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DC 4.2V 0.5A 3.5mm Flashlight balance Charger Adapter 3.7v 18650 16340 Battery torch lamp
Basic parameters:
Output voltage: 4.2V
Output current: 300-500 mA 
Connecting DC jack size: 3.5 round hole plug
Input voltage: 220-240V


Usage:
output 2 wires, green light for normal standby state charged, red light when charging, when charging the battery the voltage reaches about 4.16V, the red light turns to green . At this time, the charger does not completely stop charging, but continues to charge with a small current trickle. The maximum cut-off voltage is 4.21V. 
The charger is equipped with a full set of protection, so no short circuit will damage the charger.


The indicator status indicates:
The green light is standby (4.16V trickle state when charging), the
red light is charging!
Flashing green light means over voltage 4.21V
flashing red light means battery failure or short circuit


The input is 100V-240V, and the output is 4.2V 300-500mah, suitable for lithium polymer batteries with a capacity of 500mah-5000mah!
The charger has short-circuit, over-current and over-voltage, and short-circuit protection for reverse connection of positive and negative poles!