Factors Affecting Battery Life

Battery Quality

For a single type of battery, different brands and models can vary in their performance.

For AA batteries, the Song Meter Configurator app assumes you are using Energizer, alkaline batteries when it estimates battery percentage and run time. Different brands of AA batteries may not last as long as the app's estimations, even in ideal conditions. Rechargeable NiMH batteries will die significantly more quickly than the app's estimations.

For 18650 lithium-ion batteries, the Song Meter Configurator app assumes you are using Wildlife Acoustics branded batteries we sell in the United States. These batteries have a manufacturer-stated capacity of 3500 mAh per battery. Batteries with the same stated capacity from a reputable manufacturer should perform similarly to Wildlife Acoustics branded batteries.

SD Card Power Consumption

SD cards vary significantly in how much power they require. Even SD cards of the same model and size from the same manufacturer can exhibit this variation. The power consumption of an SD card can have a noticeable affect on the power consumption of the Song Meter Mini Bat 2 overall.

Ambient Temperature

Most types of batteries experience diminished performance in cold weather compared to room temperature. The magnitude of this effect is different for various battery chemistries. For example, alkaline AA batteries can have their performance reduced by 50% or more in freezing temperatures.

Level of Bat Activity, or Trigger Ratio

For ultrasonic recording in the default, triggered mode, more frequent bat activity will prompt more frequent recording, drawing more power from the batteries and filling up more SD card space. In the Estimate Battery and Card Life Window, the Trigger Ratio can be adjusted to set the percentage of time during ultrasonic recording that the Song Meter Mini Bat 2 is assumed to be recording nearby bats.

For example, if you have the Song Meter Mini Bat 2 scheduled to run triggered, ultrasonic recording for 10 hours each night on a bat flyway, there may be significant periods of silence in between passing bats. A Trigger Ratio of 10% may be a good starting point for estimating your battery and SD card life during this kind of deployment.

However, if you have the Song Meter Mini Bat 2 deployed near a bat roost, or if it is running a schedule limited only to the periods with the most bat activity, setting the Trigger Ratio to a higher value will provide a more realistic estimate of your battery and SD card life.