On Mon, 31 Jan 2011 14:05:44 -0600, wrote:

harry wrote:

One thing you need to look out for is that when lead acid batteries
are charged, hydrogen gas is evolved.

Cant you avoid lead acid by buying a sealed AGM deep
discharge battery?
A very large percentage of "deep cycle" and "marine" batteries today
are avaoilable as "sterved electrolyte" or AGM type batteries.
Many of these batteries do not gas at all under normal load or
recharge conditions (they are "recombinent chemistry" batteries or
"valve regulated recombinent" batteries.
Virtually all of the "portable power" systems use these batteries,
including the Motomaster power-boxes.