Characteristics
Standard dimension of the Raspberry Pi hat, and is compatible with all expansion boards.
The cascaded design saves space while feeding raspberry pi and expansion plates without affecting the expansion of GPIO.
Support up to 2A fast charging technology, can quickly charge the battery.
You can charge and supply power to raspberry pi at the same time.
With 4 LED power indicator;
Provides a beginner example code to demonstrate how to demonstrate the battery capacity shows the current battery level in the current raspberry pi program, can detect the current battery, voltage, etc.
-Applicatoin Scene 1: You can program to control the automatic backup of the data at low power and safe closing.
-Applicatoin Scene 2: remind users to charge at low battery levels. Etc)
Removable battery, the user can choose a larger capacity lithium battery pack (note: the voltage should have 3.7V).
With safety protection circuit to avoid overload and discharge.
It retains the raspberry GPIO interface, you can still use all kinds of expansion plate;
It's Mini UPS power supply; maximum output of 5 V / 1.5A, and maximum input of 5 V / 2A.
[Two algorithms to obtain the capacity of the battery]
Stress estimation algorithm:
Obtain the voltage, then estimate the current capacity of the battery by the following rules.
Load
LED VBAT (battery voltage)
1 to 2 3,622
2 to 3 3,832
3 to 4 4,043
Full
4.182
Note:
The USP hat will provide power to Raspberr pi through GPIO pin;
Do not connectThemicro USB to rasberrry pi; please connect the micro USB to the UPS hat board;
Specification connector is: 2-pin PH 2.0 connector

Packing list:
1 x Raises the hat extension plate for Raspberry Pi 3 (does not include Raspberry Pi 3 Model B)
1X 3.7 V 2500mAh lithium battery (Optional)

Instructions
The UPS expansion board has a specific request on the size of the lithium board. The thickness of the lithium battery should be less than 9mm.
[One USB charging cable to two Micro USB
If you want your Raspberry Pi to start automatically when you have an external power supply or battery, instead of manually changing the power. You can use this USB to 2 Micro USB cable, USB connect charger, a Micro USB connect Raspberry Pi, another Micro USB connect the UPS hat. so as long as there is an external power supply or battery, Raspberry Pi can work properly. Unless the battery is low and the external power is lost.
This cale can also connect to the adapter to power the Raspberry Pi motherboard.
Note: the switch is disabled when using USB to Dual Micro USB charging cable; The raspberry pi will start automatically when the power returns.