Solar charge controllers keep your batteries safe. A solar charge controller is required for any solar array of 12-Watt or higher. Solar panels are unregulated and can have a-voltage higher than necessary to charge 12-volt batteries. The Nature Power 28-Amp Solar Digital PWM Charge Controller will prevent overcharging of batteries by regulating the-voltage from a 12-volt solar panel to a safe level for charging 12-volt batteries. Pulse Width Modulation (PWM) control provides higher charging efficiency and maintains a higher battery reserve than standard on/off controllers. Designed for use with 12-volt solar panels this solar charge controller is safe for use with up to 28-amp or 450-Watt from a solar array. This controller will also prevent over discharge of your battery as well as protect from high-voltage surges, short circuit and loss of power through the solar panel at night. A digital LCD screen displays charging current, load current, and battery-voltage in 5 second intervals. Two LED lights display charge function and battery status. A load terminal on the solar charge controller let you dedicate one item to run through the controller, when the batteries reach critical-voltage the load will be automatically turned off to prevent a dead battery and allow the solar panel to recharge the battery before the load turns on again. This feature helps to prolong the life of your battery. This charge controller may also be used with 24-volt solar panels and batteries. The charge controller is self-adjusting and will automatically set the charge cycle. You can connect multiple solar panels up to one controller so long as you do not exceed 450-Watt or 28-amp. The charge controller is meant to be permanently connected to the battery and the solar array even when you are drawing power from the battery. Solar charge controllers should installed close to the battery in a dry and ventilated area. This solar charge controller is covered by a 1 year manufacturers warranty.