Stopped recording despite space on SD card and charge in batteries.
Hello,
Last year, I purchased 20 AudioMoths via GroupGets. I deployed them for 2 months at a site Feb - Apr 2025, each in the weatherproof cases. I configured them to record at a sample rate of 48 kHz and 16-bit depth, with bursts of 1 min recording periods, then 4 mins of sleep 24/7. We changed the batteries mid-way through, using the chime app to reset date/time, and upon review of the devices, the batteries lasted for 3 weeks (AA Ni-MH 1.2V 2400mAh). 256GB SanDisk Ultra SD cards were used. All went smoothly, and recordings were as expected.
This year, I have come to repeat my survey, following the same protocols as the previous year (other than accidentally using 4 min burst of recording with 1 minute of sleep!). Upon reviewing the SD cards, not a single device has recorded as expected. Some have no recordings at all, whilst others have recorded for 2 or 3 days before and after the batteries were changed. Others recorded for a few days when first deployed, then for 10+ days after batteries changed. No two devices have behaved exactly the same.
What is strange to me is that for many of the devices, there is still plenty of space on the SD cards and charge remaining in the batteries.
What has gone wrong?
Hi Abby, Can you use the 'Summarise AudioMoth Files' option under the 'Process' menu in the Config App to generate a summary of the contents of one of the SD card. The 256GB SanDisk Ultra SD card use about 3-4 times the energy of the 32GB SanDisk Extreme card that the Config App uses for the energy calculation so you may just be running the batteries down much faster with the four minute recordings.
Were the SD cards reformatted before use, or were the files just deleted from them? If the latter, that may be the reason as AudioMoth cannot recover the space in the file allocation table in realtime.
Alex