disconnected RTC

[fredrlw]

I use my RPi for research and don't allways have acces to the internet which is crucial, especially when my data logging requires time stamps. I will therefore use a RTC but i am wondering if it has to be connected to the RPi all the time, or could i just plug it in when i need it? (after the first configuration ofc).
I have a breadboard which i mount temporary sensors and modules on which is connected with a 40 pin breakout which i disconnect when i travel, so the RTC won't be connected at all time

[DougieLawson]

An RTC is designed to keep the system clock right when it's not connected.

When it is connected to the internet run sudo hwclock --systohc to resync the RTC to the ntp time (assuming you're running ntpd).

I've also got a script in /etc/cron.daily/adjhwc

Code: Select all

#!/bin/sh
/sbin/hwclock --adjust

which gets run at 06:25 local time every morning.