Now mobile phone batteries are all lithium batteries, and the lifespan of lithium batteries is generally 300-500 charging cycles. 

    Assuming that the power provided by a complete discharge is 1Q, if the reduction in power after each charging cycle is not considered, the lithium battery can provide or supplement 300Q-500Q of power in its life. From this we know that if you charge 1/2 each time, you can charge 600-1000 times; if you charge 1/3 each time, you can charge 900-1500 times. By analogy, if it is charged randomly, the number of times is variable. 

    In short, no matter how it is charged, the total power of 300Q-500Q is constant. Therefore, it can also be understood like this: the life of a lithium battery is related to the total charge capacity of the battery, and has nothing to do with the number of recharges. Deep discharge and deep charge and shallow discharge and shallow charge have little difference in the impact of lithium battery life.