DDFR0528 ONPOWER UPS hat for Raspberry PI v1.3 power on with no charger?

I would like to say that this is a very good device.
It has enabled me to build a portable Internet Radio with about 10 hours of autonomy.
It has performed faultlessly to specification and charges well and controls the power when the charger is disconnected.
I have also programmed the system to warn the user when battery level requires charging using the registers on the UPS board.
It is also programmed to shut down the system down in an orderly fashion before power is cut by the board.
I soldered another push button switch across the existing one on the board and brought it to the front panel.
This allows power on/off from the front panel.

If you are ever revising the board there are two things that I can suggest.
1. That power can be connected to the computer when no power is connected to the UPS board.
Currently the charger needs to be connected to power it up. After that the charger can be removed.

2. That a register can be written to allow a programmed shutdown in a number of seconds based on the value written.
This would allow a delay of 1-255 seconds before power is cut to the computer.
A value of 0 written could be used to cancel any shutdown.
This would would remove the need for a two stage shutdown, actioning shutdown of the system, and then cutting the power with the power switch.

I have also updated the program you supply for voltage and battery %. It now also prints the board version.

import smbus
ups_addr=0x10 #ups i2c address
bus=smbus.SMBus(1) #i2c-1
versionboard=bus.read_byte_data(ups_addr,0x02)
vcellH=bus.read_byte_data(ups_addr,0x03)
vcellL=bus.read_byte_data(ups_addr,0x04)
socH=bus.read_byte_data(ups_addr,0x05)
socL=bus.read_byte_data(ups_addr,0x06)

capacity=(((vcellH&0x0F)<<8)+vcellL)*1.25 #capacity
electricity=((socH<<8)+socL)*0.003906 #current electric quantity percentage
mainversionboard=(versionboard)>>4
subversionboard=versionboard&0x0F
print("board version=%d.%d"%(mainversionboard, subversionboard))
print("capacity=%dmV"%capacity)
print("electricity percentage=%.2f"%electricity)