‘21 3500 CCLB 4x4 HEMI battery randomly dying - help please

[copcarguy]

Hello all,

The battery in my truck occasionally goes stone cold dead overnight. I replaced the original battery this past June at 15K miles as it went randomly dead twice. We were going on an extended RV adventure so I figured it was 4 years old and I didn’t want to worry about it on the road. Got a new EverStart Platinum AGM battery from Walmart as their warranty was 1 year longer than anyone else and the price was good. Also since Walmarts are everywhere if we were on the road, warranty issues would be easy to take care of. So last month, I go out and the truck is dead again. Like so dead, no dome lights, nothing. I charged it and it was fine for a couple weeks. Then randomly dead again. I swapped it out under warranty and got a new (now third) battery. Truck was fine for a couple weeks, now this week stone cold dead again. I charge it all day, and it’s been fine for a couple days. So now I know it’s probably an issue with my truck. My charger has a “test alternator” function which it is saying the truck passes. I have unplugged everything, set the lights to off, turned off the light delay, etc.

Any ideas?

 

[Blackpowder]

Sounds like your charging system is not adequately charging the battery as you drive it, or your truck is drawing enough current when off to drain the battery (or both). Check your terminations to make sure they are clean and snug. Seems unlikely you would get 2 new bad batteries back to back.

Did you notice what voltage your battery/alternator are at while you were driving it? (via the dash display). I also replaced the batteries in my 2021 3500 diesel this summer with Walmart AGM's. When the battery is fully charged, the alt puts out 13.8V - 13.9V. When the battery state of charge drops, it ramps the voltage up to 14.3V - 14.4V max.