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Home battery size calculator
Tell us the average power you'll draw and for how long. We work out the capacity you need and list the stations that cover it.
Add up everything that can run at the same time, including a microwave or kettle if you'll use one.
You need about 3,162 Wh
Energy needed ÷ 85% efficiency.
Capacity needed = average draw (W) × hours ÷ 0.85. Stations must also handle your highest draw. Where no single station is big enough, look at models that take extra batteries.
How to use it
Average draw is the power your devices use on average, not the peak on their labels. A full-size fridge runs its compressor on and off and averages around 70 W. Use the appliance wattage chart or a plug-in power meter to find yours.
Highest draw is the most you'll ever pull at once. A station shuts off if this goes above its continuous output, no matter how much battery is left.
The 85% figure covers losses in the inverter that turns battery power into household AC power. If you run 12 V or USB devices directly, you'll get a little more.
Worked example
Fridge (70 W) + router and modem (12 W) + three LED bulbs (20 W) + phone charging (10 W) = 112 W. For 24 hours: 112 × 24 = 2,688 Wh, divided by 0.85 = about 3,160 Wh. That's more than any 2 kWh station, so you'd need the EcoFlow Delta Pro 3 or a 2 kWh model with an extra battery.