Battery issue

[jsq789]

07 2500 with the 5.9

When on 1 battery it turns over slow but then runs great.
When on both batteries the alternator doesn't kick in and the passenger side battery cooks and spills acid all over.

Took it to the dealership and they drove it and couldn't get the problem to happen.

Until I figure the problem out, can I run on 1 battery?

 

[USMC1188]

I would put 2 new batteries in it, and start there. Are the batteries factory originals?

 

[DannyMK2]

I would put 2 new batteries in it, and start there. Are the batteries factory originals?

x2. have your alt tested while your at it.

 

[USMC1188]

x2. have your alt tested while your at it.

That is a good idea... make sure to unplug them and test them each individually or else they will give you false readings off of each other.

 

[Revery]

I realize your post is 10 years old, but di you figure out what was wrong I have a 2007 2500 with a Cummins 5.9 and it just started doing the same thing. The batteries are only 1 month old and probably less that 100 miles of usage. Took the overflowing battery back to vendor and they gave me a new one and it does the same thing so know it's not the battery. Thanks for any viewer reply.

 

[jr27236]

I realize your post is 10 years old, but di you figure out what was wrong I have a 2007 2500 with a Cummins 5.9 and it just started doing the same thing. The batteries are only 1 month old and probably less that 100 miles of usage. Took the overflowing battery back to vendor and they gave me a new one and it does the same thing so know it's not the battery. Thanks for any viewer reply.

OP sounds like the voltage regulator in the alternator is no good and allowing the alternator to overcharge. Dont know how they have these wired but the one over flowing is probably the first one as they are wired parallel. Simply put a voltage meter on and check the charging voltage while the engine is running

 

[Revery]

Thanks for the reply, I believe you are right the battery that is overcharging is connected to the alternator. However I am not sure if the alternator is wired through the ECM or a separate voltage control. So not sure if that could be the problem. Problem seems to occur after the engines warms up a bit. I'll check this weekend when I have a few minutes.

 

[jr27236]

The voltage regulator on new alternators is in the alternator itself and your forced to buy a new one or have yours rebuilt which today I myself cant find anyone who does that anymore.

 

[Dennis Shellito]

What you are experiencing is an anomaly caused by the system volt reading (what your truck thinks the voltage is) from the drivers side battery, and when it senses that a charge is needed it charges the passenger side battery first. If the cable syncing both batteries to each other is faulty it causes what you have going on. Yes, you can run with one battery and should until you replace the positive cable running between the dual batteries.