A lot of Florida homeowners find this out the hard way. The power goes out on a sunny afternoon, the panels on the roof are sitting in full light, and the house is still dark. It surprises people, but it's how most solar systems are designed to behave.
Why the panels go dark
Most home solar systems are grid-tied. The panels make electricity, the house uses what it needs, and anything extra flows out onto the utility's lines.
That last part is the problem during an outage. When the grid goes down, crews start working on lines they expect to be dead. If thousands of rooftop systems kept pushing power onto those lines, a lineworker could be hurt or killed. So the inverters in grid-tied systems are built to sense a grid outage and shut off within seconds. The industry calls this anti-islanding, and it's required by the interconnection standards utilities follow, including IEEE 1547.
The panels themselves are fine. They're just switched off on purpose until the grid comes back.
What a battery changes
A battery lets the house separate itself from the grid during an outage. When the power drops, equipment in the system disconnects your home from the utility lines, and the house runs on stored power instead. With the house cut off from the grid, the panels can safely turn back on and feed the house and the battery.
That's the setup that keeps a solar home running during an outage:
- The grid goes down and the house switches to the battery on its own.
- During the day, the panels power the house and recharge the battery.
- At night, the house runs on what the battery stored.
- When the grid comes back, the system reconnects and goes back to normal.
Why the panels matter in a long outage
A battery alone runs until it's empty. A battery with panels can refill every sunny day, which turns a few hours of backup into a house that keeps running through a long outage.
Do I need panels to have a battery?
You don't need panels to have a battery. A home battery on its own charges from the grid and waits for the next outage. If you're thinking about solar panels with battery backup, sizing them together from the start lets the panels and the battery fit how your home actually uses power.
How much would it run?
That depends on the size of the battery, the size of the solar system and what you want running. Central AC is the big one in Florida. We cover the math in how long a home battery will run your house, and during a free in-home assessment we size the system from your electric bill.