How is the power of a battery calculated
A battery that reaches twelve volts but is less than 20ah may not be able to drive.
20ah is the capacity of the battery, not the power. When the current is constant, the larger the capacity, the longer it can be used for power supply.
The meaning of 20ah is that when the battery output current is 20 amps, it can be used for 1 hour, or it can be understood as when the battery output current is 2 amps, it can be used for 10 hours, etc. The product of current and time is 20
When the device requires a high-power battery of 20ah to drive, it indicates that the device has a high operating current, and small capacity batteries may not be able to withstand this high current. If a small capacity battery can withstand the driving current of the device, it can be driven. Just like how you connect more than ten seventh batteries in series to drive an electric bicycle, it cannot be driven.
This is the capacity of the battery, not the power, which means the time it can operate an appliance with a certain power. The length of the operating time depends on the power of the appliance.
In addition to 100Ah, the battery also needs to know the voltage level. This battery can operate for 1 hour at a current of 100 amperes, and the specific power depends on the voltage of the battery. For example, a 12V battery can operate a 1200 watt appliance for one hour with a working current of 100 amperes, and for 10 hours with a working current of 10 amperes. It depends on how much current is used to determine the working time.
The battery does not talk about power, but about "milliampere hour", which refers to the time it can discharge in milliampere hours, which is its electrical energy capacity. The voltage of the new regular No. 5 dry battery is 1.5V, with an internal resistance of about 1 ohm, and the voltage will decrease during discharge. If the discharge current reaches 500mA, a voltage drop of 0.5V will be generated, and the output voltage will only be 1V. The larger the discharge current, the smaller the total discharge capacity and the shorter the lifespan. The continuous discharge life is shorter.
Let me explain it to you from the unit
The unit of power is watts (W), denoted by P=UI and 1W=1V. A (one watt equals one volt) An)
Battery capacity mA. h (milliampere hour) When)
It is obvious that these two parts are different.
Further search for relationships:
Unit of electrical energy and power joules (J)
W=Pt
It can be known that 1J=1W. s=1V. A.s (one joule equals one volt ampere second)
If the voltage of the battery is known, multiply the voltage by the battery capacity to see what you get: unit V.mA. h
In fact, the unit of measurement is essentially the same as that of electrical energy. To convert it:
1V.mA.h=1V*10^-3A*3600s=3.6V.A.s=3.6J
A battery is an energy storage component, and there is no such thing as power. It has a rated capacity, measured in Wh and Wh, which can be obtained by multiplying the voltage by the capacity, such as Redmi
The "12V12AH battery" does not mean that its power is 144 watts (12 * 12)!
12V12AH battery "refers to the capacity of the battery. The rated working voltage of the battery is 12 volts. If the discharge current is 1 ampere, it can be used for 12 hours; if the discharge current is 0.1 ampere, it can be used for 120 hours; if the discharge current is 0.5 ampere, it can be used for 24 hours; and so on
The battery also has another indicator, which is the rated working current Generally, do not exceed the rated working current when using, as the battery has a longer lifespan. Otherwise, the lifespan will be shorter Easy to peel off the inner plates due to excessive current
To connect a 300W lamp, the discharge current of the battery is required to be: I=P/U=300/12=25 amperes If it does not exceed the rated current of the battery Can be used; If it exceeds, or even exceeds a lot, it cannot be used
If it can be used The approximate usable time is: 12 ampere hours/25 ampere hours=0.48 hours Considering that the inverter itself, battery itself, and circuit have losses, it is shorter than 0.48 hours
1. MAh "is a unit of battery capacity, known in Chinese as milliampere hour (for the convenience of measuring large capacity batteries such as lead-acid batteries," Ah "is generally used, and the Chinese name is ampere hour).
1mAh=0.001 ampere * 3600 seconds=3.6 ampere seconds=3.6 coulombs
2. Coulomb is a unit of electricity, not a basic unit of the International System of Units, but a special unit of the International System of Units. 1 coulomb equals 1 ampere second.
The amount of electricity transported within 1 second with a current of 1A, i.e. 1C=1A · s.
3. Power calculation formula: P=UI. The unit of P is watts W; in a pure resistance circuit, according to Ohm's law, U=IR can be substituted into P=UI to obtain: P=I * IR=(U * U)/R
（1）、 The most direct algorithm:
1. First, obtain the current of the electrical equipment
2. The usable duration is obtained by dividing the battery capacity by the current of the electrical device
For example:
A 3000mAH battery with a rated voltage of 5V supplies power to an electrical device with a power consumption of 2.5W and a voltage of 5V. Its theoretical usage duration is:
I=P/U=>2.5w/5v=>0.5A=>500MA
3000mAh, 3000MA current can discharge for one hour,
3000/500=6 hours
（2）、 Using the Coulomb algorithm for charge quantity
C=IS=>3A * 3600s=>10800c Coulomb (charge)
10800c * 5v=54000w electrical energy
54000w/2.5w=21600/3600s=6h
