Lithium battery related knowledge

Battery life
I believe most consumers have heard that the lifespan of a lithium battery is "500 times", with 500 charges and discharges. Beyond this number, the battery will "die". Many friends, in order to extend its lifespan, charge it every time the battery is completely discharged, but this does not extend the lifespan of the lithium battery. The lifetime of a lithium battery is "500 times", which refers not to the number of charges, but to a cycle of charging and discharging.
A charging cycle means the process of charging the battery from full to empty, and then from empty to full. This is not equivalent to charging once. For example, a lithium battery uses only half its power on the first day, and then fully charges it. "If this is still the case the next day, that is, if you charge it half way through, and charge it twice in total, it can only be counted as one charging cycle, not two.". Therefore, it may usually take several charges to complete a cycle. Each time a charging cycle is completed, the battery capacity decreases by a bit. However, this reduction in power consumption is very small. After charging high-quality batteries for multiple cycles, they still retain 80% of their original capacity. Many lithium powered products continue to be used as usual after two or three years. Of course, lithium batteries still need to be replaced at the end of their lifespan.
The so-called 500 times refers to the number of times the manufacturer can charge at a constant discharge depth (such as 80%) of about 625 times, reaching 500 charging cycles.
(80% * 625=500) (ignoring factors such as reduced lithium battery capacity)
Due to various impacts of real life, especially the non constant depth of discharge during charging, "500 charging cycles" can only be used as a reference battery life.