85% default
The calculator starts at 85% usable capacity. Inverter efficiency, battery health, temperature, and load level can lower real output.
How RuntimeStation Estimates Runtime
We show the formula, assumptions, and limitations behind every planning estimate. A result is not a guarantee.
The formula
Usable capacity is not the same as nominal capacity. We start with a planning assumption and let you change it.
Usable energyNominal Wh × efficiency
Average loadRunning watts × duty cycle
RuntimeUsable energy ÷ average load
Duty cycle
Refrigerators and pumps cycle. Heaters and microwaves generally draw full power while on. The calculator uses a preset duty cycle for common loads.
Surge limits
A station may have enough Wh but not enough continuous or surge watts. Missing surge data is marked for verification, not guessed.
Data is checked against manufacturer product pages on November 12, 2026. Prices, bundles, stock, firmware, and specifications can change. Always verify the current product page before buying.