Solar charge controllers are required by virtually all solar power systems that use batteries. Their function is to regulate the power moving from the solar panels to the batteries. This prevents overcharging of the batteries, which then ensures that they remain in good working condition.

The most basic type of charge controller works to measure the battery voltage and opens the circuit to halt the charging process when voltage reaches a certain level. Previously, most charge controllers had mechanical relays, which opened and closed the circuit. Even a project with DIY Solar Panels needs a solar charge controller.

More recent charge controllers use pulse width modulation (PWM) to gradually lower the amount of power sent to the batteries as they start to reach a fully charged state. PWM extends battery life even more, as it reduces stress on the battery. It’s also possible to use a PWM charge controller to keep batteries “floating,” or in a fully charged state, for as long as you need. PWM chargers are more complex, but they tend to last longer, as they don’t have any breakable mechanical connections.

Maximum power point tracking, or MPPT, is the latest advancement in solar charge controller technology. The main advantage of MPPT controllers is their ability to turn extra voltage into amperage. This feature has a couple of significant benefits.

Although 12 volt batteries are the standard for solar power systems, systems using any voltage level can benefit from these features. Most solar panels produce more voltage than is needed by the batteries. When the extra voltage is converted into amps, the charge voltage remains at an optimal level, while the time needed to fully charge the batteries is reduced. This improves the total performance of a solar power system.

Power loss is also largely eliminated with MPPT charge controllers. The lower the voltage of electricity, the more loss it experiences as it moves along wires. The amount of voltage generally differs depending on specifics within the system. MPPT controllers are able to make use of substantially higher voltage. This means that MPPT controllers see less loss. You can save money in your solar power system by building Homemade Solar Panels.

MPPT charge controllers are generally more expensive than older ones, but the improvement in performance is significant. For this reason, they’re highly recommended.

Finally, it can also be possible to prevent reverse-current flow with certain modern charge controllers. Solar panels will stop generating electricity when they are no longer in contact with sunlight, and the batteries can actually start transferring electricity back to them at these times. This power loss can certainly be frustrating. At these times, a charge controller will open the circuit, preventing any reverse-current flow back to the solar panels.