I was looking at those in the Northern Tool & Equipment catalog and
noticed
that there's also a controller avialable so you don't over charge your
batteries, some of the panels say that the controller is required.

The $40 version has a circuit built-in that supposedly prevents
over-charging or "voltage back-flow" (or whatever you call that...).
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"