However, the milliampere hour (mAh) only involves current and time, and the voltage is missing.
The speed at which electrical energy is consumed or output by the battery, generally expressed in W (watts), or kW (kilowatts). 1W is equal to the speed of the electrical appliance to do work at voltage 1V and current 1A, and it is also equivalent to the speed of 100V and 0.01A. When expressed as a battery, it is the speed of the output energy.
As long as the voltage and current product is the same, no matter how much the ratio of voltage to current size is, the speed of work, that is, the speed of energy consumption, that is, the power size, is the same, for example, 1V*1A=100V*0.01A=0.5V*2A=1W, 1 watt is also equal to 1 joule per second, 1W=1J/S, So the milliwatt, watt, or kilowatt is a unit of the magnitude of the speed at which work is done.
The total amount of electric energy consumed by electrical appliances in an hour is how many kilowatts, or the total amount of electric energy output in an hour of battery time is how many "degrees" we usually say, that is, the product of power and time. The units of current and time are mWh, Wh, or kWh. 1W=1V*1A*1h=1V*1000mA*1h=1000mW, corresponding conversion, 1kWh=1kW*1A*1h=1W*1000A*1h, etc., the product of the three is equal, the work done or the power output is equal.
For example, according to the above method, the capacity of the battery after series and parallel connection is 3.6v15000mah or 18V3000mAh, and the total capacity is 3.6 * 15000=18*3000=54000mAVh(milliwatt-hour)=54Wh(watt-hour). Battery series or parallel does not change the capacity used, just to get the right voltage or current, to meet the requirements of electrical appliances, which is in line with the basic principles of physics.
The problem comes, the battery capacity is marked mAh or Ah, but has nothing to do with voltage, whether the two batteries, mAh or Ah are the same, their ability to output energy must be the same?
Obviously not. For example, a car battery, 12V60Ah, and a lithium battery pack 3.6V60Ah, are all 60Ah, the ability to output energy, that is, the capacity, but very different. The former is 12*60/(3.6*60)=3.33 times of the latter, because the former voltage is 3.33 times of the latter.
Therefore, Wh or kWh is the accurate unit to identify the power supply capacity or load power consumption, mAh or Ah is not.
Obviously, after the battery is connected in series and parallel, the calculation of Wh or kWh is exactly the same as the calculation of the battery mAh or Ah above.
