Battery runtime explained
Convert mAh to Wh (÷1000 × V), then divide by load watts. Example: 5,000 mAh at 3.7 V is 18.5 Wh; at 10 W draw, runtime is about 1.85 hours.
Real-world factors
Heat, age, and discharge rate reduce usable capacity. For critical designs, derate by 20% or use the Charging Time calculator to plan recharge.