It is a TP5000 battery charging module with support for lithium ion and lithium phosphate batteries and works with 4.2V and 3.6V batteries.The default charging current on this module is 1A but it is adjustable by changing the value of the current shunt sense resistor. It has over-current, over-discharge and over-current protection. The RED led indicates that the battery is charging and the green indicates that the battery is fully charged. The TP5000 Battery Charging Module has an input voltage range of DC 4.5V - 9V (the recommended input voltage should not exceed 7V). The default output voltage is 4.2V. The default output current is 1A. This module can also charge the lithium phosphate battery. To charge, the lithium-ion phosphate battery, you need to connect the solder pads with the F label. The output current is variable by soldering an additional resistor on the empty pad just below the SANYA label, under the R100 resistor. The TP5000 battery charging module has an integrated switching regulator, which reduces the heat produced compared to linear regulators. It also has a hollow pad on the underside to dissipate the heat, the user can fix the heatsink there, in case the output current needed is more than 1A. TP5000 battery charging module can work as a LIfePO4 charger and also charge the Li-ion battery.Features Input voltage range: DC 4.5V - 9V (Recommended input voltage should not exceed 7V) Output voltage: 4 , 2V / 3.6V (changeable) Default output voltage: 4.2V (for lithium ion battery) Can charge lithium ion battery (4.2V) and lithium phosphate battery ( 3.6V) Output current: 1A (default, changeable) LED indicator: RED indicates charging is ON, GREEN indicates charging is completed F Soldering pad connected: 3 lithium phosphate battery charging mode, 6 VF Soldering pad not connected: 4.2V Li-ion battery charging mode Adjustable output current: Default current: 1A (0.1ohm R100 resistor soldered under SANYA label) Output current: 1.5 A (soldering resistance 0.2 ohm below the resistance R100 s eight the SANYA label) Output current: 2A (0.1 ohm solder resistor under the R100 resistor under the SANYA label) Set the output current: 0.5 A (remove the R100 resistor under SANYA, instead solder the 0.2 Ohm resistor there) Additional heat sink required when the output current is more than 1A