I. Weight
In terms of the voltage of each cell, NiMH and NiCd are both 1.2V, while Li-ion battery is 3.6V, and the voltage of Li-ion battery is 3 times of the other two. And the weight of the same type of battery is almost equal between Li-ion and NiCd, but NiMH is heavier. It can be seen that the weight of each battery itself is different, but the high voltage of 3.6V of Li-ion battery can reduce the number of individual battery combinations by one-third in the case of the same voltage output and reduce the weight and volume of the formed battery.
II. Memory effect
NiMH batteries have the same memory effect as NiCd batteries. Therefore, regular discharge management is also necessary. This regular discharge management is handled in a vague state, and even some of them are discharged with incorrect knowledge (each discharge or discharge after several times of use varies from company to company) This tedious discharge management cannot be avoided when using NiMH batteries. Relatively speaking, lithium batteries are very convenient and easy to use because they have no memory effect at all. It does not need to pay attention to the residual voltage and can be charged directly, so the charging time can be naturally shortened.
III. Self-discharge rate
The self-discharge rate of NiCad battery is 15-30% (month). The self-discharge rate of NiMH battery is 25~35% (month), and that of Li-ion battery is 2~5% (month). The self-discharge rate of the above NiMH battery is the largest, and the special feature of Li-ion battery is extremely low compared with the other two types of batteries.
IV. Charging method
NiMH and Li-ion batteries cannot withstand overcharging. Therefore, NiMH batteries are best charged in a constant current charging PICK+CUT+control mode when the charging voltage reaches the maximum, stop charging. For Li-ion battery, it is best to use constant current and voltage charging method, if the NiCad battery is charged by the charger-DV control method for NiMH and Li-ion batteries.
