The capacity units in the lithium battery label are mAh and Wh.
Nowadays, most mobile devices and cameras use lithium battery packs, and most consumers do not understand the capacity labels on these battery labels, such as mAh and Wh, which represent nothing. Actually, learning to understand these signs is very simple and practical.
In fact, if these two batteries are also mobile phone batteries, their capacity can still be compared in mAh. But if they are not the same type of product, comparing them directly may be wrong. Aren't they all lithium batteries? Aren't they all the same? Why can't we compare? Although they are both lithium batteries, the voltage of these two batteries is actually different. Due to voltage reasons, there is no comparability simply based on the size of the mAh number.
Simply put, the physical meaning of battery capacity refers to how much charge a battery can hold or release. We often use Ah (ampere hour) or mAh (milliampere hour) to represent it.
According to the definition formula of current: I=Q/t, it can be known that Q=It. The unit of current I is mA (milliampere hour), and t represents time in hours (hour). Therefore, our battery capacity unit is mAh.
That is to say, if a battery has a capacity of 1000mAh and operates at a current of 100mA, it can theoretically provide power for 10 hours of use.
However, from the formula, we can see that Q=It does not involve voltage, so this unit can only indicate how much Coulomb charge can be accommodated inside the battery. But it cannot explain how much work this battery can do or what the maximum power that the battery can provide. The working voltage of different types of products is different. Therefore, we often see a number in Wh next to mAh. The work that a battery can do is W=UIt=UQ, and the unit of voltage U * current I is W (watts). Therefore, W in the battery is expressed as Wh, which represents how much work the battery can do.
Wh is a quantity directly proportional to voltage, current, and time. And mAh is usually used as an indicator for battery charging and discharging, which is directly proportional to the charging (discharging) current and time of the battery. To make it comparable or convertible to Wh, the voltage of the battery must also be known. Simply put, Wh=mAh/1000 * voltage.
And the voltage of the 6600mAh battery mentioned earlier is 14.4V, 14.4 * 6600=95.04Wh, so the total work it can do when released is 6.6 * 14.4 * 3600=342144 joules of work.
And the voltage of a typical mobile phone is 3.7, so the theoretical work that the 5200mAh power bank can do is 3.7 * 5200=19.24WH, and 3.7 * 5.2 * 3600=69264 joules of work.
