A Grid-tie solar system provides a source of electricity that can be used in parallel with the electricity grid.
Usually, the system setup allows for solar energy to be used as primary source - in other words first solar electricity, then grid electricity.
Excess solar electricity can also be supplied back into the grid - provided official approval is given by the grid owner.
A Grid-tie solar system with battery provides a source of electricity that can be used in parallel with the electricity grid.
Excess solar electricity is stored in a battery to use when there is not sufficient solar electricity available to meet demand.
Usually, the system setup allows for solar energy to be used as primary source, with battery power as second primary source - in other words first solar electricity, then battery and lastly, grid electricity.
Excess solar electricity can also be supplied back into the grid - provided official approval is given by the grid owner.
An Off-grid solar system consist of a grid-tie solar system with battery backup. The system is not connected to an electricity grid.
Excess solar electricity is stored in a battery to use when there is not sufficient solar electricity available to meet demand.
As the system is not connected to an electricity grid to provide when solar and battery backup is not sufficient, it is normal to connect a diesel generator to charge the batteries when state-of-charge of the batteries reaches a minimum level.
