Deployed 19 AudioMoths units over 8 sites in the southern half of the lower pennisula of Michigan. AudioMoths were deployed the end of February, with batteries and memory cards changed out the end of July and all devices collected the middle of November.

Based on the configuration  they should of lasted ~150 days.

(Sample rate: 48 kHz; Med gain; Enable sleep/record cycle; 00:04:45 sleep duration; 15 sec recording duration; Enable LED; Enable battery level indicator; 24 hrs/7days recording period = Each day will produce 288 files, each 1440kB, totaling 415 MB; Daily energy consumption approx. 19 mAh).

AudioMoths stopped recording after ~30 days (btwn Feb. 24 and March 29) and after ~60 day (btwn July 22 and Sept. 24).

I was using Energizer Ultimate Lithium AA Batteries and Amazon Industrial Alkaline AA batteries with Amazon basics microSD XC1, 64 GB, V30, Class 10, U3, A2.

Batteries were a couple years old, but not expired and in good shape. MicroSD cards were one year old. All AudioMoths were new or only a year old.

Any thoughts on what happened? I am at a loss.

Didn't run out of storage space on the microSD cards (415 mb per day was a reasonable estimate for space used over the 30 and 60 days). Used the same type of batteries in a variety of different trail cameras at the same 8 sites and they lasted the expected duration (~150 days).