Bad Battery or phantom menace?

[davidm767]

I'm sending my '24 2500 LTZ back to the dealer for what will likely be its 2nd replacement battery in the last 6 months. Last Sep/October I started to notice the battery was exceptionally weak. It progressed rapidly into a situation where the battery/batteries flat out would lose minimum voltage to start and basically cause chaos on my truck. I took it to the dealer in early November (after coming home from a big trip) and had the dealer look at it. They diagnosed the #2 battery as bad and replaced it under warranty. Now 6 months later (really 4 months, I'm just now getting to it) I'm having the issue again. Am I having a bad battery issue, or is there a parasitic drain that I'm/dealer not catching? To add, I installed a NOCO 2A direct mount trickle charger to the truck and plug it in about 1-2 days/overnights to keep the truck fresh. Thoughts?

Edited April 26, 2025 by davidm767

[Major Tom]

When one battery goes bad in a dual battery system, it will put more load on the good battery bring it down too.  Both batteries should have been replaced together.  I think you will find that the oldest battery is now the "bad" one and needs to be replaced.  Unless both batteries are replaced, in about four to six months, you will see the same problem again.