Product description
Lithium Battery Expansion Board for Cellphone Raspberry Pi 3 Model B Pi 2B B+

Feature:
Battery capacity: 3800mAH Maximum
output current: 1.8A
Output voltage: 5.1V ± 0.1V
Double USB output
Standard charging current / voltage: 1.0A/5.0V
It can last about 9 hours if only pi 3.
The Lithium battery expansion board can be also used on cellphone.

Description:
The working PMU (Power Manage Unit)can be only worked for charging mode or step-up mode at the same time.
If the USB-A interface without any external load (like Pi), with 5V input voltage of MicroUSB, then the PMU enter charging mode. The PMU will integrate a current-limiting resistor with the external voltage, 5V voltage for Lithium battery, around 4.6V-4.7V voltage for USB-A interface.(The "ON" LED lights )
The PMU would enter step-up mode without external 5V voltage. Under this circumstance, turn on the switch, USB-A interface can output maxmum 5V voltage, two USB-A interface can maxmum output 1.8A current. The PMU itself has current-limiting protection. it will be short circuit when over 1.9A current.

Note:
You can charging this battery even if the switch is turn off.
Raspberry Pi main board is not included!!!

Package Including
1 * V1.0 Lithium Battery Expansion Board