Some 18650 lithium batteries increase capacity in parallel, such as 20,000mAh to move the power supply, and some are composed of eight 2600mah batteries or six 3400mah 18650 batteries. The capacity of 3.7V is increased in parallel, and then the voltage is improved through series. Two series are 3.72=7.4V, and three are 12.6V, and so on.

     Usually, electric vehicles and notebook batteries need to increase the battery voltage to 12V or 36V 48v 72V through multi-battery series. At this time, if the capacity or quality of the battery varies, there is always one that consumes much first in the utilization process, just like the short board principle of the barrel. A battery or the parallel group of batteries affects the total battery voltage and capacity of all battery packs. For example, laptops are 2 and 3 strings, forming a 10.8V to 12.6V battery. A set of two parallel batteries consumes first, which will cause all the batteries and capacity to fall. Specifically, the battery is short standby time, the charging speed is fast, and the power consumption is fast. The same is true for equipment such as electric vehicles.

     At this time, it is necessary to change the battery pack to avoid the barrel effect (short board principle - the barrel can hold water depends on the short board of the barrel). In this way, it is possible to make balanced use of the battery and extend its useful life.

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