Installing 12-volt USB plugs in RV


Step 1: Locate were you want the plugs

I wanted my plugs in our bunk beds.  In each bunk there was already a 12-volt LED light.  I removed the screws that held these lights to the wall so I could trace their 12-volt source.  I decided to put my plugs right next to the LED lights.  I verified there was no pumping, wiring, or framework behind where I was going to drill hole for the plug.  I drew a circle where the plug hole needed to be.

Step 2: Turn off Power to trailer

Turned off both the shore and battery power.   Started by disconnecting shore power.  Followed by disconnecting the negative battery terminal.  While I was at it, I checked the water level in my 6-volt golf cart batteries.  All was good.  

Step 3; Drill hole in trailer for plug

I used a cordless electric drill, with a small drill bit to starting creating my plug hole.  To create the hole for the plug, I then drilled a series of small holes, trying my best to drill inside the circle drawn on the paneling wallboard.  


Step 4: Trim Cutout

Once the drilling is completed, the center of the hole would not come out.  I used a box knife to finish cutting out the hole.  I then had to trim back the paneling a little more to actually get the plug to fit.

Step 5: Fishing out power source

To fish out the power source I needed something to hook the wires that were connected to the LED light.  I used the ground wire of heavy gauge power wire.  I reach around until I my little hook snagged the LED light wires.  I then pulled out the wires until I found where the LED light connected to the 12 volt wiring.


Step 5: Hook up USB plug

I bought a USB plug from an RV store.   I would have thought it would have the same colors for wiring as the LED light.  No it did not.   The auto USB plug I got had a red and black wire.  The LED light connected to the power source had a white and black.  Ok does black go to black?  No it doesn’t.  On the USB auto plug I bought the RED is positive and BLACK is negative.  Whereas the LED light had a BLACK which is positive, and WHITE wire for negative.  I wired the RED from the USB plug to the BLACK wire from where the LED light connected.  I wired the BLACK from the USB plug to the where the WHITE of the LED light connected. I even used the same crimp fittings.


Step 6: Reconnect batteries and testing out new USB plugs

I reconnected the batteries, and then tested out my new USB plugs.  I plugged in my phone and it started charging.  I then plugged in a small USB fan I had.  It worked great.  Now I can charge my phone and use the fan on those hot evenings.

Final Installation


  1. Nice mod. Can you post a pic of the final installation?

    1. Thank you for pointing out I didn't post a picture of the final installation. I have now updated the post to include the missing picture.


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