Solar and Off Grid Backup

A. Yes. Your solar system produces power during the day. Production decreases if the sky is overcast and stops when the sun goes down. A backup generator can charge the batteries when solar can't. This might be at night, during periods of heavy power use, or during the day when an overcast sky reduces solar power to charge the batteries.

A. If you are entirely off grid, wiring is less complicated. Typically, a controller/inverter receives power from the solar arrays and uses it to charge a battery bank. An inverter, which could be part of the controller, converts battery DC power to AC for the home. If battery voltage drops below a set level, the controller starts the generator and charges the batteries. At full charge, the controller shuts down the generator. A grid-tied solar system is more complex and generally requires an installer or licensed electrician.

A. Any generator capable of a two-wire start can serve as a backup generator for the solar system provided the system is capable of controlling the generator. It is also possible to charge batteries by connecting the generator to the inverter charger through a manual transfer switch. In this case, the homeowner starts the generator manually when the battery voltage drops below the safe level.

A. A solar system can only charge the battery bank when the sun is shining. The solar array power capacity limits the output to the batteries and home. If the sun is not shining and the batteries are low, the backup generator for the solar system charges the batteries.