The protection board is used for 5 series lithium-ion batteries, mainly used in power tools It uses an IC dedicated to 5S lithium batteries as a processor to detect the real-time voltage, charge and discharge current and ambient temperature of each battery Stable charge and discharge protection functions such as overcharge protection, over-discharge protection and short-circuit protection Low power consumption, working current of about 25uA, static current of about 6uA Choosing a suitable protection board and using it appropriately is crucial to extend the battery life Charge Voltage: 19/21V Single Cell Charge Voltage: 3.8/4.25V Continuous Discharge Current:8-20A Overcharge Protection Delay:1S Note: This protection board is used to protect the battery from overcharging and over-discharging. It cannot replace the charger. You still need a special charger for lithium batteries when charging! After connecting the wires, it needs to be first before there be output Colour:Green Material:PCB Package Contents: 2 x Battery Charging Protection Board Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.