The acronym "mAh" indicates the amount of energy stored by the smartphone battery. Here's what it means and why it's important
One of the data most emphasized by smartphone manufacturers is the battery capacity, expressed in "mAh". mAh means "milliAmpereOra", i.e. how many milliAmpere the battery can deliver in a unit of time, i.e. in one hour.
Because modern smartphones are almost like laptops and have considerable power consumption, it is clear that the more mAh a battery has, the more autonomy the smartphone will have. However, do not make the mistake of judging a smartphone only by the amount of mAh of the accumulator, otherwise then you risk buying the one with "more battery" without this translating into "more autonomy". The amount of energy of a battery and autonomy, in fact, go hand in hand only if other factors are equal. In other words: smartphone A could have a longer autonomy than smartphone B even if it has a battery with less mAh than the second one. How is this possible?
What affects the autonomy of a smartphone
For several years now, smartphone manufacturers do not allow to replace the battery: it is integrated in the device and cannot be changed. The choice of battery, therefore, is made on the basis of a main parameter: how long will be able to keep the device on, with an "average" use. Smartphone manufacturers, in practice, mount a battery with the minimum essential capacity to get the phone to the end of the evening. And they do the calculation easily, because they know exactly how much power their device consumes. A smartphone with a 6-inch screen, for example, will reasonably consume quite a bit more power than one with a 4-inch display. One with 8 GB of RAM will consume more than one with only 4 GB. A device with a high-frequency SoC will consume more than one with a low-frequency SoC, and so on.
The Optimization Factor
Then there's another thing to consider: software optimization. There are practically identical smartphones that should theoretically consume the same amount of power and have the same mAh of battery that, however, have very different battery life. This is due to the optimization of the operating system and UI done by the manufacturer, which can make a lot of difference and give us, at the end of the night, even 60-120 minutes of autonomy more. If a smartphone has a very heavy software, with many applications running in the background, it is logical that its hardware will work (and consume) more. The exact same device, on which runs lighter software, will consume less energy. That's why, after a software update, the battery of a smartphone can last significantly longer, or less, than in the past.