The SP50-L 50 W solar panel is a photovoltaic power source capable of recharging batteries. It is used for our CS110 Electric Field Meter or other systems that require 50 W solar panels. The SP50 allows unattended operation of systems in remote locations, far from ac electrical sources. This solar panel needs to be used with either a 18529 Morningstar SunSaver, CH200, or CH150 regulator.