The Inverter Runtime Calculator estimates how long an inverter can run a connected AC load using a battery.
Enter battery capacity, inverter efficiency and AC load to calculate usable runtime. Idle consumption can also be included.
How Inverter Runtime Works
Inverters convert DC battery energy into AC power, but the process is not 100% efficient. Some energy is
lost as heat and electronic switching loss. Therefore, the actual usable energy is battery Wh × efficiency.
Formula:
Runtime (hours) = (Battery Wh × Efficiency – Idle Power × time) ÷ Load
Energy Loss Factors
- Inverter conversion efficiency
- Idle running consumption
- Heat loss
- Non-linear AC loads
Where This Calculator Is Useful
- Home inverters
- Solar backup systems
- UPS battery backup
- Off-grid cabins
- RV electrical systems
Frequently Asked Questions
Q: Does inverter efficiency affect runtime?
Yes. Higher inverter efficiency provides longer backup time by reducing conversion losses.
Q: Do I need to include idle consumption?
Idle running power lowers runtime. It becomes important for long duration or low load scenarios.
Q: Can I use Ah instead of Wh?
Yes, simply enter Ah and voltage and the calculator converts automatically to Wh.
Q: What is typical inverter efficiency?
Most modern inverters range between 85% to 95%.
Q: Will appliance surge affect runtime?
Short surges have minimal impact. Continuous watt usage defines the true runtime.
