Sunsei Charge Controller CC-10000

A charge controller is used in conjunction with larger solar panels to protect the battery.  It will prevent battery overcharge and night-time reverse discharge if that protection is not already built into the solar panel. A charge controller is not required for small panels under 500mAmps (8W) and depending on the size of the battery may not be required for larger panels. 
Features of Sunsei Charge Controllers
* Intelligent PWM charge control ensures batteries reach max capacity
* Built-in LED indicator instantly displays charging status
* Integrated screw terminal connections for quick and easy installation
* Auto-reset circuit breaker for reverse polarity and surge protection
Sunsei Charge Controller CC-10000
* For solar panels generating up to 10A of current (12V).
* Protects batteries up to 100W of solar power.