Module 3 · Lithium & sodium-ion battery backup

How much battery do you need, and for how long will it run?

Add what you want to keep running in an outage. Use the watts on each appliance label for the best result.

Indicative estimate, not a design

1 · Appliances

Running watts default to the rated value. Change it if you measured a lower or higher draw.

Hours = how long each appliance runs during the outage (capped at the backup duration). Intermittent appliances such as fridges cycle on and off; duty % is the share of time the compressor or motor actually runs. Start W is the starting surge of one unit.

2 · Backup settings

hours
%
Extra margin above the calculated need.
%
%
%
%
Size for an aged battery, e.g. 80%.
%
Capacity available at site temperature.
How many starting surges can coincide.

3 · Battery and inverter

W
W

Compare battery sizes

Runtime estimates for your current appliances

Plan the whole system

Your appliance list is remembered in this browser tab. The package builder can use it to size panels, inverter and battery together and estimate the total cost.

Open the package builder Panel and inverter sizing