Kinda late, but here’s the latest update from our road trip from Dec. it took about an 1 hour and 20 minutes at 65-70mph no stops and the “still charging” never went off, this is with the A button
not pressed. Compass sat for 8 hours, about 45 minutes into our return trip the notice went go off and Start/Stop indicated “Ready”. The DIC display always shows 14.4v since purchase date 5.2018. About 30 minutes later into downtown traffic lights, it shut off like normal. After unpacking I took a few readings, the main battery and starter battery read identical at 12.5v. a tad low considering the 1+ drive, from past experience I would expect around 12.85v. The next morning identical readings again at 12.5v. I’ve been checking it in the AM this week and its been dropping consistently 12.46v, 12.22v, 12.15v and holding at 12.1v. on start up it drops to about 10v, which is normal. I think anything under 9v may indicate an issue. During the Christmas Holidays the Compass sat unused for a week. I checked the voltage and to my surprise it had not dropped past 12.1v. started right up and everything seems OK, but ESS still not working “Battery Charging”. One thing I have noticed while its running is the charging voltage has dropped to 14v -14.2v, kinda odd. I did find some information on the JLWranglerForums having the same issues. My concern now is how much “strain” is on the electrical system including the alternator from a constant marginal battery. My next step is to do a simple battery module reset and see what happens …
"The ESS system can be quite picky and even many dealers don't really seem to know what to do with them. In my experience one thing that
must always be done before troubleshooting or replacing any parts is to perform the service manual-prescribed reset procedure, which involves removing the negative battery terminal for a few minutes and reconnecting, then driving the vehicle through at least five complete drive cycles (i.e. full warm up and normal road operation, then complete cool down and rest for at least 8 hours, and repeat.) For most people a week's worth of normal daily operation should do it. The BMS needs to observe a repeatable happy state of affairs with the battery and charging system before ESS will be permitted, and the reset procedure should provide it.
If the only error your are seeing is a constant '
Battery Charging' and nothing else is wrong with the system then in many cases the above will resolve the glitch, sometimes even better than a dozen trips to a dealer who throws unnecessary parts at the problem."
https://www.youtube.com/watch?v=rp9wUQT0MRs Disconnecting the Battery
https://www.jlwranglerforums.com/forum/threads/ess-not-ready-battery-charging-question.41103/page-2
https://www.jlwranglerforums.com/forum/threads/3-6l-ess-ibs-information.22585/
https://www.jlwranglerforums.com/forum/search/289036638/
https://jeepcherokeeclub.com/4-2014-jeep-cherokee-general-discussion/238378-ess-electric-start-stop.html