This suggests that a 20% increase in battery size is needed for a 5G phone to achieve the same endurance as a 4G variant (assuming everything else is equal). The Redmi executive adds that Qualcomm's flagship 800-series processors consume 20% more juice than an upper mid-range Snapdragon 700-series chipset. So when taken together, this means a 5G flagship will consume significantly more power compared to a mid-range 4G phone, which means battery capacity and optimizations are key for high-end 5G phones.
https://www.androidauthority.com/redmi-5g-4g-battery-life-1098280/
https://www.androidauthority.com/redmi-5g-4g-battery-life-1098280/