How big is the charger for 18650 lithium battery 3.7V5000mAh?

18650 lithium battery 3.7V5000mAh what kind of charger is used? Hello dear, use a 5V charger with an output current of at least 5A. The volts of the charger are greater than the volts of the battery. 18650 volts are generally 3.2-3.6 volts. The charger uses 4 to 5 volts and the charging time is related. It can be connected in parallel to charge and discharge, and then the voltage will be balanced; if one battery is 3.6V and the other is 3.9V, the voltage difference is 0.3V, the internal resistance of the battery is 40mΩ+40mΩ=80mΩ, and the charging and discharging current is 0.3V÷80mΩ=3.75A. The instantaneous discharge current of 18650 lithium battery is 2C and the current is about 5A, and the charging current is 1C=2.5A, so the battery will not be damaged.