The Batcorder Box Extension provides a reliable and functional solution for long term monitoring projects such as those used for wind farms or extended monitoring of roosts.
The batcorder is contained within a robust plastic box. The borderline microphone is installed in the box cover and additionally protected by a foam ring. A specifically designed control module allows connection of 6V to 17 V batteries. The set comes with a 6V / 12 Ah lead-gel rechargeable battery (normal runtime is about 20 days). This can be recharged using 6V solar panels (optional). Thus, the maximum runtime of the batcorder is limited only by the SDHC card's capacity. Usually you can expect a 32GB SDHC card to last 2 to 3 months at a site with 'average' activity.
The Batcorder Box Extension performs a similar role to the Wind Turbine Extension Kit, which has proved its reliability at multiple wind farm sites across Europe. As with the Wind Turbine Extension Kit, the Batcorder Box Extension contains a microphone test capacity to detect deviances from calibrated sensitivity. If the microphone is damaged by rain or dirt, the control module will report this via SMS. The box can also be locked with a padlock providing security for the batcorder inside.
At the end of each recording interval (night), the box also sends a detailed status update to a nominated mobile phone. This message contains the number of recordings made that night, overall number of recordings, memory capacity of the SDHC card, microphone sensitivity as well as other error messages such as an empty battery. All you need is a standard SIM card, which you can install yourself easily. Obviously a prerequisite of the system working is reasonably good mobile coverage at the location (this can be checked prior to installation on a normal mobile phone).
The box should be set up to minimise reflection from surfaces above, below, in front and to the sides, to reduce echos. If installed on a mast, the box should face away from the main direction of weather to reduce rain exposure of the microphone. Electromagnetic fields (e.g. power lines) as well as known ultrasound sources (e.g. ultrasound based humidity sensors) should be avoided. We recommend a test before installation if such sources cannot be avoided. For monitoring over multiple years, we recommend you de-install the Batcorder and microphone over winter to reduce unnecessary wear and tear. Microphones age more quickly than Batcorders and should be tested after a year.
In addition to the Batcorder Box Extension you will need:
* SDHC card (up to 32GB)
* SIM card to send a daily status message
Solar Panel Power Production
The solar panels are of sufficient capacity to recharge the batcorder after each night of recording (therefore deployment time will only be limited by the capacity of the SDHC card). However, if there is a prolonged spell of cloudy weather, sufficient recharging of the batcorder may not occur. If this occurs, the user will receive an SMS text message notifying them of a low battery.