Forum member @Grey posted about the use of a rtc-ds3231.
viewtopic.php?p=27337#p27337
https://www.banggood.com/High-Precision ... mds=search
I ordered two of them for 10€ plus postage.
The 'How-To' list is very short using EasyOS for the Raspberry pi.
Add this to the raspberry pi config.txt file:
# Adds support for a number of i2c real time clock devices
dtoverlay=i2c-rtc,ds3231
Use the console to read the rtc hardware time:
/sbin/hwclock -r
Use the console to make the rtc time your system time:
/sbin/hwclock -s --localtime (This is help full while running on 'Daylight Saving Time'/DST)
This small executable script at /root/Startup named piRTC will copy the rtc time to your system.
#!/bin/sh
/sbin/hwclock -s --localtime
/sbin/hwclock --help (This will show you a list of all available tools.)
I'm using this rtc while my pi is off line.
Have Fun!
- pi4-rtc-2.jpg (110.98 KiB) Viewed 549 times
Rem: I have added '--localtime' as well as /sbin for it's location.