Lithium battery standard 3.7V or 4.2V is the same. It’s just that the manufacturer’s label is different. 3.7V refers to the platform voltage (ie typical voltage) discharged during battery use, while 4.2V refers to the voltage when the battery is fully charged. Common rechargeable 18650 lithium batteries, the voltage is standard 3.6 or 3.7v, when fully charged is 4.2v, this has little to do with the power (capacity), the mainstream capacity of 18650 batteries from 1800mAh to 2600mAh, (18650 power battery capacity Mostly 2200~2600mAh), the mainstream capacity even has standard 3500 or 4000mAh or more.

It is generally believed that if the no-load voltage of the lithium battery is lower than 3.0V, it is considered to be exhausted (the specific value depends on the threshold of the battery protection board, such as as low as 2.8V and 3.2V). Most lithium batteries cannot be discharged with no-load voltage below 3.2V, otherwise excessive discharge will damage the battery (generally, lithium batteries on the market are basically used with a protective board, so over-discharge will also cause the protection board to fail to detect To the battery, thus unable to charge the battery). 4.2V is the maximum limit voltage for battery charging. It is generally considered that the battery is fully charged when the no-load voltage of the lithium battery is charged to 4.2V. During the battery charging process, the battery voltage gradually rises from 3.7V to 4.2V, and the lithium battery cannot be charged. Charge the no-load voltage above 4.2V, otherwise it will damage the battery. This is the special feature of lithium batteries.