Solar Battery Backup for Power Outages
A solar battery backup plan should start with essential loads, not whole-home guesses. Fridge, lights, router, medical devices, and a few outlets may need far less battery than running central AC for days.
Short answer: many homes start planning around 10-20 kWh of usable battery for essentials, but outage duration and load choices can change that quickly.
What to List Before Sizing
- Essential appliances: fridge, lights, internet, garage door, well pump, or medical equipment.
- Outage duration: overnight backup is different from two-day resilience.
- Solar recharge: daytime solar can extend backup if the system supports islanding.
- Large loads: air conditioning, electric heat, and EV charging can dominate battery size.
Best Next Step
Use the Battery Sizing calculator to estimate usable kWh, then compare the solar array with Panel Count.
Next step: size backup around real loads and outage duration.