WH, AH , V
I would like to understand how to read those numbers and see how many times a power bank charger can recharge my phone or laptop.
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Wh is Watt-Hours, Ah is Amp-Hours, V is volts.
To explain these you need a bit of basic physics. If you have some current flowing (measured in amps) across some voltage (measured in volts) then the power (measured in watts) is equal to the current multiplied by the voltage. We’d write that as P=IV Where P is power, I is current and V is voltage.
Batteries store electric energy, which watt-hours are a measure of. 1 Watt hour means it can supply a power of 1 watt for an hour (or 2 watts for half an hour or 3 watts for 1/3 of an hour etc). The thing that determines how many times it can recharge your phone is the energy capacity of the battery, and that of your phone. If the energy stored in the battery is 4x that of the phone battery, you’ll get close to 4 full charges out of a fully charged battery (not quite 4 due to inefficiency in the charging process). Amp hours are a related concept, its a measure of the electrical charge that the battery can transfer, 1 amp-hour means it could supply a current of 1 amp for 1 hour. You can convert this to the energy stored by multiplying by the voltage to go from amps to watts (using P=IV).
If you know the voltage is going to be the same, then you can compare batteries based on their amp-hour ratings.
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