2 months ago I had to buy 2 new batteries from AAP for my 2007 5.9 because it wouldnt start on the old batteries. In the process I cleaned and neutralized the terminals and leads. However, a month in a half later I hear a boom while I was driving my truck and the result was one of the caps had blown off my secondary battery along with a generous amount of acid. They told me it was the alternator and voltage regulator so I had the alternator replaced. But my secondary kept venting gas and acid so I disconnected the ground form the secondary and have been running on the primary for 3 weeks until I just got a new secondary battery today. After 5 minutes of running same thing with the cap and acid in my engine bay. Does anyone have any thoughts on this. Truck runs fine on the primary but overcharges on the seondary?

 

I'm on my phone now but try searching here. I know I've seen something similar posted before. Over charging just one battery.

 

I've seen this on here also a few months back. I can't remember it might be something to do with the cable that runs over to the second battery or bad ground?

 

Here is the thread I was thinking of. See post #3 for some info on how these work

https://www.dieseltruckresource.com/...light=charging

 

Thank you very much for the help. I will look into it and keep yall updated on progress.

 

The root cause of the concern is a poor connection between the two batteries. remove and clean the battery cable ends and the battery terminals of the cable that connect to both positive side battery terminals. Pull the battery bolts and clean with battery cleaner and brush.