Ok let me put it simply
But one BIG battery and when it dies you got no battery
Buy two smaller batteries.. Odds are you pay less and when ONE of them dies, you may or may not loose the other one right away.
But... With one the odds of loosing everything when it dies are 1 in 1. 100%.
With two, closer to 25 percent
Though you should replace 'em both when that happens. if, as happened with me, it's between pay days, and/or it is not convenient to get to the battery store.
you are not SOL. My best recommendation if you have the room, 2 pair six volt.
