Solar / UPS Runtime Calculator
A pragmatic estimator. It’s meant to be useful, not “perfect.”
Inputs
Estimate
Usable energy1020 Wh
Raw battery energy1200 Wh
Estimated runtime8 hr 30 min
Calculation: (V × Ah × efficiency) ÷ W
What problem it solves
Quick runtime estimates for a given power draw and battery capacity, with assumptions made explicit.
Technical explanation
It calculates usable energy (Wh) from battery voltage × capacity (Ah), then applies an efficiency factor before dividing by load (W).
Limitations
Ignores inverter surge behavior, battery aging, temperature, Peukert effects, and real discharge curves. Treat results as a starting point.