Off grid system is totally independent system, which is not connected to a grid. This system is mainly useful in remote areas, mobile power station, remote tollgates, etc. in off grid system solar power generated in daytime is stored in a battery bank for night time usage. The battery bank and solar array has to be designed as per appliances used.
Anyway the electrical usage should be monitored and used within the system capacity provided. This system should be designed for uniform charging of the battery and also should avoid deep discharge of the battery. This system requires regular maintenance of the battery provided.