Converter Allegro

kenwat1967 wrote:

I have noticed here and in other discussions of folks using 2 x 6v in series to get the 12v. I understand series and how that makes 12v but what is the advantage over 2 12v in parallel?

Thanks

A lot of it has to do with what batteries are commonly available. The 6V batteries usually used are golf cart batteries, and because there are many golf carts out there they can be had for quite reasonable prices. These are deep cycle batteries, while the generally available 12V RV batteries are much closer to starting batteries and less robust under rough operating conditions (deep discharges and the like). There are 12V deep cycle batteries available, but they're not too common and are relatively expensive.

Basically, a pair of 6V golf cart batteries often gives the best bang for the buck in practical terms and is a reliable setup. Some people prefer the dual 12Vs on the theory that if one goes bad (shorted cell or whatever), they have a backup they can use; however, in practice far too often the bad battery draws down the good one and makes the converter work overtime trying to charge them and the end result is two bad batteries, so I'm not convinced it's really an advantage in practice.

Costco and Sam's Club both sell (in most areas, at least) 6V golf cart batteries for around $90 or so apiece, rated for 220 Ah (at 6V, so a pair wired in series is 220 Ah at 12V).