Understanding mAH / Ah Battery Rating

In electrochemical system (Like electrical batteries), a SI unit is using frequently, which is Ah (Ampere – Hour) or mAH (milliampere – hour). Flowing of 1 ampere steady current or 3600 C charges for 1 hour is equal to 1 Ah. So, mAh is equal to one-thousandth of an ampere – hour or 3.6 C flowing for 1 hour.

Here,

1C (Coulomb) = 1A × 1s.

So, 1 Ah = 60 × 60 × 1C = 3600C [1 hour = 3600s].

And, 1 mAH = (3600 ÷ 1000) C = 3.6C

If you imagine a battery as a fuel tank, mAh is a unit for measuring of how much “fuel” is storing by the battery. mAH or Ah is not a unit of energy. The large number of mAh or Ah means it has the more capacity to supply power to a device.

For example, a battery with 2500 mAh rating, can power a device drawing 100 milliamps for 25 hours, or a device drawing 250 milliamps for 10 hours. If device need more milliamps then the battery drain faster.

Converting of mAH to Watt – hours:

The equation is: Watt – hours (Wh) = (mAh × Volts) / 1000

So, mAH = (Wh × 1000) / V