This module functions in the same manner as other charge modules, but has some added features:
Small size leaves more room in your build
The board measures only 1.22 x 0.57 inches (31 x 14.4mm)
Accepts 5v input for charging a lithium battery
It correctly charges a 3.7v lithium/lipo battery. Includes the standard battery management, such as charge/discharge control and short circuit protection.
The board includes charge indication connections if you want to add LEDs to your project. The RED LED pin connects to GND when the battery is charging, and the GREEN LED connects to GND when the battery is fully charged.
High-efficiency step-up converter
The 3.7v battery voltage is boosted to 5.2v for your project. This version allows for up to 1 ampere (maybe a little more) to power your project. This is plenty for my PSPi project, and should be enough for most Pi Zero projects. A Raspberry Pi 3 and LCD might push the limits of this board.
The board also has EN connections. These two connections are used to switch the 5.2v boosting on, and must be connected together. This means that a very small switch can be used to connect these pins together (only 16 microamps will flow through the switch). If this feature isn’t needed, then just connect the EN pins together.
This 1 amp version should be sufficient for most projects, but a higher-amperage version is in the works for those that need it.