Need help to handle data save at Power Failure Scenarios

Projects General Guidance
1

I am using Arduino Mega 2560 for my project. In my project, I have a need to persist the data of size of around 3 KB each time either when the machine is switched off or at power failures.

Please help me clear the below 2 questions related to this.

  1. Since I need to save the data a minimum of 50 times a day, I am thinking to save the data not in EEPROM as it has write limits, rather I am thinking to save the data on the SD card. SD card is already part of my project for other functionalities, so I am planning to make use of it even for this purpose. Please let me know if this is a good approach?

  2. I am really unsure of designing a circuit which handles power failure detection mechanism.
    I have been going through some circuit's schematics online where resistors and capacitors are used to save data at power failure, but I am unable to decide if it is the best approach. Since I am a newbie in Electronics, can you please suggest the reliable mechanism to save data, and any online resources to read more on this would be helpful.

Thank you very much in advance.

P.S. My project circuit has access to 15V DC power supply.

2

an alternative to SD card is FRAM

3

If I was concerned about power failure I would power the Arduino from a battery that is continuously trickle charged from the mains. If the mains power fails the Arduino will continue. If you wish to detect that the mains power has failed then add a diode to prevent the battery from back-feeding to the mains power supply and use the Arduino to monitor the charge voltage upstream of the diode.

...R