So about 4 months ago my 2015 charger RT started shooting battery saver mode and the battery icon would randomly pop up. One night it died completely on me while driving going into limp mode. The next day we threw a new battery into it and it started up just fine but was overheating. Replaced the water pump, pulleys, and belt which fixed that issue right away. Battery light still came back on though. We went ahead and replaced the alternator thinking it would be good to go. Fast forward four months later and 3 batteries, 4 alternators and it’s still doing the same thing. Battery gets drained down and car ends up dying and going into limp mode. Only symptoms are battery icon popping up and my voltage on dash jumping around. Before it would go up to about 13v then drop back down to 11.7v. At this point it seems like it is just steadily decreasing. Brand new battery and alternator last night and from the drive home the new battery had gone from 12.2v to 11.7v. Sometimes it goes back up as if it wants to charge then goes back down to the consistent 11.5-11.8v. At this point have no idea and wanted to see if anyone out there has dealt with this headache!!

 

The alternator is not internally regulated, the PCM handles that. (which I though was a stupid idea.....) So, if voltage regulator has failed, or is causing issues, time for a new PCM.

Would be a good idea to make sure it isn't something silly, like a bad battery temp sensor..... If the PCM thinks the battery is too hot, it will stop charging.