Electrical
Battery Runtime Calculator
Estimate battery runtime in hours from capacity in Ah, nominal voltage, load power in W, and usable depth of discharge, with a worked example.
How it works
t(h) = capacity(Ah) × V × DoD / load(W)
A 100 Ah, 12 V battery supplying 50 W at DoD = 0.8 gives t = 100 × 12 × 0.8 / 50 = 19.2 h.
Nominal capacity times voltage estimates stored energy in Wh. DoD selects the usable fraction; 0.8 means 80%.
FAQ
Is 0.8 the same as 80%?
Yes. Enter depth of discharge as a fraction from 0 to 1. The default is 0.8.
Are inverter losses included?
No. Use power drawn at the battery terminals to include converter losses in the load value.
Why can actual runtime be shorter?
Temperature, aging, discharge rate, voltage sag, and cutoff settings can reduce available energy. This is an ideal constant-load energy estimate.