Solar consumers frequently ask, “Will my solar panels work during a power outage?” But, what they really want to know is if solar will keep their lights on even when the power is down. And, unfortunately, the answer is no — solar alone will not shield your home from experiencing power outages, but a solar backup battery will.
What is a Solar Backup Battery?
Solar backup batteries, like the LG Chem Resu10h or the Tesla Powerwall pair with your solar panels to store the excess energy your system produces for later use. Rather than going back into the grid, your surplus energy is stored in your home’s battery. Small and low-profile, these batteries seamlessly integrate into your home’s electrical network without being an eyesore.
Storing your extra solar energy means you can:
- Maximize renewable energy usage and not waste a drop of sunshine.
- Access stored energy during high energy rate hours and power your home for free.
- Keep the power on for certain appliances or rooms during power outages when your panels shut off.
- Access instant and inexpensive energy during an outage as compared to traditional generators.
Read our guide on seasonal Texas power outages and solar backup storage to learn more about why solar panels do not work during power outages.
How do Solar Backup Batteries Work?
Before you can understand how solar backup storage works with your solar panel system, you should first understand how solar panels work.
Solar Panel System
Most solar consumers have “grid-tied” solar systems, which means their solar system is connected to their local electrical grid. When the grid goes down, or it’s dark out, your solar panels will not produce energy; instead, your home will pull power from the electrical grid. Conversely, if your house produces more energy than you use, that excess energy will go back into the grid. This is how solar consumers end up with zero or negative electricity bills (net-metering).
However, with the addition of a solar backup battery, that extra energy will be stored in a wall battery rather than going back into the grid.
Battery Charging: DC vs. AC
Your home is powered by AC (alternating current) electricity, but most batteries need DC (direct current) to be charged up. With a DC battery, like the LG Chem, the DC energy produced by your solar panels immediately charges up the battery. However, when you need to access the stored energy, it must pass through an inverter so your home can utilize the AC power.
Alternatively, many solar backups are AC batteries. An AC battery accepts the alternating current and internally inverts the power to DC for charging. However, when the battery needs to disperse the stored energy, it has to convert it again to AC for home usage. Due to the double conversion, DC batteries are more efficient and less expensive than AC batteries.
The minute your power is down, your battery kicks on. But it is important to remember that a single solar backup battery cannot power most homes during an outage.
The electrical grid powers your home via your distribution panel, which distributes energy throughout your home. When the grid goes down, the solar battery disconnects from your distribution panel and is rewired to a protected loads panel; you get to specify what rooms and appliances are wired to the protected load panel. So, when the power is out, the battery switches on, isolates from the grid, and powers the protected load panel.