1. High-voltage charging: This charging method does not have a special control circuit, and directly uses the 5V power head to charge the battery with the protection board, completely depending on the high-voltage limit of the protection board. The characteristic is that the current is very large at the beginning, and then gradually decreases, and it can be floated at any time; most of the things that will explode are this kind, which is common in low-end plug-in cards, MP3, etc., high-end ones can’t be bought, I don’t know – I dare not say that such an expensive machine should There is such a thing as a charging circuit – there are many things that should be done, and more things that should be done but not done;
2. Constant voltage charging: This method is similar to the previous one. Constant voltage is actually a voltage limit. Set a relatively accurate maximum voltage, and then charge to that voltage. If it is less than 4.2V, it will never stop. If the cut-off voltage of this kind of charger is made very accurate, it will be safe if it is too low. If it is too high, you have to rely on the protection board. It is common in the current mobile phone universal charger and flashlight direct charger. This kind of charger costs less than one yuan and is made of inferior parts. The retail price on Taobao ranges from 2.00 to 15.00. It is hard to say how long it will last;
3. Constant current charging: This method is still derived from the previous circuit and the previous one, but it only limits the maximum charging current. Constant current and constant voltage are actually current limiting and voltage limiting. The son of a stupid charger is still a fool. This kind of circuit is more popular, such as Nanfu, Hexinyu, etc., it is not completely cut off after being fully charged, and it is changed to trickle floating charge-now it is believed that long-term low-current charging is one of the reasons for the flatulence of 18650 lithium batteries;
4. Intelligent charging: This is an ideal charging management method. It follows the charging algorithm mentioned at the beginning of this section and is integrated in a small chip IC. The peripheral circuit is simple, stable and reliable, such as TP4054/4055/4056 /4057, TP4002/5000, MAX1879, etc. The important feature of this chip is that it will monitor the voltage and current at the same time when judging whether it is full, stop charging at 4.2V, or stop charging if the charging current is less than 0.01C (usually about 50mA); it will be completely cut off after full, and there will be no trickle float charge , but monitor the voltage at any time, and start charging if the voltage of the 18650 lithium battery drops to a certain value.
When using lithium-ion batteries, it should be noted that the 18650 lithium battery will enter a dormant state after being placed for a period of time. At this time, the capacity is lower than the normal value, and the use time will also be shortened accordingly. But the lithium-ion battery is easy to activate, as long as it goes through 35 normal charge and discharge cycles, the battery can be activated and the normal capacity can be restored. Due to the characteristics of the lithium-ion battery itself, it has almost no memory effect. Therefore, the new lithium-ion battery in the user’s mobile phone does not need special methods and equipment during the activation process.
The activation of lithium-ion batteries does not require a special method, and lithium-ion batteries will be activated naturally during normal use. If you insist on using the popular first three 12-hour long charge activation methods, it will actually not work.
When the quality of the original charger’s own protection and control circuit is good, the protection of the 18650 lithium battery is still quite guaranteed. Charge according to the standard time and procedure, even for the first three times.
