Factors Affecting SD Card Estimations

When you select a preset SD card size in the Estimate battery and card life window, the estimation assumes that all of the card space is completely unused. Reformat the SD card before each deployment to ensure that this is the case (see Format the SD Card).

For acoustic recording or non-triggered ultrasonic recording, SD card usage is very predictable. Assuming the SD card used during the deployment is freshly formatted and does not encounter an unusual issue, the date at which the card fills up should be very close to the estimation shown on the Estimate battery and card life window.

For schedules that involve any periods of triggered ultrasonic recording, card usage is much less predictable. The trigger mechanism means that the Song Meter Mini Bat 2 only saves audio to the SD card when it detects nearby bat activity or other ultrasonic sounds. More frequent ultrasonic activity near the microphone will result in more card usage.

For triggered ultrasonic recording periods, the estimation uses the Trigger Ratio setting to decide what percentage of each period will be saved to the SD card as recorded audio. For example, when the Trigger Ratio is at its default setting of 10%, the Song Meter Configurator app assumes that 10% of the length of each ultrasonic recording period is recorded to the SD card, and the remaining 90% of each period is unrecorded silence.