This tiny module is perfect for charging single cell 3.7V 1 Ah or higher LiPo cells such as 16550s that don't have their own protection circuit. 

Based around the TP4056 charger IC this module will offer 1A charge current then cut off when finished.

Using the module

• Connect mini USB cable for power, or 5V DC to pads marked IN+ and IN- on left-hand side of the module
  
• Connect cell to charge to BAT+/BAT- pads on right-hand side of module
  
• A load (something for the battery to power) can be connected to the BAT+/BAT- pads on the right-hand side
  
• Important! Disconnect load when charging
  
• The red LED indicates charging in progress, green LED indicates charging has finished.
  
• Never charge your battery at a rate greater than 1C.

Specifications

• Input voltage - 5V via MINI USB or solder pads on left-hand side of module
  
• Full charge voltage - 4.2V
  
• Charging current - 1A by default. However you can change this by changing the 1k2 resistor next to the "IN-" pad the bottom-left of the board. See the Rprog table on page three of the TP4056 data sheet for different values and matching charging currents

Documents

TP4056 Datasheet