Battery Backup Power - Mystery De-Coded

100% Power Reliability

By now it is common knowledge that with most utility interactive PV systems, grid failure will still shut down the entire electrical system. The reason for this is safety; While a utility lineman works to restore power to the grid, we need to make sure that the lines that he works on are not energized by nearby PV arrays. Therefore, the inverter is designed to immediately cut off power flowing into your electrical panel and hence, into the grid. But what about the customer who has invested tens, maybe hundreds of thousands of dollars in renewable energy and the idea of power independence, now without power? We get this question often and the following explanation ensues:

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With a battery backup system, your solar panels will be hard at work charging batteries while the grid is down and your inverter will magically morph your power system into the same type that you would find in an off-grid application. This will give you 100% power reliability and true power independence.

The first picture is of an Outback system and the second is a simple version of a Sunny Island system by SMA. The main difference is that while the Sunny Island system powers the entire house with battery power when grid power is down, the Outback system can be designed to power critical loads only. Powering select critical loads is an advantage in this application because your battery bank can be designed smaller (less expensive) and charged faster by your PV array. However, any energy conscious individual can be careful not to use large load appliances that will quickly drain the battery bank.

The design of such a system is more involved and the cost is somewhat higher, typically 1.25 times the cost of a typical residential grid-tie system. Get a hold of Sierra Solar Systems if you would like a system designed for your application; residential, commercial, or large scale. We specialize in getting the perfect equipment for your application with preferred dealer pricing, comprehensive service and genuine smiles.