Off-grid solar PV systems are incredibly useful for consumers who do not have access to the utility grid and for those who want to fulfil their energy needs through alternative source.
These systems require batteries to store energy. Off-grid systems generate power during the day which is utilized for powering captive loads as well as to charge the batteries.
When solar energy production is lesser than demand, the stored energy from the batteries is used to power loads. The initial cost as well as the recurring cost of an off-grid solar system is higher than a grid-connected solar PV system. These systems can supply output both in AC and DC form depending upon the connected load and designed configuration.
The working of an off-grid solar PV system is explained in the video, below.
Video by: Wholesale Solar, Inc. (YouTube Channel)