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Lots of 0 bytes files...

in Device Support

By some reason, I've got lots of 0 bytes files and some correct wav files:

Unit is 24410E085728D5E5 v. 1.0.0 with firmware 1.8.0

SD card (SanDisk Extreme 64Gb U3 A2 XC V30) is far from beeing full. This is the configuration:

Device ID : 24410E085728D5E5

Firmware : AudioMoth-Firmware-Basic (1.8.0)

Time zone : UTC

Sample rate (Hz) : 96000

Gain : Medium

Sleep duration (s) : 1500

Recording duration (s) : 300

Active recording periods : 1

Recording period 1 : 04:00 - 20:00 (UTC)

Earliest recording time : ---------- --:--:--

Latest recording time : ---------- --:--:--

Filter : -

Trigger type : -

Threshold setting : -

Minimum trigger duration (s) : -

Enable LED : Yes

Enable low-voltage cut-off : Yes

Enable battery level indication : Yes

Always require acoustic chime : No

Use daily folder for WAV files : No

Disable 48Hz DC blocking filter : No

Enable energy saver mode : No

Enable low gain range : No

Enable magnetic switch : No

Enable GPS time setting : No

Any idea on why could this be happening? Are 64Gb SDs not reliable?

9 comments

9 Comments

Agustin Lobo

Sep 28, 2022

OK, then I take as lesson learned that we have to check batteries with a tester prior configuration and not rely on the "BAT 4.6V" reported by the config app, in particular for lithium batteries. Thanks a lot.

Alex Rogers

Sep 28, 2022

Replying to

It depends on the tester and whether you can configure the tester to recognise different battery chemistries. The AudioMoth measurement of 4.6V is accurate. The problem is that measuring the voltage of an Energiser Lithium Ultimate battery doesn't give a very good indication of the state of charge since the discharge curve is quite flat. This is the plot from the data sheet of the Energiser Lithium Ultimate battery. It has a strange wobble in the 1mA line which doesn't help either.

With an alkaline battery the discharge curve is much steeper so the cell voltage gives a much clearer indication of the state of charge.

With alkaline batteries, a voltage of 4.6V is fully charged, and the voltage drops steadily with use. For Energiser Lithium Ultimate batteries you probably need to keep track of their days of use (using the value in the Configuration App) in order to estimate how much capacity they have left.