mAh vs Wh. Calculating correct capacityUpdated a year ago

Milliampere-hours (mAh) have recently become the common measure for indicating battery capacity. However, mAh alone doesn't provide a complete assessment because it disregards the influence of voltage in its calculation. For an accurate assessment of battery capacity, it's advisable to employ watt-hours (Wh), which results from multiplying the ampere-hour (Ah) by the battery cell's voltage.

A practical illustration compares a DJI drone battery and a standard power bank.

The specifications of a DJI Mavic Pro battery cite a capacity of 3830 mAh. Initially, one might assume that a power bank with a capacity of 10,000 mAh would be three times the capacity of the DJI drone battery. However, this assumption overlooks the role of voltage. The DJI Drone operates at 11.4 V, while many power banks employ battery cells with a voltage of 3.6V. Notably, Omnicharge products predominantly utilize high-output cells with a cell voltage of 3.7V.

The relevant calculation is as follows:

Wh = Ah x V
(Note: 1000mAh = 1Ah)

DJI Drone capacity = 3.83Ah x 11.4V = 43.6Wh
Generic power bank = 10Ah x 3.6V = 36Wh

This example underscores the potential for misinterpretation when relying solely on mAh to gauge capacity. A case in point highlights that the drone battery possesses a higher capacity despite having notably lower mAh.