For deployments using sample rates below 48kHz, then slower cards such as Class 10 or UHS Speed Class 1 (U1) cards, will likely work well. Make sure that you test them prior to deployment.
SD cards typically come formatted in one of two systems. Cards that are 32GB or less in size are normally supplied formatted using the MS-DOS (FAT32) system. Cards greater than 32GB are typically supplied formatted using the exFAT system.
From AudioMoth firmware version 1.2.2 onwards both FAT32 and exFAT file formats are fully supported. However, if you are using an earlier version of the AudioMoth firmware ensure that your SD card is reformatted as a MS-DOS (FAT32) card prior to use, or reflash your AudioMoth to use the newer firmware (see instructions here).
SD Cards
SD cards vary in their maximum write speed and also in their energy consumption. For most deployments we recommend using 32GB Sandisk Extreme UHS Speed Class 3 (U3) microSDHC cards. These work at all sample rates and have the lowest general energy consumption. The energy calculations presented in the AudioMoth Configuration App are based on the use of this card.
For deployments where larger cards are required we recommend both the 64GB Sandisk Extreme UHS Speed Class 3 (U3) microSDXC card or the 64GB AData Premier Pro UHS Speed Class 3 (U3) microSDXC card.
Other UHS Speed Class 3 will likely work but may consume more energy. The table below shows a comparison on the typical recording current for a number of cards. Note that there can be significant variation between cards.