Solar Battery Bank Sizer

Estimate nominal battery storage and amp-hours from daily energy use, autonomy, usable depth of discharge, and efficiency. Use the explicitly labelled inputs below; rates, dimensions, and costs are assumptions, not live quotes.

Enter your values in the calculator fields to get an instant result.

Calculator guide

Estimate nominal battery storage and amp-hours from daily energy use, autonomy, usable depth of discharge, and efficiency. Use the explicitly labelled inputs below; rates, dimensions, and costs are assumptions, not live quotes.

Formula or method

Usable energy target = daily energy use × autonomy days. Estimated nominal battery capacity = target ÷ (depth-of-discharge fraction × efficiency fraction). Amp-hours = nominal kWh × 1000 ÷ DC voltage; module count = ceiling(nominal kWh ÷ module capacity).

How to use this calculator

  1. Set Daily Energy Use (kWh/day). The interface starts with 10; replace it with the value for your scenario.
  2. Set Days of Autonomy (days). The interface starts with 2; replace it with the value for your scenario.
  3. Set Usable Depth of Discharge (%). The interface starts with 80; replace it with the value for your scenario.
  4. Set Overall System Efficiency (%). The interface starts with 90; replace it with the value for your scenario.
  5. Set Battery Bank DC Voltage. Available choices: 12 V, 24 V, 48 V.
  6. Set Nominal Capacity per Battery Module (kWh). The interface starts with 5.12; replace it with the value for your scenario.
  7. Compare the result with the worked example, then vary one assumption at a time so you can see what changes.

Worked example

Enter Daily Energy Use = 10 kWh/day; Days of Autonomy = 2 days; Usable Depth of Discharge = 80 %; Overall System Efficiency = 90 %; Battery Bank DC Voltage = 48; Nominal Capacity per Battery Module = 5.12 kWh. With those assumptions, the calculator gives Usable Energy Target: 20 kWh; Estimated Nominal Battery Capacity: 27.78 kWh; Approximate Bank Capacity: 579 Ah at 48 V; Battery Modules at Entered Size: 6. These outputs are calculated from the same implementation as the interactive tool.

Understanding the result

In this example, Usable Energy Target is 20 kWh. Estimated Nominal Battery Capacity is 27.78 kWh. Verify measurements, manufacturer coverage, packaging, local code, and site conditions. Quantity and budget estimates do not certify structural or electrical safety.

Limitations and assumptions

  • Verify measurements, manufacturer coverage, packaging, local code, and site conditions. Quantity and budget estimates do not certify structural or electrical safety.
  • The worked example demonstrates the stated assumptions, not a recommendation about your personal circumstances.

Frequently asked questions

Which inputs should I check first?

For Solar Battery Bank Sizer, check Daily Energy Use, Days of Autonomy, Usable Depth of Discharge, Overall System Efficiency, Battery Bank DC Voltage, Nominal Capacity per Battery Module. Keep the displayed units and select options consistent; do not treat default values as recommendations.

Why might my result differ from another tool?

Compare the other tool's solar battery bank sizer method, input units, rounding and assumptions. A matching title does not guarantee that both tools answer the same question.

Does a linked reference certify this result?

No. A reference can explain a formula or provide background for Solar Battery Bank Sizer, but it does not endorse this website, validate personal inputs or establish professional suitability.

Sources

Educational and planning information only. Sources are attributed background or formula references, not endorsements. Verify consequential decisions with an appropriate qualified professional.