Wh and mAh: Understanding Battery Capacity
When it comes to rechargeable batteries, two common terms are often used to describe their capacity: Wh (Watt-hours) and mAh (milliAmpere-hours). But what do they mean, and how do they relate to each other?
What is Wh (Watt-hours)?
Wh is a unit of energy that represents the total amount of electricity that a battery can supply. It's calculated by multiplying the voltage (in volts) by the current (in amps) and the time (in hours) that the battery can supply that current. In other words, Wh is a measure of the total amount of work that a battery can do.
What is mAh (milliAmpere-hours)?
mAh is a unit of electric charge, and it represents the amount of electric charge that a battery can hold. The "milli" prefix means "one-thousandth," so 1 mAh is equal to one-thousandth of an ampere-hour. In simpler terms, mAh is a measure of the capacity of a battery to store electric charge.
The Relationship Between Wh and mAh
While Wh and mAh are related, they are not directly interchangeable. However, we can use the voltage of the battery to convert between the two units.
Formulas:
- Wh = mAh * V (voltage)
- mAh = Wh / V (voltage)
For example, if a battery has a capacity of 2500 mAh and a voltage of 3.7V, its Wh rating would be:
Wh = 2500 mAh * 3.7V = 9.25 Wh
Conversely, if a battery has a Wh rating of 10.5 Wh and a voltage of 3.7V, its mAh rating would be:
mAh = 10.5 Wh / 3.7V = 2838 mAh
Conclusion
In conclusion, Wh and mAh are both important units of measurement for battery capacity, but they represent different aspects of a battery's performance. Wh measures the total amount of energy that a battery can supply, while mAh measures the amount of electric charge that a battery can hold. By understanding the relationships between these units, we can better compare and choose the right batteries for our devices.
