Total amp-hour capacity of your battery or battery bank
Total power draw of all connected devices
LiFePO4 allows 80% depth of discharge, lead acid only 50%
Pure sine wave inverters are typically 85-95% efficient
Results
Estimated Runtime
9.2hours
9h 13m of continuous use
Uses Per Day
2.0cycles
If running this load continuously
Energy Used Per Hour
111Wh
Accounting for inverter losses
How to Use This Calculator
- Enter your battery capacity in amp-hours (Ah)
- Enter the total wattage of devices you want to power
- Select your battery chemistry (LiFePO4, AGM, or Lead Acid)
- Adjust inverter efficiency if you know your specific model
Understanding Battery Runtime
Battery runtime depends on several factors: capacity (Ah), voltage, depth of discharge (DoD), and inverter efficiency.
LiFePO4 batteries can safely discharge to 80-90% of their capacity, making them ideal for off-grid use. They also have a flat discharge curve, maintaining consistent voltage until nearly depleted.
Lead acid and AGM batteries should only be discharged to 50% to maximize lifespan. Regularly deep-discharging lead acid batteries will significantly reduce their cycle life.
Frequently Asked Questions
How long will a 100Ah battery run a 100W load?
A 100Ah LiFePO4 battery at 12V provides about 1,024 usable watt-hours (80% DoD). At 100W with 90% inverter efficiency, expect around 9.2 hours of runtime.
Why does battery type affect runtime?
Different battery chemistries have different safe depth of discharge limits. LiFePO4 can use 80%+ of capacity, while lead acid should only use 50% to prevent damage and maintain cycle life.
What is inverter efficiency?
Inverters convert DC battery power to AC. This conversion isn't 100% efficient—some energy is lost as heat. Pure sine wave inverters are typically 85-95% efficient.