Can you mix group size in a bank?

[agallant80]

I have two banks each bank has a size 24 in it. Can I add a size 29 to one of the banks so it will look like below?

Bank1: 1X size 24
Bank2: 1X size 24 and 1X size 29


Thanks!

 

[JoLin]

Re: Can you mix group size in a bank?

Your starter and accessories don't care- they need a certain number of amps @ 12V to operate. The size group relates only to the size of the outer case, though a larger physical battery tends to supply more cranking and reserve capacity (amps) than a small one.

As long as the construction of both batteries is the same (flooded, AGM, gel) it doesn't matter. The reason you want same-construction batteries in the same bank is for the sake of your (hopefully) 'smart' battery charger, whose charging 'brain' is programmed to match the profile of the type of battery it's charging.

My .02

 

[agallant80]

Re: Can you mix group size in a bank?

That raises another question. Does the alternator know what type of battery you have?

 

[bruceb58]

Re: Can you mix group size in a bank?

I am guessing the bank 2 is your house bank and you want to add capacity. I personally don't like paralleling batteries to increase capacity, especially if they are not identical batteries and the exact same age.

The alternator doesn't know anything about the batteries.

 

[Howard Sterndrive]

Re: Can you mix group size in a bank?

imo, any paralleled batteries should be identical. I don't even mix brands. I have had gassing issues when one wants to charge easier than the other.