The Solarstate SRX-12-12 is an industrial-quality, temperature-compensated charge regulator for small and midsized photovoltaic power systems. It uses a low-frequency shunting technique to control up to 12 amperes of array current in 12-volt and 24-volt systems. Two SRX-12 units may be installed in parallel if desired, enabling incremental increase in system size. The SRX-12 is compact, attaching directly to the junction box of Solarex and other photovoltaic modules. Installed in this manner, it is weatherproof and compliant with the requirements of recognized safety rating authorities.