I am testing some methods to extend the battery life of the audiomoth. I have successfully powered the audiomoth using a battery pack that holds 8 AAs instead of 3 AAs, but the extra batteries did not extend the life of the audiomoth. I ran two tests - first I used the standard 3 AA battery pack that comes with the audiomoth and let it record continuously until the batteries ran out. Then I switched to the 8 AA battery pack and repeated the test with identical settings. In both cases the audiomoth ran for 8 days before the files started being clipped (after 8 days the files lengths got progressively shorter and listed "Recording cancelled before completion due to low battery voltage" in the comments section). Strangely, with the 8 AA battery pack the unit stayed above 4.9V even after it started clipping files "due to low battery voltage" I had expected the extra batteries would let the audiomoth run 2-3 times longer. I'm not sure why that wasn't the case.

My audiomoth stops recording when the battery goes below 4.0V. I configured my audiomoth to record for 30 minutes at a stretch with 0 seconds rest between. I am using alkaline batteries and an external battery pack connected via USB. The setup recorded perfectly for 2 days, but after that it started making empty sound files. I thought maybe the issue was that I hadn't left enough time between recordings. I read that sometimes when the battery is low it takes longer for the audiomoth to write a file and will skip scheduled recordings if there isn't enough of a gap between them. I reprogrammed the audiomoth to leave 30 seconds between recordings but it didn't fix the issue. I also noticed that the audiomoth is only using charge from the 3 AA batteries and not from the external battery. The external battery is still fully charged, but the audiomoth wont record. When I plug in the battery the green light comes on, the way it does when I plug it into the computer. Could it be that it can't recognize a battery connected through USB?