This surprises a lot of new solar owners: if your house has rooftop solar panels but no battery, the panels almost certainly go dark the moment the grid does too — even in the middle of a sunny day. That's not a malfunction. It's a safety requirement.

Why grid-tied solar shuts off in an outage

Most residential solar installations are grid-tied: the panels feed power into your home's system and any excess flows back onto the utility grid. If the grid goes down, utility crews need to work on de-energized lines — so grid-tied inverters are required by code to automatically shut off during an outage (a safety feature called "anti-islanding"), even if your panels are still producing power.

What actually keeps solar working during an outage

Two setups solve this:

  1. A home battery with backup capability (Tesla Powerwall, Enphase, Bluetti or similar) sits between your panels and your house, and is specifically designed to island itself from the grid during an outage — it keeps charging from the panels and powering your home independent of the grid.
  2. A portable solar generator setup — a power station paired with portable solar panels — is completely independent of your home's wiring and the grid by design. It never had a grid connection to "lose", so it works exactly the same whether the power is on or off.

For most homeowners without an existing battery, option 2 is the faster and far cheaper path to solar-backed outage power — see our wattage calculator to size a power station, then pair it with a portable solar panel to recharge it during the outage itself.

How many solar panels does it take to recharge a power station?

A common 100W portable solar panel, in good direct sun, produces roughly 60-80W of real-world output after losses — recharging a 1,000Wh power station from empty takes around 13-17 hours of good sun, or a full day. Pairing 2-3 panels cuts that closer to 5-7 hours. This is meaningfully slower than wall power, which is why solar recharging is best thought of as "extending" your runtime during a multi-day outage, not a fast top-up.