If the traditional Ni battery is charged for too long, the liquid inside would crystallize. In the way, to maximize the performance, the full charge and discharge are required. However, for the 2 cell Lipo battery, we can charge it whenever we are convenient.
It is a false about the lifespan of lipo battery that we should replace the lipo battery after charged for 300-500 times.
Instead, the factor influenced the lifespan is the charging cycle, and the times of charging will not directly influence the lifespan.
A charging cycle refers to the period from full power to the completely empty power and then fully charged. That does not mean charging for one time, as the following picture shows.
According to the picture, the battery is charged for 20% after the first time 40%. Then, after consumed some power, it is charged by 30% and 20% separately. In the half of this 20% (at the time of 10%), a charging cycle has been finished. And then, the next cycle begins.
For example, the first day, we charge the battery after consumed half of the power, and the second day, we repeat that process. This is just one charging cycle rather than two. Therefore, a cycle may be finished by several times of charging. Every single charging cycle will reduce the power slightly. However, a superior battery can maintain 80% power after many charging cycles. That is why some lipo battery can use normally after two or three years. Certainly, it is also needed that we replace the lipo battery if the lifespan has ended.
The lifespan of lipo battery is commonly 300-500 charging cycle. We set the Q as the power provided by one-time fully discharging. Ignoring the reduction of every charging cycle, the lipo battery can power 300Q-500Q through its lifespan. Accordingly, if we charge the battery after consuming ? power, the battery could be charged for 600-1000 times. (if we charge the battery after consuming 1/3 power, the battery could be charged for 900-1500 times.) we cannot tell the exact number of charging times if we charge randomly. In a word, the total power 300Q-500Q is constant. Therefore, the lifespan is related to the total charging power rather than the charging times. Besides, the difference between the influence of deep charging and discharging and the influence of light charging and discharging to lipo's lifespan is similar.
In fact, light charging and light discharging benefit more to the RC lipo battery. Only when the lipo battery is calibrated by the product has the need to charge and discharge battery deeply. Therefore, we can use the lipo battery for convenience and do not have to concern about the lifespan.
If the lipo battery is used above the regulated temperature (over 35 degree centigrade), the power will continuously decrease, which means the flight time would not be so long. If charged under the high temperature, the battery would be further damaged. It is unavoidable that storing under the high temperature will hurt the battery's quality.
If using below the 4 degree centigrade, you would also find the flight time of the battery has been reduced, and even some original lipo batteries of mobile phones cannot be charged. But, this situation is just temporary. Differ from using in the high temperature, once the temperature gets higher and the molecules inside the battery are heated, the battery would recover to the normal energy.
To maximize the performance of lipo battery, we should use it more often and make the electron flow. If we cannot use the lipo battery frequently, please remember to make a charging cycle and calibrate it (charge and discharge deeply) every month.