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The Nevada Bat
Technical Notes Archive

Long-Term Monitor Fabrication

       
  There are probably a lot of different ways to house a long-term bat monitoring station. These various configurations evolve based on the equipment deployed, the monitoring environment, and the tools, skills, and materials at hand.  
 

 

 
This particular Anabat based configuration, which I've been tweaking out for field use with Mike O'Farrell, has evolved into a relatively compact package. Several are currently in service in Southern Nevada.

Similar systems have been built and used in the field by Bill Rainey and Chris Corbin over the last year or so, and have also proven useful in the field. Tracy Allen has also joined the quest, working with Bill Rainey to improve transducer extensions for wet climates.
     

Basic Preparation of the Equipment Enclosure
  Gather up all the tools, parts, and materials that will be needed to prepare and assemble the equipment package. Industrial strength Velcro material ( 2" width ), lighter fluid, wire ties, wire tie anchors, alcohol swabs, and rubber foam weather stripping should all be at hand to help the work go smoothly.

( Click here for a resource list... )

 
  The long term monitor package is packaged in a NEMA type fiberglass enclosure. These sturdy enclosures are weather resistant, easy to machine, and relatively low cost. I use the case style that has the lockable hasps.

The first step in preparing the NEMA enclosure is to remove all labels from inside the case. Lighter fluid ( naptha ) and a ribbed razor blade make the job a lot easier. The inside front and back surfaces should then be cleaned with an alcohol wipe to insure the best adhesion of the self-sticking Velcro and wire tie anchors.

Three six inch lengths of the Velcro hook material are cut and applied to the areas where the Anabat Detector and Recording ZCAIM will be positioned.

 
 

 
  Two of the strips are set in one inch from the edges of the outside corners inside the lid of the enclosure. The remaining strip is cut in half lengthwise and applied next to the first two strips to widen their footprints to the size of the Anabat equipment cases.  
  The next step is to drill the holes for the cables to enter the bottom of the enclosure. I do this in two steps . . .

First I drill a pilot hole with a 1/16" drill. Then I use a sharp countersink drill bit to ream the hole out to the finished size. I find this gives a nice clean hole for installing the cable glands. I use a 1/2" countersink for PG7 cable glands, and a 3/4" size for PG11 cable glands.

 
  It's a good idea to wear gloves and a dust mask to minimize exposure to fiberglass dust, and be sure to remove any residual dust with a moist rag or tack cloth. You can also employ a shop vac to keep the dust controlled.

While the smaller PG7 thread cable gland works well for most cables, the larger PG11 type is needed to connect an extension transducer.

As seen to the right, the fixing nut of the PG11 gland is large enough to accomodate the DIN connector of an Anabat transducer extension cable.

The enclosure size used here can accomodate one PG11 cable gland on one side of the batteries, and two PG7 cable glands on the other side.

 

Equipment Preparation and Installation
  Next, the batteries are readied for installation. After wiping the front and back surfaces with an alchohol swab, and letting the surfaces dry, a Velcro "fuzz" strip is placed on the back of each battery, and a strip of self adhesive rubber weather strip to the front. The weather strip will cushion the small gap that exists between the batteries and CF Zcaim, which is mounted on the lid of the case.

 
  Next the batteries are fitted into place. Note the fused jumper that is used to connect the two 6 volt batteries in series. The fuse I use is a 1 amp quick acting type.

At this point I usually place a couple of peel and stick wire tie anchors to the back wall of the case above the batteries.

You can also see how close the holes fit around the batteries ... not very much wriggle room !!

 
  The solar panel charge controller ( This one is a home-brew unit ) and HOBO logger are installed using velcro strips. An external HOBO temperature probe is installed in one of the cable glands, and the wiring is routed and secured with nylon wire ties. The transducer extension cable is also installed temporarily, to allow final testing of the system.

Once tested, the battery wires are disconnected, and the battery terminals covered with tape or terminal caps until the system is deployed.

 
  Velcro fuzz strips are applied to the bottoms of the Anabat detector and CF zcaim next.

Cut and apply the Velcro strips so as to allow access to the batteries !!

For the strongest bond, clean the case bottoms with an alcohol wipe before applying the strips. I also like to let the strips adhere for a day or so before actually mounting the gear.

 
  The Anabat gear is mounted to the Velcro hook strips on the inside of the lid. The detector-to-CF cable just fits in, with the excess looped and secured with wire ties. The power cables are also secured and connected.

The cable from the remote transducer extension is plugged into the detector, but not tied in with any of the other cables, as it will be disconnected for storage and transport once the system is charged and bench checked.

 
  It is important to note that Gel type batteries should always be stored in the charged state. So give them a full charge before storing the system for any length of time, and before field deployment. This also gets a solar powered system off to a good start !!  
 

 
           
  This is not meant to be the definitive design for long-term bat monitoring systems... only an example. Field conditions require equipment configurations to be adaptable. This configuration was designed to achieve the most compact size possible ... and doesn't have much room to expand.

The dual 6 volt, 4.2 Amp-hour battery setup, with a 5 watt solar panel seems to work well for Southern Nevada. The batteries provide ample backup capacity for 3 to 5 nights monitoring, and can be fully replenished in a single summer afternoon. A 7 Amp-hour battery could operate the system for 10 days to 2 weeks, where long periods of overcast weather become a problem.

In the system shown below, Bill Rainey deployed his monitoring system in what must be considered very dire circumstances for a solar powered application. In this case, the oversized external battery, in the container to the right, provided the extended capacity needed to backup whatever power the solar panel could collect. You might also note the Anabat transducer extension / reflector configuration fabricated by Tracy Allen, mounted at the top of the equipment pole.

For your specific application, you may prefer to start out with a larger enclosure, a single 12 volt 7 AH battery, and 10 watt panel, until you can gauge the solar performance in your area. The 10 watt panel provides the additional charging current needed for the larger battery, and can make up for lost solar efficiency due to overcast skies, or short winter days. Sometimes, solar power just isn't practical, and a very large battery or auxiliary power source needs to be used. Adaptability is critical.

  
           

Tony Messina, Las Vegas, NV - page last updated 09/30/2004