I just had a pretty simple question about the RTC Clock Modules, more specifically the DS3231 RTC. Once calibrated and running on my Arduino if I were to unplug it and plug it back in, will the time and everything reset and require another calibration, or will it work like a computer that, even when reset, retains the correct time and date. Thanks!

1 Answer 1


It depends if your module has a battery backup or not. A bare chip, by itself, will loose everything. That's why many breakout boards will have a small lithium cell on them to retain everything when the power is removed.

  • So it will be attatched to a breadboard and then attatched to the Arduino. If the main power supply to the Arduino, which is a external 5V battery source, you are saying it would be wise to also have another backup source just in case?
    – tyler a
    Commented Jul 18, 2016 at 15:02
  • Like I said, it depends on your module. If you are building it from components, then yes you should provide a battery backup - like it shows you in the datasheet.
    – Majenko
    Commented Jul 18, 2016 at 15:03
  • This is the module I will be using
    – tyler a
    Commented Jul 18, 2016 at 15:05
  • That is what you have? Do you know what that big round silver thing is in the picture?
    – Majenko
    Commented Jul 18, 2016 at 15:06
  • 1
    Brilliant. Sorry, long day. Thanks for the help.
    – tyler a
    Commented Jul 18, 2016 at 15:08

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