Q&A How Off-Grid Solar Systems Work
 
If it is possible to install a solar system that is independent of the electrical grid. This is called an off-grid system, and it requires that the solar panels are able to produce enough electricity to cover 100% of the energy needs of the buildling. Most homes have higher electricity demand in the evening or at night, so off-grid systems usually incorporate either a battery (to store energy produced during the day), a backup source of energy (like a generator), or both. Off-grid systems are more complex and less flexible than grid-tied systems.
Off-grid systems are most common in remote locations without utility service. Off-grid solar-electric systems operate independently from the local utility grid to provide electricity to a home, building, boat, or RV (or remote agricultural pumps, gates, traffic signs, etc.). These systems typically require either a battery bank (to store solar electricity for use during nighttime or cloudy weather) a backup source of energy (like a generator), or both.  An off-grid solar system must be large enough to produce enough electricity to cover 100% of the energy needs of the buildling.  In all off-grid scenarios, electrical usage must be monitored and kept below the maximum output of the panels and batteries as there is no grid-source to supply excess power.
System components:
> PV panels
> battery bank
> charge controller (to protect the battery bank from overcharge)
> inverter
> required electrical safety gear (i.e. fuses, breakers, disconnects)
> monitoring system to balance energy consumption with production
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