When it’s running, you’re seeing what the alternator is putting out. If you shut it off and put it on run, I’d expect to see it lower. Keep in mind it’s not clear which battery is low, if it’s not both after 3 years. You can isolate them and test separately, but after 3 years I just replaced both. No issues since. I’ve had the replacements since early 2023 I think. Optima yellow top for the main, die hard aux 14 for the aux. both from advanced auto.
If the Jeep is 3 years old, the batteries won’t be covered. And the dealer is likely to jack up your Jeep.
Sounds good thanks.
That's the alternator output, not the battery voltage. And if it STAYS there, then it's sensing the batteries have an issue. It should actually vary from 15.0 when cold out to 12.7 when things are totally charged, and somewhere between 13.0 to about 14 as you drive with fully charged batteries.
15 I’ve never seen, but otherwise yep. Exactly. 14.4 is I think the max I’ve seen on the JT.
It’s three years old. I wouldn’t overthink it. This is your early warning that your batteries are about to fail. Just replace them both and everything will be grand.
Don't use the run mode to check voltage - that's checking the batteries with a load on them.
