kW to mAh Calculator

Convert power in kilowatts (kW) to battery capacity in milliamp-hours (mAh) using voltage and time. This tool helps estimate how much battery capacity is needed to supply a specific amount of power.

Understanding kW to mAh Conversion

Converting kilowatts (kW) to milliamp-hours (mAh) allows you to estimate how much battery capacity is required to deliver a specific amount of power over a given time. This is important for battery design, energy storage systems, off-grid power solutions, and mobile device engineering.

What Are kW and mAh?

  • Kilowatts (kW): A unit of power equal to 1,000 watts. It measures how quickly energy is consumed or produced.
  • Milliamp-hours (mAh): A unit of electric charge, representing the battery’s capacity to deliver current over time.

Formula to Convert kW to mAh

mAh = (kW × 1,000,000 × time in hours) ÷ voltage

Explanation:

  1. Convert kilowatts to watts: kW × 1000
  2. Multiply by time (in hours) to get energy in watt-hours (Wh)
  3. Divide Wh by voltage to get amp-hours (Ah)
  4. Multiply by 1000 to convert Ah to mAh

Example Calculations

  • 1 kW for 2 hours at 12V:
    mAh = (1 × 1,000,000 × 2) ÷ 12 = 166,666.67 mAh
  • 0.5 kW for 3 hours at 5V:
    mAh = (0.5 × 1,000,000 × 3) ÷ 5 = 300,000 mAh
  • 2.5 kW for 1 hour at 24V:
    mAh = (2.5 × 1,000,000 × 1) ÷ 24 = 104,166.67 mAh

Why Convert kW to mAh?

This conversion is useful for:

  • Battery Sizing: Designing batteries that can support specific loads.
  • Solar Storage Systems: Calculating how many battery banks are required to store solar energy.
  • Mobile Devices: Matching battery capacity to performance expectations.
  • Electric Vehicles: Estimating range based on battery specs and power draw.

Common Voltages and Use Cases

System Voltage (V) Typical Application
Li-ion Cell 3.7 Phones, drones, laptops
12V DC 12 Cars, solar storage
24V DC 24 RV systems, off-grid homes
48V Systems 48 Telecom, high-efficiency solar banks

Battery Chemistry Considerations

Different battery types (Li-ion, LFP, NiMH, lead-acid) have different voltage profiles. Accurate conversion requires using the nominal voltage of the specific battery chemistry.

FAQs

Can I convert kW to mAh without voltage?

No. Voltage is required to determine how much current is needed to deliver that power.

Is mAh a measure of energy?

No. It is a measure of electric charge. When combined with voltage and time, it indirectly relates to energy.

Is this calculator for AC or DC?

Primarily for DC systems, since battery storage and mAh ratings are based on DC current.

How much mAh is 1 kW at 5V for 1 hour?

(1 × 1,000,000 × 1) ÷ 5 = 200,000 mAh