18650 battery 1800mah.Four charging methods for 18650 lithium battery

Someone has done experiments specifically and found that the total capacity of a fully charged 18650 lithium battery will decrease by 20% after being left alone for one year; while the total capacity of a lithium battery that is charged to 40% will only decrease by 5% after being left alone for one year. Lithium batteries that have not been used for a long time can be charged to about 50% and stored at low temperatures (such as refrigerator freezers).

The battery itself will have a certain amount of self-leakage, and the protective board will also consume microampere power. Therefore, during long-term storage, the voltage must be measured regularly and recharged.

1. Constant current charging: This method is still derived from the previous and previous circuits, but it limits the very high charging current. Constant current and constant voltage is actually "current limiting and voltage limiting". This kind of circuit is more popular, such as Nanfu, He Xinyu and others do not completely cut off the battery after full charging, and instead use trickle and float charging - it is now believed that long-term low-current charging is one of the causes of battery bloating.

2. High-voltage charging: This charging method does not have a special control circuit. It directly uses a 5V power supply (or a diode in series to reduce the voltage) to charge the battery with a protective plate, completely relying on the high-voltage limit of the protective plate. The characteristic is that the current is very high at the beginning, then gradually decreases, and floats at any time.


3. Intelligent charging: This is now considered an ideal charging management method. It follows the charging algorithm mentioned at the beginning of this section and is integrated into a small chip IC. The peripheral circuit is simple, stable and reliable, such as TP4054/4055/4056. /4057, TP4002/5000, MAX1879, etc. The main feature of this chip is that it will monitor the voltage and current at the same time when judging whether it is full, and stop charging, or the charging current is less than (usually about 50mA); it will completely cut off after full, there is no trickle and float charge, but it will be monitored at any time If the battery voltage drops to a certain value, charging will start.

4. Constant voltage charging: This method is similar to the previous one. Constant voltage is actually "voltage limiting". It sets a relatively accurate high voltage and then charges it to that voltage. It will not stop until it is reached. People in the world call it "silly charging". , if this kind of charger makes the cut-off voltage very accurate, it will be safer if it is too low. If it is too high, you have to rely on the protection board. As for the bare battery, you will be lucky. Commonly seen in today’s all-in-one mobile phone chargers and direct flashlight chargers, this charger costs less than one yuan and is made entirely of inferior parts. The retail price on Taobao ranges from high to high, and it’s hard to say how long it will last.