The Redmi K40 has better battery life than the Mi 8.
Redmi K40 battery capacity is 4520mAh, support 33w fast charge, full charge takes 64 minutes, 5 hours of comprehensive power consumption is 36%. Mi 8 battery capacity is 3400mAh, does not support fast charge, full charge takes 98 minutes, 5 hours of comprehensive power consumption is 56%.
The k40 battery is more than 1,000 mA less than the Mi 8 battery, the 870 has 20 percent higher performance than the 865, and the public consumption is 25 percent lower.