How Does My Dual Battery Set-up Work?

[sahls01gmc]

I have an 01 GMC 2500 with the dual battery set-up. Originally when I got the truck, there was a connector by the passenger side battery that was unhooked, and that battery was not charged. After replacing both batteries over the years, I have also hooked up that connector, which seems to keep the battery charged.

 

My question is: What is my dual battery set-up used for? If I have the connector unhooked, or the battery taken out on the passenger side, my truck works just fine. What is the benefit for having the second battery? Is it for use with a camper trailer when hooked up?

 

 

Appreciate your time

 

 

James

[old-chevy-dude]

from my research, one battery is the main and always maintains a charge for starting the truck, the second runs all the accessories when the key is off, (off road lighting, snow plow, campers, etc), when the key is on both batteries work together with the priority for charging going to the main battery.

 

if the second is dead or disconnected the first takes over the accessories. The system is supposed to always maintain 1 battery for starting the truck, so if the second dies from say leaving the lights on with key off, the main battery is isolated so you can still start the vehicle.

[sahls01gmc]

Ah, ok. That makes sense. Would I run into any issues if I only have 1 battery hooked up? Is the charging system designed to charge 2 batteries all the time, or is the "2nd" battery just for accessories, and gets charged either way?

 

 

Appreciate the info!

 

 

James

[[email protected]]

You'll be just fine with only one battery, dual batteries was just an option mostly for the snow plow prep. And it's standard for the d-max, if you have a d-max I suggest you leave two batteries.

[sahls01gmc]

Nope, just the 6.0L, but I will definitely leave both batteries as I am gearing up to have a plow next winter.

 

Appreciate it all!

 

 

James

[old-chevy-dude]

the main battery will get priority on charging, as long as it's full the second battery will then charge.. it doesn't charge them at the same time, but alternates between which one needs it, but always putting priority on the primary starter battery.