UV Radiation Health Tester for fully charging my boat's battery while climbing. Even sitting for hours in the middle of a lake with the engine off listening to music works great to keep the battery charged. Connector tip: I used several RC battery connectors (like this CTMF 7.2V Tamiya connector kit) between the panel and the controller. I also made an extension with these connectors that allows me to place the panel in different places on the boat (open bow). Contrary to one of the previous reviewers, on my controller the green LED lights up when the battery is fully charged, the orange one lights up while charging. The only thing I see in this controller is the replacement of soldered wires with screw terminals.