2 6-volt or 2 12-volt batteries

^^^ Yes

If I understand the prior memos, when you hook-up 2 batteries in series, in this case the 6 volt golf cart batteries, you would have approximatly 235 ah. When you hook-up 2 batteries in parrallel, in this case hooking up two 12 volt, you double the ah, thus getting 210, if the batteries are 105 ah each. Is that correct?

If I had a vented compartment that would hold four flooded lead acid type batteries they would be 6v industrial true deep cycle ones. If one cell in one battery failed I would disconnect it and its partner battery from the bank and still have the 12v needed for the RV electronics (fridge, water pump, furnace control, lights). I could then wait until it was convenient to get the bad battery replaced or might decide to replace two or all four batteries.

With only two batteries and use out on the open road the better choice is two matched 12v batteries.

A common mistake made is to compare a FLAT battery performance and cost and longevity with an AGM battery. For RV use the AGM is not likely to last as long and it will cost twice as much up front.

FLAT batteries will handle partial discharge and partial recharge cycles better than AGM type batteries and this contributes to their longer life when used in an RV.

Less than 6v batteries in auto group sizes and larger are made to keep the weight of the battery manageable by the average human without need for a forklift or a hoist. Insustrial batteries come in voltage outputs as low as 2v and are commonly used for data centers, phone company switch installations, and cell towers.

Eurocamper wrote:

I guess that somewhere you can buy 12 volt deep cycle batteries with more than 100-105 Ah capacity, but I couldn't find any. On the other hand, there were plenty of 6 volt golf cart batteries with 225-235 Ahs to choose from. I figured I would go for the 235 Ah over the 210 Ah (2 x 105 Ah).

Not a huge difference, but an increase in capacity nonetheless.

There is one marketed by Interstate.
Approx 1000 AH
Weighs ~600 lbs.

I used them for UPS for Automatic Test Equipment. I could draw 10 Amps continuously for 48+ hours in the event of a power failure.

12thgenusa wrote:

I am still wayne_tw wrote:
When using two 6 volt batteries wired in series, you double the volts but the amp hours remain the same.

When using two 12 volts wired in parallel, you double the amp hours but the volts remain the same.

Therefore, using two 12 volt batteries you will have greater capacity for the size of the battery bank than using two 6 volt batteries.

While the first two sentences are true, the third is not necessarily true. A 12-volt battery closest in size to a 6-volt GC2 has about 100 Ah. Two will give you 200 Ah. Two GC2s will give you 220 to 235 Ah at 20 hr rate.

That was my experience. I guess that somewhere you can buy 12 volt deep cycle batteries with more than 100-105 Ah capacity, but I couldn't find any. On the other hand, there were plenty of 6 volt golf cart batteries with 225-235 Ahs to choose from. I figured I would go for the 235 Ah over the 210 Ah (2 x 105 Ah).

Not a huge difference, but an increase in capacity nonetheless.

VintageRacer wrote:
I look at 6 volt batteries as half a 12 volt battery in a more convenient package. I can lift a 6 volt 235 ah battery with one hand if it has a handle, lifting an 8D battery (12 volt deep cycle 235 ah) takes deep knee bends and a 5 minute warm up before or a chiropractor visit after... :)

Though I can and fairly easily lift and carry an 8-D the way I used to say it is this:

You take two Six Volt Golf car batteries, lug them to your RV and install you get 12 volt at 230 amp hours

you take 230 amp hours in a single package and attempt to lift and carry it to your RV you get..... A hernia.

Same concept as you posted.

Before my wife died I routinely loaded and unloaded a battery operated scooter, roughly 250 pounds.. By hand, no ramp.

I am still wayne_tw wrote:
When using two 6 volt batteries wired in series, you double the volts but the amp hours remain the same.

When using two 12 volts wired in parallel, you double the amp hours but the volts remain the same.

Therefore, using two 12 volt batteries you will have greater capacity for the size of the battery bank than using two 6 volt batteries.

While the first two sentences are true, the third is not necessarily true. A 12-volt battery closest in size to a 6-volt GC2 has about 100 Ah. Two will give you 200 Ah. Two GC2s will give you 220 to 235 Ah at 20 hr rate.

I second that.

Get 4x GC2 :B

Go with the 6 volt batteries. Millions of golf carts can't be wrong.
Simple math...go with what works and lasts the longest. 6 Volt batteries.