Battery Runtime Calculator
Estimate backup runtime from battery capacity and load.
Results
Estimated runtime14.40 hours
Hours + minutes14h 24m
Usable capacity72.00 Ah
System voltage12 V
How runtime is estimated
Runtime ≈ usable amp-hour capacity ÷ load current. Usable capacity includes efficiency and usable-capacity percentage.
Real-world runtime varies due to battery chemistry, age, temperature, discharge rate, equipment efficiency, and manufacturer specifications.
Example
100 Ah, 80% usable, 90% efficiency → 72 Ah usable. At 10 A load, estimate about 7.2 hours (7h 12m).
FAQ
- Why isn’t this exact?
- Peukert’s law, temperature, and chemistry change actual runtime. Treat results as estimates.
- What does series-parallel mean here?
- MVP assumes even battery counts: two-series strings paralleled (voltage ×2, Ah × n/2).