mAh stands for milli Ampere hour which defines the total capacity of current a mobile battery can deliver in an hour time. To express the total storage capacity, the mAh rating is used in a mobile battery. A higher mAh rating means a higher storage capacity of the battery.

For example, a battery rating of 5000 mAh means, the battery could deliver a maximum 5000mAh current for an hour. If the mobile draws a 500 mAh current for running or playing video, it means the mobile can run for 10 hours (5000/500=10). In that way, a higher capacity battery means, a higher run time for the mobile phone.

## Calculation of Capacity of Mobile Battery

The rating mentioned in the battery in mAh is not enough to define capacity or power. To calculate the capacity of the mobile battery, along with the mAh rating the battery voltage is also required. Generally, the voltage rating of mobile batteries is 3.7 Volt and it goes up to 4.2 after fully charges condition.

To know the actual capacity of the battery, we need to find it in watt-hour. For 5000 mAh and 3.7V battery, the capacity is calculated below.

1000 mAh =1 Ah

5000 mAh=5 Ah

Total Capacity in Watt-hour =Amp-hour X Battery voltage

Total Capacity in Watt-hour = 5×3.7 = 18.5 watt-hour

**How to test mAh capacity of Battery**

After testing the capacity of the battery, the manufacturer has mentioned the mAh and voltage rating in the battery. However, over time the storage capacity of the battery will reduce. After one year, the capacity can reduce by 10 to 20 percent of the rated capacity. It depends on the type of battery and the application of the battery.

We can test the capacity of the mobile battery as per the following methods.

Get the mobile battery, say it is 5000 mAH rated

Connect the load that can draw 500 mA and runs the load constantly.

Say if the load is continuously run for 10 hrs, so capacity is 500×10 = 5000 mAh

Say if the load is continuously run for 8 hours, so capacity is 500×8 =4000 mAh.