Two 6 volt batteries or two 12 volt batteries ??

SoundGuy wrote:

RasMouSein wrote:
People go for the 6v because (story goes) of the footprint, they tend to be taller and fit in the same rack. Therefore more amp/hour in the same place.

Closer to the truth ... many go for two 6 volt GC-2s because pundits here on the forum tell them that's the "better" way to go. :S In reality there's much more to the story and a pair of properly selected G31 12 volts in parallel, some of which are in fact true deep cycle despite what the "experts" here will tell you, could serve some just as well or better. Aside from the obvious advantage that if one 12 volt fails you can still "fly", another is that 12 volt jugs usually have less internal resistance, which in turn means if you're using those batts to power an inverter chances are voltage drop under heavy load is going to be less. So too do more expensive AGM batts have less internal resistance. OTOH, a pair of GC-2s will have a smaller footprint and therefore may be easier to mount than a pair of G31s. They generally also offer the biggest bang for the buck, especially flooded, as so many are sold for so many different uses, not just in RVs. So which is "better"? - you be the judge, for your own reasons, not for someone else's. ;)

FWIW, this spring I'm replacing my pooched 10 yr old flooded G27 that's been sitting on the tongue with a single G31 AGM that will be mounted in the front pass through storage compartment where the run to my 1000 watt PSW inverter will be much shorter. I'm installing only one because we most often camp with shore power available, only occasionally without it, but if we dry camped more often I'd run 2 in parallel ... personal choice. :B Keep in mind though that what batteries, how many you install, their AH rating, and charging requirements must be properly matched to the charger you intend to use to maintain those batteries ... don't get that right and you'll be replacing those batteries sooner rather than later regardless of whether they're 6 volt or 12 volt jugs. ;)

yup, if you intend to run heavy loads, like an inverter to run a microwave, 12V wins. First lower internal resistance, second, if you have two in parallel, each sees 1/2 the load further reducing voltage drop.

A typical pair of GC will run a 1000W inverter load till the batteries are down to around 8085% SOC, not down much, while 12V will run till they are down to 50% or more.

In our case, we compromised. we do lots of dry camping so GC gives more cycles and capability to discharge to 75%DOD with 500 cycles or more, but still want to run a microwave. Solution 4 GC for capacity and ability to run the inverter with batteries near 50%.

Now, if we seldom dry camped, or predominately used high inverter loads, IMHO GC would make no sense. a pair of 12V would way less expensive and do a better job.