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question about power used/capacity of cell phone battery?
hi guys, if a cell phone battery with 957mAh and 3.7V.
957mAh is the battery capacity, isnt it?
So, is it mean that the power require to fully charge the battery is (957 X 3.7)/1000000 = 0.0035 kWh ? (assume the battery is completely empty)
If it is true (need 0.0035kWh power to charge), is that also mean this is the power needed with regardless of the charging time? for example, 2 same capacity batteries may need different time to fully charge the battery, but the power it require is the same, is it truth? Because I am not sure the relationship between charging and the capacity.
Thank you very much!
The nominal battery voltage is 3.7V, determined only by the battery chemistry (probably nickel metal hydride) and number of cells. The 957mAh is the capacity in milliampere-hours. That means it could provide the equivalent of almost 1 ampere for one hour. They are usually rated at "0.1C", so you could reasonably expect to draw one tenth of that (95.7mA) for 10 hours.
Charging is not 100% efficient, so charging at 0.1C would probably take 12-16 hours. That charge and discharge rate are appropriate for maximizing battery life.
Within the limits of the capability of the battery, you can choose whether to charge at a higher power for a shorter time, or a lower power for a longer time.
EEVblog #140 - Battery Capacity Tutorial