house batteries

Replaced original 12 volt house batteries last Spring with two 6 volt Trojan T-105s hooked up in series. Worked pretty well. This Summer we are going on an extended trip, mostly boondocking and for safety's sake, I think that I will add 2 more T-105s; the two pairs in parallel with each other. Each battery weighs 62 pounds and it's a little extra weight.
A friend's suggestion is to get a Trojan 12 volt scs225 and run that parallel to the two 6 volt in series. It would take 60 pounds off the weight. I have a class A with no real weight problems but I do like to stay as lean as possible.
How do you all think?


Senior Member
house batteries

Putting a 'small' 12v battery in parallel with 2 'big' 6v series batteries could give you problems with little gain in capacity. For best effect, you want the batteries in parallel to be as identical as possible. Any discrepancy between the parallel legs could result in the batteries 'fighting' each other.

For best capacity, I'd go with 2 more T-105s, which will give you at least double your current capability. I might investigate mixing one new one and one old one in each series leg to keep them as identical as possible.

A lower weight solution would be to trade in the old T-105s on 2 12 volt batteries in parallel. Probably will actually lose some capabillity tho; the 105s are hard to beat...

A possible compromise would be to have 2 battery banks, one with the T105s and 1 with the single 12 volt, and a switch to use one or the other. Making sure both got charged would be tricky tho...