Sunlight Backup


Sunlight backup is a new feature from Enphase that allows you to run your solar panels when the power goes out. This differs from most solar setups, which are required by law to shut down when the power goes out in order to prevent sending electricity into the grid that could cause injuries to workers.


Sunlight Backup works out well for some customers, but it has limitations. Read on to learn about equipment needed, Sunlight Backup limitations, and Project Solar’s recommendations.


Sunlight Backup Equipment and Cost


To get Sunlight Backup, you need Enphase IQ8+ microinverters (standard Project Solar equipment), and an Enphase System Controller 2. 


Together, the IQ8+ inverters and the System Controller 2 “island” your solar panels from the grid during an outage. This prevents the panels from sending power to the grid, but lets them send it to your home instead.


The cost of the System Controller 2 and the extra labor to install it usually comes out to $5,000.



Unfortunately, the capabilities of Sunlight Backup are limited. The system can only power about 4-8 outlets while the grid is down, and power will only be provided if the sun is shining. 


In addition, the extra cost of the System Controller 2 means that, while you may have a small amount of added security during an outage, your system will save you less money.




Because of its limitations, Project Solar rarely recommends Sunlight Backup as a stand-alone feature. However, the good news is that the same capabilities that allow the Enphase IQ8+ inverters to provide Sunlight Backup also allow them to expand the capabilities of batteries.


For customers who want Sunlight Backup, we usually recommend a 3.36kWh battery instead (where available). This will provide all the benefits of Sunlight Backup (you will be able to use your panels during outages), but you’ll be able to back up more, and it won’t matter if the sun is shining.


For more information on how IQ8+ inverters can work with a battery, check out this use case document from Enphase: System Use Cases for IQ8 Microinverters

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