February 23, 2014

Project: Tiny Mint Tin Switched 9v Battery to Anderson Powerpole

We enjoy using a Byonics TinyTrak4 as an APRS TNC when operating portable with an HT in the back country.  This remarkable device, when coupled with an HT, transmits GPS position to amateur radio APRS receivers that pass the information along to the Internet.

Byonics TinyTrak4 TNC

The Byonics TinyTrak4 can run on 9v to 12v and the adapter cable is wired with Anderson PowerPole connections.  We prefer to keep our pack weight to a minimum when hiking so a 9v battery is an excellent choice.

Our first design was to simply solder a 9v battery clip to a pair of Anderson PowerPole connectors.  This worked well; however, we found it was also rather fragile and it didn't take long for the whole thing to fall apart.

While rummaging around our junk box we noticed a diminutive mint tin slightly larger than a 9v battery and this became the inspiration for an improved battery pack design.  The basic idea is to use heavier gauge wire for the Anderson PowerPole connectors and hide the battery and fragile 9v clip inside the tin.  Adding a switch would provide a convenient way to switch power on/off (there is no switch on the TinyTrak4).

NJ2X - mint tin transformed into a switched 9v battery to Anderson Powerpole

NJ2X - mint tin open revealing 9v battery and connections


  1. With a 9v battery in the enclosure, layout where to place the exit holes for the wires and switch
  2. Drill a hole large enough for the two wires plus a little margin for heat shrink tubing
  3. Drill a hole for the switch.  If necessary, drill a semi-circle on the lid edge so it will close with the switch installed (see picture).  Remove the burrs.
  4. Solder the positive wires to the switch
  5. Solder the negative wires together
  6. Wrap all the contacts in heat shrink or electrical tape to prevent short circuits with the case or battery
  7. Tie a simple knot using the black and red wire that will exit the box
  8. Pass the black and red wires through the exit hole leaving the knot on the inside of the box.  This will prevent strain on the battery clip and contacts.
  9. Slide a short length of heat shrink over the two wires exiting the box
  10. Solder the Anderson Powerpole ends on the wires and clip into the Powerpole connectors
Correct configuration of Anderson Powerpoles: "Red Right Up"

Voila!  A handy little 9v battery to Anderson Powerpole device.  Perfect for powering up a Byonics Tiny Track4.

NJ2X's portable APRS setup Kenwood TH-F6A, Byonics TinyTrak4, Byonics GPS2, and home brew 9v to Powerpole battery pack

Good DX and 73, NJ2X

By Michael W. Maher

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