Battery Bank Sizing Tool

Estimate battery bank size from either a manual daily watt-hour total or a row-based load builder.

Public calculator: You can use this tool without logging in. Logged-in builders can save battery planning profiles and optionally link them to a project.

Planning Inputs

Energy accounting

Manual total represents

In separate AC/DC mode, inverter loss applies only to AC loads. Battery reserve affects capacity; Solar receives daily recharge demand before that reserve.

Daily Energy Entry Mode

Manual Daily Energy Total

Build Daily Energy from Loads

Choose whether to enter one total daily watt-hour number or build it from individual component loads.

Manual Daily Energy Total

Daily Energy Use (Watt-Hours)

Use this if you already know your total estimated daily energy demand.

Load Builder

Entry mode: Manual Total

Component Name	Voltage	Qty	Amps	Watts	Hours / Day	Daily Wh	Source	Row
AC or DC load							Manual

Enter amps or watts for each row. If watts is blank, the calculator can derive watts from voltage × amps. Imported project rows are editable after import.

Current row count: 1

Battery Planning Assumptions

Battery System Voltage

Choose the nominal voltage of the battery bank you are sizing.

Days of Autonomy

How many days the battery bank should support the load without recharge.

Battery Chemistry

Your entered discharge limit is preserved when changing chemistry. Review it against your battery specifications.

Max Depth of Discharge (%)

Use lower values for more conservative usable battery capacity assumptions.

Inverter Efficiency

Enter as a decimal ratio, such as 0.90 for 90%.

System Loss Factor

Multiplier for additional system losses. Example: 1.05

Safety Margin Factor

Multiplier for planning margin. Example: 1.10

Reset

You do not need an account to calculate results. Save, load, and project-import features are available only to logged-in builders.

Results

Choose an entry mode, enter your planning assumptions, and select Calculate Battery Bank Size to view estimated battery capacity guidance.

Planning note: Manual total entry and load-builder entry are both supported. Project import is available without changing the overall battery-bank structure.