Use the solar PV charge controller to ensure that while using the power of the sun you do not overcharge your batteries. Overcharging your batteries could potentially cause electrical damage to the devices that you are powering. It also prevents internal crystallization in lead acid batteries. The solar charge controller takes uncertain voltage from a solar power and safely conditions it to charge lead acid batteries. Use this solar charge controller with almost any commercial grade solar panels. Use it with 12v solar panels up to 4A DC. Features * Overcharge protection circuit. * LED charging indicators. * Copper wire terminals for quick connect/disconnect. * Durable design. * Designed for 12v rated solar panels (up to 21voc). * 4A maximum input charging current. Specifications * Weight: 1.4 lb * Dimensions: 3.5" x 4.5" x 1"