[aprssig] backup pwr systems - slightly off-topic

[Joe Della Barba]

You all are *still* over complicating this.
I used to be in the marine electrical/electronics business and most 
boats over 30 feet are plugged into shore power 24/7/365 when not 
underway and have various DC loads running. They do not ruin their very 
expensive battery banks if they have halfway decent chargers. The "smart 
charger" is not fooled by loads to an extent that will boil the 
batteries. Some chargers even have temperature sensors that attach to 
the batteries. Here is just one example - 
http://www.defender.com/product.jsp?path=-1|328|51495|985|316473&id=94183 .
These chargers can be left on permanently with no problem. If you are 
really hardcore, get some batteries like these babies:
http://www.rollsbattery.com/Solar/solarspecs.htm
http://www.rollsbattery.com/Marine/marinespecs.htm

73
Joe N3HGB