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You’re pretty smart. You got a PV solar system and you’re saving money and the environment! So, what do you do on cloudy days and at night? Unless you’re connected to a power grid, you should back up your system with a generator or battery. Batteries are suitable where there is no power grid.

Batteries are more convenient than generators, and can ensure you can use your PV system under more circumstances, but batteries also require some maintenance. PV systems batteries are similar to car, or golf cart, batteries, although they are "deep cycling." That is, they are built to allow more of their stored energy to be used daily. PV systems batteries must be handled with care, much as car batteries. They pose the same risks. They should be stored and their fluid must be checked periodically (in unsealed batteries). They must also be protected from extremes in temperature, especially extremely cold weather. Industrial battery banks store up to as much as three days' worth of energy. A generator can still be used as backup.

Battery-powered PV systems may power dc or ac electrical equipment. An inverter must be added to operate ac equipment. The inverter is “a power conditioning device” between the batteries and the load. A minimal amount of energy is lost during the conversion from dc electricity to ac electricity. However, the inverter causes PV-generated electricity to be similar to that generated by the utility. Therefore, you are free to safely operate ac appliances, lights, and computers.

PV-battery-operated systems have the photovoltaic modules connected to the battery, and the battery connected to the load. During the day, the solar PV modules charge the battery. The charged battery then supplies power to the load (appliances, lights, etc.) as needed. A charge controller keeps the batteries charged properly and helps prolong their life. Charge controllers protect the battery from overcharging or from being completely drained.


Jason Grace
on behalf of the
BascoTec Internet Limited
Technologie Park 13
33100 Paderborn
Germany

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