$20 18v POE battery hack

On 12/09/2013, in How To, by Norman Dean


Inspired by a post over at the Ubiquiti forums here.

I was tired of lugging a huge role of ethernet cable around whenever I needed to do a site survey when install wireless internet in the woods of Southern Oregon. So I decided to build a portable battery Power Over Ethernet injector to power my wireless radios.

What I did is not quite elaborate as what is shone at the Ubiquiti forums but it is by far much cheaper, $20 to be exact (not including various supplies like the cabling).

Parts needed:

Battery charger – http://www.harborfreight.com/charger-for-cordless-18-volt-tools-67031.html

18v battery – http://www.harborfreight.com/18-volt-battery-67029.html

Ethernet cabling as long as you need and 1 RJ45 connector.

Tools: Wire cutters, Soldering iron, Screw driver

Crack open the charger and cut out the charging circuit. Get your soldering iron hot while you cut open one end of the ethernet cable. You can cut off the orange and green wires as you will not need them if you are only powering a radio. Strip the insulation from the blue and brown pairs of wires, twist them together and solder the same colored pairs together (brown and brown white – blue and blue white).


The blue wires are positive and the brown wires are negative, solder them to the corresponding terminals on the inside of the charger box, they will be easily identified with a plus and minus on the underside of the unit. After you are done soldering you can screw the assembly back together where you will have a nice hole left for the cable to exit. Crimp the other end of the cable just like you would any other ethernet jack and boom your done. You can plug the POE pack onto the battery as you need and still have a functional battery for use in a drill (I would suggest you purchase a second charger so you can charge the battery).



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