Morningstar Sunguard 4.5 Solar Charge Controller IP65 Waterproof:
Sunguard 4.5 from Morningstar is designed for the harshest environments. A 12v solar charge controller that is fully resin potted for complete water resistance it can be mounted safely in the knowledge that it will protect your battery and solar panel from problems.
Morninstar are known for their great warranty and backup, with this behind their simplest product you can be assured of reliability. Comes simply with 4 wires for connecting to the solar panel and battery. No fancy display or systems to go wrong, just simple charge protection. Can be used with 12v panels up to 40w.