The backup for a GridFree installation with MicroInverters

The MicroInverters are low power inverters with max power rating of 230W. They are designed to work parallel to the grid.  For safety, technical and legal reasons, the MicroInverters must disconnect when the grid is down.  They cannot be used as backup invertors. If you wish to keep your equipment running from micro-inverters and to have the energy backup, we suggest adding the UPS (uninterruptable power supply) units to provide the energy during the black-outs.

The drawing shows an example of such an installation where energy is taken from solar panels and the grid, with UPS’s ready to backup the energy. The Inverter is connected to the grid at the INPUT side of the UPS.

NOTE: you cannot connect the micro-inverter to the OUTPUT of the UPS unit. The unit may burn if you connect the inverter to the output of the UPS. Additionally they inverter may also become damaged. The micro  inverter must be connected to the “pure” grid only. 

When the grid is down, the micro-inverter will stop supplying the energy immediately. The UPS will switch to the off-line mode and provide the energy from the backup battery. The the grid is back to normal, the micro-inverters will start working again. In the above diagram, the solar panels are equipped with micro-inverters. (The microinverters [in the back of the panels] are not  drawn in the picture).