I have Arduino Uno with SD card shield. I'm planning to log a huge amount of data from various sensors - including accelerometers and 3D compass - to the SD card.

However, I have understood that Arduino, 64GB SD, FAT and large amount of data are not working too well.

Does Arduino work well with this amount of data on FAT? There's no need to read any data from SD on Arduino. If not, is there a better approach? Writing directly to SD without FAT?

This data logger will be on the environment where no computer or network connection is available. Performance is not an issue - around 8kB/s (over three months) is already enough.

2 Answers 2


I'm not sure where you have the impression it won't work. I haven't used 64GB cards, but have used 32GB cards and they work fine in terms of FAT32 and writing files.

As you have already worked out, reading or searching the file system can get very slow as size increases.

That said, I have found that larger capacity cards are more likely to have problems with the SPI interface being poor quality. Consumer devices do not use the SPI interface, and it seems that some manufacturers are willing to skimp on this side of it. The SPI interface can be buggy or unstable as a result. Genuine name-brand cards should work fine though.


You should consider using sdfatlib. This is currently supported version. Where an early version of this was the predecessor the IDE's stock SD library. SdFat better supports newer and larger SdCards, along with more features.


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.