Convert Megawatt-hour (MWh) to Kilowatt-hour (kWh)

mAh (milliampere-hours) measures electric charge capacity, while Wh (watt-hours) measures energy capacity. mAh tells you how much current a battery can deliver over time, while Wh tells you total energy stored. To convert between them, you need to know the voltage: Wh = (mAh × Voltage) ÷ 1000.

Direct conversion between mAh and Wh requires knowing the battery voltage. mAh measures charge capacity (current × time), while Wh measures energy capacity (power × time). The relationship is: Energy (Wh) = Charge (Ah) × Voltage (V). Without voltage information, the conversion is impossible.

To compare batteries with different voltages, use Wh (watt-hours) rather than mAh. Calculate Wh by multiplying Ah by voltage. For example, a 3000mAh 3.7V battery has 11.1Wh, while a 2000mAh 7.4V battery has 14.8Wh - the second battery actually stores more energy despite lower mAh.

Battery capacity naturally decreases over time and charge cycles. Lithium-ion batteries typically retain 80% of original capacity after 300-500 cycles. Factors affecting degradation include temperature, charge/discharge rates, depth of discharge, and storage conditions. Higher temperatures and deeper discharges accelerate degradation.

Manufacturer capacity ratings are typically measured under ideal laboratory conditions. Real-world capacity can vary ±5-10% due to manufacturing tolerances, temperature, discharge rate, and age. Higher discharge rates generally result in lower effective capacity due to internal resistance and heat generation.

C-rate indicates how fast a battery charges or discharges relative to its capacity. 1C means the battery fully discharges in 1 hour, 2C in 30 minutes, 0.5C in 2 hours. For a 1000mAh battery: 1C = 1000mA, 2C = 2000mA, 0.5C = 500mA. Higher C-rates may reduce effective capacity and battery lifespan.

Basic runtime = Battery capacity (Ah) ÷ Device current draw (A). For example, a 2000mAh battery powering a 500mA device: 2Ah ÷ 0.5A = 4 hours. However, actual runtime is typically 80-90% of calculated due to efficiency losses, voltage drops, and battery characteristics.

Nominal capacity is the manufacturer's rated capacity under standard conditions (usually 20-hour discharge at room temperature). Actual capacity varies with discharge rate, temperature, and battery age. Fast discharge reduces capacity, cold temperatures can reduce it by 20-50%, and aged batteries provide less than nominal capacity.