Dual batteries

-
Matts440

Matts440

Well-Known Member
Joined
Apr 11, 2014
Messages
3,163
Reaction score
1,872
Location
Nampa, Idaho
What would you all recommend doing for a dual battery set up? Mostly street but with drag race it, just run both all the time of get a switch to go between one or the other or both?
 
Matts440 said:
What would you all recommend doing for a dual battery set up? Mostly street but with drag race it, just run both all the time of get a switch to go between one or the other or both?
Click to expand...

I run 2 gel batteries tied together both for cranking power and ballast........
 
Okay so you just hooked your positive to positive and then grounded each battery?
 
I hooked my positive to positive and ground to ground then one ground goes to my common grounding block where all other grounds go as well.
 
You really should devise a method of separating them when parked. Even batteries that are "matched" IE bought at same time, and same brand/ model, etc, don't last as long, generally, as a single. Even if all you do is to unscrew the ground on one, and "pull" the disconnect on the car.
 
So do you think the dual battery controller from painless would be a good option? it allows you to use one or the other or both can switch between the three choices
 
A link to the thing would be nice...........

the marine / fire truck / etc industry has used Off / A / B / Both battery switches for a very long time.

You could do this cheaper and easier, just put the "NHRA approved" disconnect in the common positive line. This of course shuts off everything, but would leave the two connected in parallel.

A second disconnect in ONE of the remaining battery positive would then split the two apart. Those switches are (relatively) cheap.

Lots of ways to "skin this cat."
 
My 2005 petebuilt has 4 batterys hooked up ground to ground pos. To pos and class 8 trucks have been doing this for at least50 years you don't need a 3way switch my 2 cents
 
jockeyshift said:
My 2005 petebuilt has 4 batterys hooked up ground to ground pos. To pos and class 8 trucks have been doing this for at least50 years you don't need a 3way switch my 2 cents
Click to expand...
I was going to say the same thing.My Mack has 4 batteries and sometimes I only run 2 or 3 and never gives a problem. I have other equipment that some are hooked pos to ground on each to make 24 volts so I don't see the need to separate when parked
 
The reason to separate the bats is that if thet are not perfectly ballanced (the exact same voltage) one will try and charge the other and you will end up with two dead batterys...
 
I ran my last drag car with the batteries in parallel. Never had one drain to the other or any problems like that... And every other racer I know runs them that way too... It works just fine.

Other things to worry about in life.. This is not one of them...
 
not all bats discharge at the same rate nor do they take charge at the same rate.

In a race car, yeah you may never have a problem. In something that you dont want to fail, its a requirement...
 
Why would you want to run 2 batteries. I have been racing for 30 yrs and have only ran a single battery. And have never had a problem.
 
only reason to run dual batterys is if you have a car with no alternator like a drag car,plus on a drag car its good ballast,your alternator is working over time to charge 2 batterys for a street car,might be ok if you have a electric water pump and fans,elitric fuel pump,i run 2 truck batterys in my drag car,batterys should be mounted parrell,so plates don't hit each other during launch
 
Well the car has, 6 fans, two fuel pumps, a electric motor for the intercooler to push water and the normal gauges x9, and a decent stereo, plus fuel injection and 8 coils
 
I hate to use the "F" word here, by the Ford 'Camper Special" truck I had years ago had two batteries under the hood. One solely for the truck, the other solely for the camper. The setup from the factory kept both charged while driving, but they were separated otherwise so the camper battery never drained the truck battery.
You might do the same. One battery solely to start the car, the other solely for the accessories.
 
I think I would try this first

[ame="https://www.youtube.com/watch?v=GPJao1xLe7w"]12V BoostPack. Replaces auto battery. Works great! - YouTube[/ame]
 
You must log in or register to reply here.
-

Back
Top