On-grid type of solar power systems are the most commonly used system in residential as well as in commercials sites. There is no need of batteries in this type PV system, but is needs a solar inverter. It is then connected to the public grid. If there is any extra power generated by your solar PV system then that extra power can be feed to the grid and you can earn money for it.

Off-grid system is not connected to the electricity grid directly so, here a battery is needed to store the power which is generated by the panel. Off-grid solar systems must be designed properly so that enough power is generated which could satisfy the requirement of electricity throughout the year also it should have enough battery capacity to meet the electricity requirements, even in the depths of winter when there is generally much less sunlight.

In the Hybrid PV systems, a combination of solar and battery is used this type of PV system are now available in many forms and configurations. Nowadays the system which are already connected to the electric grid can also use a battery storage. The energy which is generated throughout the day can be stored in the battery and it which can be used when there is a complete blackout or at the night time. When the stored energy is depleted, the grid is used as a back-up. Hybrid systems are also able to charge the batteries using cheap off-peak electricity.