run the JL, you will see 14.0+ for a period of time to the 12v replenishes.

Note: After you change out an Aux battery.... after the changeout... say in 3 or days and you see the JL running constant 14.0ish, and maybe you see an EVIC notice, it is indicative that when you fooled with the JL's battery(2) you inadvertently blew a fuse in the High Amp Fuse Array..

Also.... after you changout batter(s) expect weird readouts until IBS has did it's relearn that takes a few days of your using/driving your JL.

.

Thanks for the info here! I'll keep an eye on it. I agree that running 14ish all the time doesn't seem to be consistent with what I've seen others report... I was thinking of replacing the IBS next if the AUX battery replacement didn't fix ESS. Now that ESS seems to be OK again, maybe I'll keep an eye on the voltage instead...

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[dccurtis]

If you’re seeing a constant 14v or over, you main battery is probably weak. It will pull voltage from the new aux battery and you will soon be in the same boat.

Pull the cables from the main and charge it. If it takes a full charge, you should see you alternator voltage output numbers drop. If the numbers don't drop, consider replacing that battery with a quality 94R H7, which is the largest battery that will fit in the tray.

awesome point. I'll do this!

 

[Rhinebeck01]

I remember reading somewhere that the 2.0 only has one battery so it doesn't have this issue.

With the 2.0 you will see the same dance as I mentioned in my last post. IF you see constant 14.0+ and you do not see the dance I mentioned, that means the Main battery on the 2.0 JL is not up to snuff 12v wise.

 

[Rhinebeck01]

Thanks for the info here! I'll keep an eye on it. I agree that running 14ish all the time doesn't seem to be consistent with what I've seen others report... I was thinking of replacing the IBS next if the AUX battery replacement didn't fix ESS. Now that ESS seems to be OK again, maybe I'll keep an eye on the voltage instead...

Give your JL's IBS some time to learn. Don't just replace ..
https://www.jlwranglerforums.com/forum/threads/ibs-clear-reset.67955/

Remember what I said about blowing the High Amp Fuse array fuse... as it happening is fairly common.
Read this terrific thread: https://www.jlwranglerforums.com/fo...-cable-caution-and-ess-n3-fuse-warning.66247/

 

[The Last Cowboy]

With the 2.0 you will see the same dance as I mentioned in my last post. IF you see constant 14.0+ and you do not see the dance I mentioned, that means the Main battery on the 2.0 JL is not up to snuff 12v wise.

Agreed. I think we were typing at the same time.

 

[Rhinebeck01]

@dccurtis

I was just reading from the beginning of this thread....... --> IF you did not change out your Mainthe other day when you changed out your Aux, you undoubtedly made a mistake.

More then likely... I would wager on it --> the Main you installed say a couple of yrs. ago, has aged out / is iffy and should be replaced or you are at high high risk that the Main will negatively impact your newly installed, Aux battery.

Costs money to properly load test the Main, so just replace it versus throwing $ at it, testing it.

With that said don't be $ foolish. Go spend the $200 or so and replace the Main battery, ASAP. Do right away.

Read here: https://www.jlwranglerforums.com/forum/threads/??-main-battery-replacement-talk-jl-jt-?.100534/

 

[CarbonSteel]

To @Rhinebeck01's valid point about the N3 fuse blowing...my experience is that it is not some obvious "in your face" thing that happens. I replaced my aux and shorted the posts on the battery by accident (and did not realize it at the time) and put everything back together. There were no warnings or EVIC messages immediately after the battery replacement, so I thought all was well.

Everything was fine for about 2 weeks, then the "Service ESS" message appeared randomly in the EVIC, but would go away. At that point, I was not sure what it meant. A couple of days after that, the "Service ESS" appeared and remained. Less than 10 miles after that happened, the "Check Engine" light came on and shortly after, it started running rough to the point that I was not sure that I would make it back home.

I connected my OBD scanner and had a couple of codes including one that stated "Left Engine Bank Lean" and was a permanent code meaning that I could not clear it with the scanner--the condition that set it had to clear before the code would.

Taking @Rhinebeck01's advice, I moved the wire from N3 to N4 on the high amp fuse array and within a few miles, the Lean code had cleared. Over time, the voltage came down from a constant 14.4v to the upper 13.x and lower 14.x range. My daily commute is about 14 miles and unless I take a longer drive on the weekends, I rarely see the voltage drop below 13.6v or so.

My point is that you should always remove and separate the negative and positive cables on the main battery to prevent accidentally blowing the N3 fuse which ranges from $60 to $80 depending on where you buy it.

 

[The Last Cowboy]

And that fuse array isn’t something you just pick up at any auto parts store. It’s also impossible to tell you blew one by looking at it. Bad design.

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