Taking a battery that reaches twelve volts but 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.
20ah means that when the battery output current is 20 amps, it can be used for 1 hour, and it can also be understood that when the battery output current is 2 amps, it can be used for 10 hours. That is, the product of current and time is 20.
When the device requires a high-power battery of 20ah to drive, this indicates that the device has a large working current, and a small-capacity battery may not be able to withstand this large current. If the small-capacity battery can withstand the device drive current, it can drive. Just like your more than a dozen AAA batteries connected in series to drive an electric bicycle, it cannot be driven.
This is the capacity of the battery, not the power, that is, the time that an electrical appliance of a certain power can work. The length of the working time depends on the power of the electrical appliance.
In addition to 100Ah, the battery also needs to know the magnitude of the voltage. This battery can work for 1 hour at 100 amps. The specific power depends on the battery voltage. For example, a 12V battery, if the working current is 100 amps, can make 1200 watts of electrical appliances work for one hour, and if 10 amps are used, it can work for 10 hours. It depends on how much current is used to determine the working time.
The battery does not talk about power, but talks about "milliamps · hours", that is, how many milliamp hours can be discharged, which is its electrical energy capacity. The voltage of the new ordinary AA battery is 1.5v, the internal resistance is about 1 ohm, and the voltage will decrease when discharged. If the discharge current reaches 500 mA, 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 life. Continuous discharge life is shorter.
The unit of power is Watt (W), which is P = UI, 1W = 1V.A (one watt is equal to one volt.A)
Battery capacity mA.h (mAh)
Obviously these two parts are different.
Further looking for relationships:
Joules of electric power (J)
By W = Pt
It can be seen: 1J = 1W.s = 1V.A.s (one joule equals one volt-ampere second)
If the battery voltage is known, multiply the battery capacity by the voltage and see what you get: the unit is V.mA.h
In fact, it is essentially the same as the unit of electrical energy.
1V.mA.h = 1V * 10 ^ -3A * 3600s = 3.6V.A.s = 3.6J
The battery is an energy storage element. When there is no power, it has a rated capacity. The unit is wh. Watt-hours. It can be obtained by multiplying the voltage by the capacity, such as red rice.
"12V12AH battery" does not mean that its power is 12 * 12 = 144 watts!
"12V12AH battery" refers to the capacity of the battery. That is, the rated operating voltage of the battery is 12 volts, if the discharge current is 1 amp, it can be used for 12 hours; if the discharge current is 0.1 amp, it can be used for 120 hours; if the discharge current is 0.5 amp, it can be used for 24 hours; etc.
There is another indicator of the battery, which is the rated operating current. Generally, do not exceed the rated operating current, the battery has a long service life, otherwise the life is short. [It is easy to peel off the inner plate due to the excessive current].
"Connecting a 300W lamp" requires the battery's discharge current to be: I = P / U = 300/12 = 25 amps. If it does not exceed the rated current of the battery, it can be used; if it exceeds, or even exceeds, it cannot be used .
If it can be used, it can be used for about 12 hours / 25 hours = 0.48 hours. [Considering that the inverter itself and the battery itself and the line are lossy, it is shorter than 0.48 hours.
1. "mAh" is a unit of battery capacity. The Chinese name is milliamp hours (when measuring large-capacity batteries such as lead storage batteries, for convenience, it is generally expressed as "Ah", and the Chinese name is ampere-hour).
1mAh = 0.001 Amp * 3600 seconds = 3.6 Amp seconds = 3.6 Coulomb
2. Coulomb is a unit of electricity. Coulomb is not the basic unit of the International System of Units, but the derived unit of the International System of Units. 1 coulomb = 1 amp · s.
The amount of electricity transported by a 1A current in 1s, that is, 1C = 1A · s.
3. Power electric power calculation formula: P = UI. The unit of P is Watt W; in a purely resistive circuit, according to Ohm's law, substituting P = UI into P = UI can also get: P = I * IR = (U * U) / R
First, the most direct algorithm:
1. Get the current of the electrical equipment first
2. Divide the battery capacity by the current of the electric equipment. The result is the usable time.