Steady AC load
Backup request · W
Allowed range: 0.01 to 10000000
Required Battery Capacity Calculator
Work backwards from a backup load and duration to nominal battery capacity.
Open this toolWorking backwards from a load and backup duration gives a nominal storage target rather than just a guessed battery count.
Include the intended energy allowance and inverter idle draw, then choose usable discharge within the manufacturer's limits.
Inputs and controls
Backup duration
Backup request · hours
Allowed range: 0.01 to 10000
Energy allowance
Backup request · %
Allowed range: 0 to 100
Bank nominal voltage
Battery and inverter · V
Allowed range: 0.1 to 2000
Usable depth of discharge
Battery and inverter · %
Allowed range: 0.01 to 100
Inverter efficiency
Battery and inverter · %
Allowed range: 0.01 to 100
DC idle consumption
Battery and inverter · W
Allowed range: 0 to 1000000
How to use
- Enter steady AC load, backup duration and energy allowance.
- Enter bank nominal voltage, usable depth of discharge, inverter efficiency and DC idle consumption.
- Select Calculate result. Read the returned values alongside the assumptions below before copying, exporting or acting on the result.
Why use this tool
The calculation connects the storage target directly to the hours and load you want to cover.
Before relying on the result
Required nominal energy includes the entered allowance and idle draw. Use manufacturer limits to choose usable DoD and discharge capability.
Tool limitations
Required nominal energy includes the entered allowance and idle draw. Use manufacturer limits to choose usable DoD and discharge capability.
Questions
Does capacity alone prove the battery can supply the load?
No. Discharge current, BMS limits and equipment compatibility need a separate check.
What should I check before using Required Battery Capacity Calculator?
Check Steady AC load, Backup duration, Energy allowance and Bank nominal voltage. Use the exact units shown beside the controls and replace any example values with your own inputs.
Source page last modified: 2026-10-01T18:56:35+00:00. This profile describes the tool; use its page to run it.
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