Calculator

Battery Bank Sizing Calculator

By NerdVolt Editorial TeamJune 16, 2026Estimate tool

Accuracy note: The arithmetic on this page is deterministic from your inputs. Solar production, code, utility, incentive, and savings outputs are estimates unless you supply exact equipment specs, tariffs, shade data, and local requirements.

Inputs

Daily critical load (kWh)Days of autonomyDepth of discharge (%)Discharge efficiency (%)Battery module size (kWh)

Result

How this is calculated

Required nominal kWh = daily load × days of autonomy ÷ (DoD × discharge efficiency). Battery count = ceiling(required nominal kWh ÷ module kWh).

Sources

EIA: storage efficiency
EIA: kWh definition