How this solar battery size calculator works
Required delivered energy equals average load multiplied by backup hours; rated battery capacity is adjusted for usable depth and system efficiency.
How to use it
- Average backed-up load. Enter the value in kW.
- Desired backup time. Enter the value in hours.
- Usable battery capacity. Enter the value in %.
- Inverter/system efficiency. Enter the value in %.
- Request the result. Add your email, then select “Email & show my result.”
What to do with the number
Actual backup time changes with variable household load, surge demand and battery operating limits. Build the load estimate from the circuits you actually plan to back up rather than whole-home peak demand.
Planning estimate
Use this result as a starting point, not a guarantee. Product specifications, site conditions, manufacturer guidance, local codes, taxes, labor, tolerances, and rounding can change the real requirement or cost.