repeated SD card failures after extensive recordings

Dear AudioMoth community,

I am currently on fieldwork and I am using the AudioMoths for two different setups:

• A long-term experiment lasting 3 days, with around 18 hours of recordings per day. This is repeated 3 times (so 9 days in total). All 16 AudioMoths are used. (finished experiment)

• Daily experiments with 4hrs of recordings in the evening and 5 hrs in the evening. 14 AudioMoths were placed in cones to record one individual animal. (ongoing experiment)

For both these setups I require synchronised recordings, hence all AudioMoths have been flashed with the GPS Sync firmware. I have attached the SETTINGS.txt files for both setups.

I am currently doing the daily experiments and more and more AudioMoths keep showing up with SD-card failures or other forms of data loss. So far, 9/16 AudioMoths needed a replacement SD card. Of the AudioMoths with this issue, battery levels were generally good (>4.7 V). All AudioMoths are equipped with Energizer Ultimate Lithium batteries and Sandisk Extreme microSD card 64 GB. Temperatures inside the cone can get somewhat hot (< 34 C) as it is summer.

Does anyone have suggestions on what could be the problem? I am happy to replace the SD cards, but I'd like to know the root cause. My ideas of potential causes are:

• My recording schedule during the long-term experiment is too extensive. The AudioMoth writes out files every 4-5 hours. Could this cause a strain on the SD-cards?

• The AudioMoth get too hot inside the cones, which may harm the SD card or other processes.

Any help is appreciated.