The surprise many solar owners get
Here's something many solar owners only find out during their first blackout: ordinary rooftop solar turns off when the grid goes down. Even on a bright, sunny day, it won't run your house or charge your car.
The good news is that there are ways around it. This guide explains why your panels shut off, what your options are, and how long each one can keep your lights, and maybe your car, going.
Why your solar panels shut off in a blackout
Most home solar systems are "grid-tied." They're connected to your utility's power lines. When the grid fails, safety standards that utilities require (UL 1741 and IEEE 1547) make your solar inverter shut down automatically.
The reason is simple: line workers are out repairing the wires. If your panels kept pushing power into those lines, they could injure someone who thinks the lines are dead.
To use your solar in an outage, you need equipment that cuts your house off from the grid first. This is called "islanding": your home becomes its own little island, safely separated from the street. Once that happens, your panels can switch back on.
Your options at a glance
Costs are rough. Your installer will give you a real quote.
| Setup | What it can power in an outage | Can it charge your EV? | Rough extra cost |
|---|---|---|---|
| Solar only (no battery) | Nothing. It shuts off. | No | None |
| Solar + home battery | Your home, or the circuits you choose. Solar refills the battery by day. | Slowly, only with spare solar | About $13,500 for a Powerwall 3 |
| Enphase Sunlight Backup | A few essential outlets, only while the sun shines | No | Extra Enphase equipment |
| EV that powers your home (V2H) | Your home, from the car's big battery | It is the EV | Thousands. For example, Tesla quotes about $1,950 for hardware plus $2,000–$4,000 to install without a Powerwall |
| EV with outlets (V2L) | A few appliances on extension cords | It is the EV | Usually none |
Solar + a home battery
A battery system, like a Tesla Powerwall or Enphase IQ Battery, comes with a switch (Tesla's is called the Backup Gateway) that islands your home the moment the grid fails. Your panels then power the house and refill the battery during the day. If there's spare solar, you can charge your EV slowly too.
Enphase Sunlight Backup
Enphase offers a setup that gives you a little power straight from your panels, with no battery. But it only works while the sun is out, the power can change from minute to minute, and it's meant for a few essential plugs. It's not steady or strong enough to charge an EV.
Your EV powers your home (V2H)
"Vehicle-to-home" means using your car's big battery as your home's backup. You need a special two-way charger and backup equipment installed. Some examples:
Ford F-150 Lightning: works with Ford's Charge Station Pro and Home Integration System. Ford stopped building the electric Lightning in December 2025, but existing trucks still work.
Tesla Cybertruck, and new Model 3 and Model Y vehicles ordered in the US on or after October 1, 2026: these use Tesla's Powershare. The Model 3 and Model Y need a Powerwall 3 and a Wall Connector; if you already have both, no extra hardware is needed, but you must ask Tesla to turn the feature on.
Chevrolet Silverado EV and other GM EVs: these work with GM's own home backup equipment.
With some setups, your solar panels can also recharge the car during a long outage, but that needs compatible equipment, so ask your installer.
Your EV has outlets (V2L)
Don't confuse V2H with "vehicle-to-load." Cars like the Hyundai Ioniq 5 let you plug normal extension cords into the car to run a fridge, a microwave or a few lights. It's very handy in an emergency, but it can't power your home's main electrical panel, and it won't switch your solar back on.
How long will each setup last?
Here's the worst case: a blackout with no sun at all. We used an average US home, which uses about 30 kWh of electricity a day (EIA: 10,791 kWh a year).
| Backup source | Usable energy | Whole home (about 30 kWh a day) | If you cut back to essentials |
|---|---|---|---|
| Solar with no battery | 0 kWh | 0 days | 0 days |
| One Tesla Powerwall 3 | 13.5 kWh | About 11 hours | About a day (at around 10 kWh a day) |
| Tesla Model 3 / Model Y with Powershare | Car battery | About 2 days or more (Tesla, from a 90% charge) | Longer |
| Ford F-150 Lightning Extended Range (V2H) | 131 kWh | About 3 days (Ford) | Up to about 10 days with solar or rationing (Ford) |
What the numbers mean
"Essentials" means things like the fridge, lights, Wi-Fi, fans and phone chargers, with no central air or electric heating. It's our rough estimate of around 10 kWh a day; your home may differ. The Tesla and Ford figures are the companies' own estimates.
A single home battery is great for getting through a night. But don't use it to charge your car at full speed. A Level 2 charger pulling about 11 kW, plus your house, can empty a 13.5 kWh Powerwall in about an hour. That's the power you'd want for your fridge tonight.
An EV like the Lightning holds about ten times as much energy as one Powerwall, which is why it can run a home for days.
How to make your backup last longer
Turn off the big loads: central air, electric heating, electric ovens, dryers and pool pumps use the most power. Running only essentials can stretch your backup several times over.
Let the sun help: if the sun comes out after the storm, your panels can refill a home battery, or a compatible V2H setup, each day. Used carefully, solar + battery or solar + V2H can carry you through a long outage.
Keep the car charged before storms: if a hurricane or ice storm is coming, charge your EV to a high level ahead of time. A full car is your biggest backup battery.
Set a reserve on your home battery: most battery apps let you keep part of the battery saved for outages, so it's never empty when the grid fails.
An example: two neighbors after a Florida hurricane
Mike lives in Florida. He has an 8 kW solar system on his roof and a Tesla Model 3 in the garage, but no battery. After a hurricane, his power was out for four days.
The irony? It was sunny the whole time. His panels could have made about 35 kWh a day, enough to charge his car and run part of his air conditioning. But with no battery or backup equipment, his system stayed off to protect the line workers. Mike sat in a hot house with a car he couldn't charge.
Two streets away, his neighbor had a Ford F-150 Lightning with Ford's Charge Station Pro and Home Integration System. When the grid failed, the system switched the house over to the truck's battery automatically. It kept the fridge, lights and air conditioning going for about three days.
Same storm, same sunshine, very different week. The difference wasn't the solar panels. It was the backup equipment.
(Mike and his neighbor are examples, not real customers.)