This UPS has an onboard RTC module, coulomb counter, USB-C connector, and charging status LED indicators.

You can obtain the UPS battery voltage and current information through I2C and the UPS can use most of the 18650 standard batteries. In addition, the power display provided on the circuit board is also very user-friendly. The illuminated LED light can quickly show the remaining power and supports discharging while charging. You can directly connect to the external power supply for charging. At the same time, the Raspberry Pi will not be turned off.

Features:

• RTC Independent Clock
• Current and Voltage Reading
• One-Click Start – Power up Sequence
• USB-C interface and USB Output Power Supply
• Programmable Reading of Battery Voltage in OS
• Charging Status LED indicators
• 5V / 4A Output

Note: Please install the battery first, then connect the UPS to the Raspberry Pi.
Reverse battery insertion WILL damage your Pi.

Documentation:

• https://wiki.52pi.com/index.php/UPS_(With_RTC_%26_Coulometer)_For_Raspberry_Pi_SKU:_EP-0118
• https://github.com/geeekpi/upsv3