UBC Portable Power Box

instructions and parts list

You'll need these, or something like these. I got mine from E-Bay. You can get yours anywhere. The important part is 300 watts for the inverter. No higher. It will kill the battery really quick. All these pics have been sized down for the page. Right click and "view image" you can see the full size.



12volt Cig Lighter Socket

12v Rocker Switches

300 Watt Inverter

Marine Battery Box

USB Outputs

DC Volt Meter

Short Battery Connector Wires

Battery Terminal Post Connectors only if needed

Battery from O'Reillys

1. I started by drilling a hole in the back, for inverter breathing. Then I glued a piece of screen over the hole.

2. Then I drilled the holes for the meter, the switches, the cig lighter socket and the inverter. Note: not everything fits just by drilling, but this is soft plastic. It can be shaped with a knife or a plastic file. A step drill works great for this. I added a "faceplate" to my inverter, just another piece of plastic.


3. I mounted the inverter to a piece of wood, then screwed the wood to the side of the box. It holds fine!

4. Cut the power connectors off all of the output devices. You can save them for another project. We're going to be soldering the wires directly to the bus.

5. I glued the USB bar onto the top, then drilled a #30 hole to run the wire from it. Note: Mine is actually 2 USB bars connected together. I use this for a church, I need a lot of USB outs.

6. I drilled 2 holes to fit the bolts, mounted onto the top left of the box. These actually serve 2 purposes. 1) I charge the battery from these bolts 2) they are there for attaching alligator clips onto, for a universal 12vDC power out.. Make sure you file a + into the positive bolt head. Paint the top of it, even.

7. Now, work backwards so there's no power to arc anything. I made a bus by cutting 2 copper wires to fit and RTV'd them into each side of the switch gang. I labeled one + and one -. Then I soldered the switches appropriately. Add on the meter, the cig lighter socket & the USB bar, we're almost there!


8. Attach the POS bus to the POS bolt and the NEG bus to the NEG bolt. Then connect the battery cables to the bolts & tighten real tight! Now... if you bought the kind of battery that has terminal bolts sticking out as well as posts, you don't need the terminal clamps.

9. Hook up the battery & everything should work as advertised.

If you run into a snag somewhere, call or text if you have my number... otherwise email me.