Quote Originally Posted by paulmartin483 View Post
Yups I am also trying to design a solar power battery charger that won't overcharge batteries. I've worked out how to make a basic solar charger with solar panel, blocking diode, voltage regular, battery, but I can't figure out how to prevent the batteries from overcharging if I leave them out. I was thinking that an NPN transistor might be useful as a switch, but I don't know where to start.Any suggestions.
Suggest a Morningstar TS45 or a Xantrex C40 charge controller. These monitor the battery voltage/charge, no worries about overcharging. If you are wanting to build a charge controller, check out www.otherpower.com forum, I'm sure you can find a schematic for one. Hugh Piggot, a well know small wind turbine designer posts over there. Or google Hugh Piggot.

What do you have for panel(s), batteries? Voltage?

The link you provided, do you work for that company? Do you have a Southwest wind turbine?