Appliances & Utilities calculator
What Solar Battery Size Do I Need?
Use daily energy use, backup days, usable battery fraction to find solar battery capacity.
Enter your measurements
What Solar Battery Size Do I Need uses daily energy use, backup days, usable battery fraction and the other configured measurements to return solar battery capacity with a formula written specifically for this tool.
- Daily energy use — Required
- Backup days — Required
- Usable battery fraction — Required
- System efficiency — Required
Solar battery capacity
Enter the measurements above to calculate solar battery capacity.
How the calculation works
V17 calculation: nominalBatteryEnergyKWh=dailyEnergyUse×autonomyDays/(usableDepthOfDischarge×systemEfficiency). The result is reported as Solar battery capacity.
Worked example
Example: Daily energy use = 8 kWh; Backup days = 2; Usable battery fraction = 80%; System efficiency = 90%. Result: Nominal Battery Energy KWh = 22.22 kWh.
Before you decide
Measure the actual item, opening or body dimension involved. This page calculates the stated geometry or quantity only; product-specific construction or installation details can still affect the final choice. For what solar battery size do i need, the limiting result on this page is solar battery capacity.
Direct measurement/geometry calculation. No external reference is required for the arithmetic itself; the result is derived only from the user-entered measurements and the formula stored in calculationLogicJson.
Frequently asked questions
What does the Solar Battery Size calculator tell me?
It returns solar battery capacity from the measurements entered on this page. The calculation is specific to solar battery size, so the result should be compared with the exact product or specification you are considering.
Which measurements should I take for solar battery size?
Measure daily energy use, backup days, usable battery fraction, system efficiency. Use clear, usable dimensions rather than nominal room or product labels.
Should I round the solar battery capacity?
Keep the calculated value for comparison, then choose a real product that meets or stays within the returned solar battery capacity while allowing for the clearances, tolerances or ratings shown by its manufacturer.