Next out is the motherboard, with the battery piggybacking along for the ride.

The Mi Watch power cell (left) packs in 2.167 Wh (560 mAh @ 3.87 V), which in terms of sheer capacity leaves the 1.129 Wh from the 44 mm Apple Watch Series 5 (right) far behind.

The Snapdragon 3100, its co-processor, and power management sub-system also seem to play a role for longer battery run time.