mAh (milliampere-hour) is a unit of capacity and mA is a unit of current.
1mAh= Discharge at 1ma current for 1 hour.
Take the battery for example, 3000mAh=3Ah, which means that if you discharge with 3A current, the battery can discharge for 1 hour under full charge. m is millillion, 10 minus 3. A is a unit of current, the ampere. h is a unit of time, 1h=1 hour.
Since several important parameters cannot be determined (even the voltage is not given), only the theoretical time can be calculated.
The mobile phone battery is calculated according to a single core, the voltage is 3.7V, and the capacity is 3000mAh.
Charger output voltage 4.2V, current 500mA (silly charger).
Here is the simplest, most crude algorithm.
3.7V x 3000mAh=11100mWh=11.1Wh (All the electrical energy that the battery can theoretically store)
The output of the charger is 4.2V x 500mA = 2.1W
However, the charger is not charged from 0 to 100% with this power, I assume that the charger is a stupid charge controlled by the op amp (such as LM324), and the charging process has only two stages, constant voltage charging and fixed trickle charging. If it is smart charging, it is more difficult to calculate, because there is also a constant current charging function.
The charger will charge to 90% (2700mAh) at maximum power, and more than 90% will be converted to trickle charging (trickle charging time cannot be calculated).
so, 11.1Wh X 90% =9.99Wh, 9.99Wh ÷ 2.1W=4.75h= 4.75h, this is just the time required to charge to 90%. Trickle charging takes more than 30 minutes at the minimum, so the charging time may be close to 6 hours.
First of all, the actual capacity of the battery is not known, the conversion efficiency is not known, and the trickle charging time can not be determined, so it is simply impossible to calculate accurately. In addition, all factors that may affect the battery case charger, including temperature, have been omitted.
mW and ma are both units of power
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mA and A are both units of electric current
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Two different units are not directly interchangeable
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For example, you can't say how many kilograms are equal to a meter
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For mW and mA to be converted, there must be a voltage V
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1mW=1mA×1V