Yep, Deep cycle lead acid batteries (used in off grid solar or other RE installations) are rated at something like 93% efficient, but my experience with one brand shows even that is a little optimistic, but its generally close. Jim Ussailis wrote: > Unfortunately, that is not possible. You never get back what you put in. > Even for rechargeable batteries you only get back about 80%. And that's > on a really good day. > > The second law of thermodynamics is a real gotcha. > > Jim U. > > jim at nationalwireless.com -- Thanks, Matt Lampiasi, President 413-303-9167 or http://florenceit.net Florence I.T. - A Community I.T. shop.