- Sun Jun 17, 2018 12:52 pm
If there is a good backup battery on the DS1307 module, it will keep time when the power is off. Post a link to the module you have.
The DS1307 is a poor timekeeper and will typically gain or lose a minute or two every day. The DS3231 is much better.
It is tricky to set any RTC to the correct time, because data transfer will take some time to execute. With some trial and error, you can get the RTC time to be current within a few seconds.