The short answer
- Solar alone turns off in a blackout. "Most solar systems will automatically power down" during a shutoff, for line workers' safety (CPUC).
- A battery with a backup gateway keeps essentials running: one battery typically runs priority loads for "24 to 48 hours", and solar can recharge it during the day.
- Whole-home backup with air conditioning usually takes two or more batteries.
- Utilities in fire areas offer backup help: SCE's Critical Care Backup Battery for medical needs, and SDG&E programs for customers in high fire-threat districts.
Who gets shutoffs
Public Safety Power Shutoffs (PSPS) cut power in high-risk wind conditions, mostly in the CPUC's High Fire-Threat Districts (map). SCE says about a quarter of its service area is high fire risk, and it notifies customers 3 days ahead, again 1–4 hours before a shutoff, and at restoration (SCE).
Sizing a battery for outages
| What you back up | Typical need | Batteries (about 13.5 kWh each) |
|---|---|---|
| Fridge, lights, internet, phones, a few outlets | 5–10 kWh a day | 1 |
| Plus a well pump, a gas furnace fan or medical equipment | 10–20 kWh a day | 1–2 |
| Whole home with central air | 25–50+ kWh a day | 2–4, plus solar to recharge |
Daily needs are rough planning ranges; your installer should size from your own use. Battery power limits also matter: a large air conditioner's start-up surge needs enough power, not just energy.
Backup options compared
- Battery with solar: silent, automatic, recharges from the sun, and saves money every day on time-of-use rates.
- Portable power station: cheap and simple for a fridge and phones; SCE and SDG&E have offered rebates for these in fire areas (SDG&E).
- Generator: the most energy for the money, but fuel, noise and carbon monoxide risk.
The CPUC cites installed battery systems at $7,000 to $20,000 or more (CPUC). What owners here paid: home battery cost. Compare models in Powerwall vs. Enphase vs. FranklinWH.
Checked against official sources on Oct 1, 2026. Sources are linked in the text. Not legal, tax or financial advice.