dual batteries

[camper]

Hi, I have a 1984 chevy truck, 3/4 ton, I think it used to be a phone truck, has a utility bed on it, anyway it has a dual battery set-up. How does this set-up work? I need a new battery, in the past, I always just changed them both out, is this neccesary? can I get by on just One? I have asked mechanics in the past, but no one could ever tell me the answer. Thanks.

[Irish_Alley]

Think about this if you change just one battery in a remote it will die faster than if you changed both the dead battery will suck the life out of the other when you go to use it. Now car batteries are similar but at the same time different, what i would do is get both tested take them out and get them tested. If just one test ok i would just replace that one, if you have the money replace both. Because let’s say the old battery is only sitting at 11 volts and has a problem reviving itself back to 11 volts once you try to start it. The new battery is sitting at 12 but once you hook the batteries together it will be at 11 and have to help the weaker battery every time thus weakening the good battery to almost the same as the weaker battery

[topp]

Think about this if you change just one battery in a remote it will die faster than if you changed both the dead battery will suck the life out of the other when you go to use it. Now car batteries are similar but at the same time different, what i would do is get both tested take them out and get them tested. If just one test ok i would just replace that one, if you have the money replace both. Because let’s say the old battery is only sitting at 11 volts and has a problem reviving itself back to 11 volts once you try to start it. The new battery is sitting at 12 but once you hook the batteries together it will be at 11 and have to help the weaker battery every time thus weakening the good battery to almost the same as the weaker battery

With an Isolator this does not happen, and I believe there is a factory setup that prevents this, keeping both batteries isolated from each other.

I run a dual battery setup with an Isolator. one for starting ONLY and the other for accessories. I only need to replace the one that goes bad, but both batteries must be the same (CCA, etc..) for the system to work right...

[Irish_Alley]

never used one lol good point top.

[malibu795]

Batts are setup parrell. There is no remote bat. Simple law of electricity. Unless there is a switch to isolate it there is. No remote.
Ideally u replace all at once. But one @ a time ie one dead and on good isn't goin to hurt anything.. just make sure both have same cca rating. If one is drainin and the other not. Check ur wires between the two bats. There is continuity issues there by not allowing both to drain @ same rate

[jaredts]

Irish didn't say one battery was a remote battery.  He said if you change one battery in a remote the bad battery will drain the good one.  What engine do you have?  If its a diesel you need both.  If its a bbc you might consider keeping both.  If you use winches or off road lights or high amp accessories keep both.  Otherwise consider dropping the second battery and just using one.

[Irish_Alley]

when i said remote i ment like a tv remote lol

[ehjorten]

Reading that post was pretty painful

[choptop]

Too be honest, if you dont need the dual battery setup. get rid of one and save some money. My extended crew had the dual batteries and ones going bye-bye. Its only a stock 454 so one will work fine. My deisel truck, however, will keep the dual batteries. In short, if you replace one, Id recommend replacing both. I work on industrial engines doing the electronic control systems, and I have had many customers cheap out by buying one battery and it bite them in the but 90 percent of the time.
 The way mine are setup, the battery on the left has a positive cable that runs across the rad support and ties in with the positive on the battery on  the right. Simply remover the crossover cable. On the negative side, Ive seen two ways, either it will have the cable that runs across to the negative on the right (passenger side) battery or it will just run to the block. Just remove this cable as well. Most of the important grounds are on the right side battery anyway. dont think there are any little grounds hooked up on the left battery. Hope this helps.

[camper]

Thanks for the input, I will probably just change them both out, I know it has always started good in the winter.