In this post we provide a calculator to convert mAh (milliamp hours) to Wh (watt hours).
As well, we explain how to convert mAh to Wh, the formula behind the calculation, and some practical applications of this knowledge.
Calculator
Enter:
- milliamp hours (mAh)
- Voltage (V)
the tool will provide the equivalent number of Wh (Watt Hour)
Background
The relationship between mAh (milliamp hours) and Wh (watt hours) is essential for anyone working with batteries. These measurements indicate the capacity of a battery and are often used to determine how long a battery will last or to compare energy storage.
What Are mAh and Wh?
mAh (Milliamp Hours): This unit measures a battery’s charge capacity. It tells you how much current a battery can deliver over a certain period. For example, a 2000 mAh battery can provide 2000 milliamps (2 amps) of current for one hour.
Wh (Watt Hours): This unit measures energy, combining the capacity (mAh) with the battery’s voltage (V). It represents the total amount of work a battery can perform before being fully discharged.
The Conversion Formula
The relationship between mAh and Wh is determined by the formula:
Wh = mAh × V/1000
Breaking It Down
- Multiply the mAh value by the battery’s voltage (V).
- Divide the result by 1000 to convert from milliamp hours to watt hours.
Practical Example
Imagine you have a battery rated at 5000 mAh with a voltage of 3.7V. Using the calculator the battery can deliver 18.5 watt hours of energy.
Using Wh to Compare Batteries
Knowing a battery’s Wh is crucial for comparing energy storage across different batteries, especially if they have varying voltages. For example:
- A 5000 mAh battery at 3.7V has 18.5 Wh.
- A 5000 mAh battery at 7.4V has 37 Wh.
Although the capacity (mAh) is the same, the second battery stores twice as much energy due to its higher voltage.
Conversion Chart for Common Voltages
| Battery Voltage (V) | 1000 mAh | 2000 mAh | 5000 mAh | 10000 mAh |
|---|---|---|---|---|
| 3.7V | 3.7 Wh | 7.4 Wh | 18.5 Wh | 37 Wh |
| 7.4V | 7.4 Wh | 14.8 Wh | 37 Wh | 74 Wh |
| 12V | 12 Wh | 24 Wh | 60 Wh | 120 Wh |
Applications of mAh to Wh Conversion
- Comparing Battery Performance: Knowing the Wh allows you to understand how much energy a battery can store, regardless of its mAh rating.
- Designing Energy Systems: For applications like solar systems, drones, or portable electronics, Wh helps in estimating runtime and energy requirements.
- Traveling with Batteries: Airlines often have restrictions on battery Wh ratings. Converting mAh to Wh ensures compliance with regulations. For instance, most airlines allow batteries up to 100 Wh in carry-on luggage.
- Power Bank Selection: When buying a power bank, understanding its Wh rating gives a clearer idea of how many charges it can provide to your devices.