Originally Posted by chef2sail
Not sure what this means.
Of course you need two 6- volts to get 12 volt current. The advantage of them is that the footprint for the 2- 6 volt is almost the same as 1 12 volt. So for the same footprint you get twice the ah. NOt sure what density has to do with it. The advantage is more for the SIZE...irrespective of weight.
I didn't make it clear enough. I'm quantifying size and I think the statement "GC batteries have more capacity for their size" is misleading. It implies they have some inherent advantage. But it isn't true in terms of size and weight which are the only ways to truly quantify size. I also doubt they're cheaper but I didn't run those numbers.
Sure they may have more capacity for their footprint because they're taller. But it's not like taller is universally better. My two batteries are both in height contained locations where "size" most definitely includes consideration of the 3rd dimension. So in my case, 12V's give the most capacity possible for their "size".
I'm not knocking GC's at all. If they fit better in my boat I wouldn't hesitate to use them. But in terms of the numbers its basically a complete wash between GC's and regular 12V's.