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What is a Solar Charge Controller?

A solar charge controller is a solar-powered voltage and current regulator. They are used in off-grid and hybrid off-grid applications to regulate power input from PV arrays to deliver optimal power output to run electrical loads and charge batteries. Solar charge converters are also commonly called solar charge regulators.

What Does a Solar Charge Controller Do?

Solar charge controllers maintain batteries at their highest state of charge without overcharging them to avoid gassing and battery damage. Learn more by watching our on-demand webinar below, and by reading the additional information on this page.

Reliable charging to maintain battery health and extend battery life is affected by how well, and how fast, the controller’s software controls the electronic component hardware. Battery and PV voltage and current can change in split seconds and the power electronics in the controller must be able to respond fast enough to accommodate these changes.

Most people don’t see or recognize dramatic voltage and current changes going on within their controllers, but if they did have the scopes and sophisticated monitors that could show what is actually happening, they could tell which controllers are going to have the best effect on battery life.

You can have the best batteries and best modules in the world, but they’re only as reliable as your controller. A poor controller can cause battery failure and complete failure with your entire solar system. The best solar charge controllers extend battery life for many years beyond their normal life expectancy, whereas inferior controllers cause premature battery failure and can render your PV system inoperable.

The charge controller generally represents about 10% of your total off-grid power system costs, whereas batteries can be about 40% of your first-time cost and 80% of your lifetime costs. So, the small amount of money you might save deploying a cheaper charge controller will pale in comparison to the money and time wasted on battery replacement. You can use the best PV modules, batteries, wiring, and loads, but their capabilities will be restricted by the quality of the charge controller.