Dear Dave,
I wonder about the best way to configure six 6-volt batteries. I have the traditional method of connecting two 6-volt batteries in series and then connecting them parallel to two additional pairs. But I wonder about the option of connecting the first three batteries in parallel and a second set in series. Does either setup provide a better, stronger, or longer-lasting power supply, or do both configurations yield identical results? —Colin
Diagram provided by Colin:
Dear Colin,
Your RV needs 12-volt power to run items such as lights, vents, water pump, and appliances that run on LP such as the refrigerator and furnace. When you connect two 6-volt batteries in series it is positive to negative, which creates a 12-volt bank but does not double the amp hours.
According to your diagram, the amp hours is 200, so when you connect the first two in series you get 12 volts and 200 amps. When you do this for the second and third pairs, you have three 12-volt banks with 200 amp hours each. Then, when you connect those pairs parallel, it is positive to positive and negative to negative, which keeps the voltage at 12 volts but now doubles and triples the amp hours. In your traditional method, you have 12 volts and 600 amp hours.
Optional method
If you connect the left side three 6-volt batteries in series, which is positive to positive and negative to negative, you create a 6-volt bank with 600 amp hours. Same with the right side three 6-volt batteries. When you connect the two, three-battery banks, you get 12 volts but still 600 amp hours.
So you are getting the same results in voltage and amp hours but adding three more cables and much more maintenance, in my opinion. Therefore, I do not see any advantage, but I do not see anything that would not make this work.
Let’s put it out there to see if anyone has used this optional setup. I wonder whether one method produces optimal power for a longer period or do both methods produce the same results?
You might also enjoy this from Dave
6-volt or 12-volt batteries for RVs—Which is better?
Dear Dave,
I keep reading about using two 6-volt batteries in series for RVs. Why? It seems like it would be simpler to have one 12-volt or two 12-volt batteries in parallel. Sorry, still a newbie trying to figure all this stuff out. —Richard, 2023 Geo Pro 19FDS
Dave Solberg is a leading expert in the RV industry and the author of the “RV Handbook.”
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Yes, I did slip! I meant to say the two 6-volt batteries that are now connected in series to create a 12-volt bank should be connected parallel which would be positive to positive, negative to negative.
I said “series” which was not correct
I was under the impression that positive to positive is parallel, not series. Did I miss something?
You’re correct. Dave slipped up.