Ok, my friend was driving up to new jersey haulin horses, he's got an 06 dually, and smelt somehting funny. Dropped the horses and popped the hood and saw the the second battery was split and leaking. He took it to a shop, they said all was mechanicly ok and put a new battery in. He went back, reloaded for home and about an half hour later he smelt it again, pulled over and sure enoguh, the battery was split. What gives? what kind issue is he looking at???

Mike

 

Either the horse is kicking the edit out of it, or a badly overcharging alternator. It may not be PCM as should give a code. Look for occasional grounding of alt control wire or internal alt issue.

 

the shop said they tested it, and it was charging normal, plus, the other battery is still good, the main

 

changing one battery of a parallel pair isn't the best policy.

 

Just a wild shot but could there be anything around the battery that could be causing a spark off of the positive terminal? I blew up (split) a battery on my Subaru because of a baggie tie that stuck out far enough to contact the hood (when slammed shut) and the positive terminal.

 

Passenger side battery both times correct??

 

correct, both times

 

our dealer installed the solenoid to the jake on the battery box with the bolts pointing in i caught it when i was changing it to a bd it was already half way through the plastic the cable is big enough between the batteries that it has to be mechanical

 

Big cable won't mean a thing if the terminal at the right battery is corroded. The charging system is basically a big "loop" on these particular trucks. ECM monitors the batt voltage and determines the target charge and this circuit happens to originate at the left battery. Alternator output goes directly to the right battery. IF for some reason there is a poor or non existant connection between the batteries you can see where this is going to go. I've seen two cases like this and on both have split the loom on the B+ wire that connects both batteries. I remove the alt output wire from the B+ terminal at the right battery, cut off the eyelet and solder it in to the cross cable and seal it up with shink wrap and liquid electrical sealer. There it won't be suseptable to poor battery maintenance and there will not be a "weak link" in the charge system "loop". Basically change the "loop" to a "T".

 

i've heard of several 06 trucks doing this from the place where i buy parts hadn't heard of what caused or how to fix tho but i believe it was the 06 tho.

 

It's been several days with no activity, so figure may have resolved or pushed over a cliff. Look at electrical connections on main battery. Possible running off main battery and sensing voltage from main, but charging voltage going to right side. Low voltage on main and charging left like mad. Also look for failed cable.