1. "mAh" is the unit of battery capacity, and the Chinese name is milliampere-hour (when measuring large-capacity batteries such as lead-acid batteries, for convenience, it is usually expressed as "Ah ", and the Chinese name is ampere-hour).
1mAh=0.001 Ampere*3600 seconds=3.6 Ampere seconds=3.6 Coulombs
2. The coulomb is a unit of electricity. The coulomb is not the basic unit of the international system of units. but the unit derived from the International System of Units. 1 coulomb = 1 ampere second.
The quantity of electricity carried by a current of 1A in 1s, that is to say 1C=1A·s.
3. Power Formula for calculating electrical power: P=UI. The unit of P is the watt W; in a pure resistance circuit, according to Ohm's law U=IR and substituted by P=UI, we can also obtain: P=I*IR=(U*U)/R
1. The most direct algorithm:
1. First get the current from the electrical appliance
2. Divide intouite the capacity of the battery by the current of the electrical device. the result is the usage time
For example:
A 3000mAH battery with a nominal voltage of 5V powers an electrical appliance with a power consumption of 2.5 W and a voltage of 5 V. Its theoretical use life is:
I =P/U => 2.5w/5v => 0.5A => 500MA
3000mAh, that is to say, a current of 3000MA can be discharged for one hour,
3000/500=6 hours
2. Coulomb charge algorithm
C=IS => 3A*3600s => 10800c Coulomb (charge)
10800c*5v=54000w of electrical energy
54000w /2.5w=21600/3600s =6h