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Charging USB devices without an inverter or AC power

April 22, 2017
USB charging

I recently purchased a bunch of dual USB 3.1A 12v to 5v plugs that can be surface mounted for my RV.  The idea was to tap into existing 12v or run new 12v DC power to them in the rig.  If I was boondocking I could charge phones and tablets directly off the battery without the conversion waste from converting from 12v DC to 120v AC using an inverter and back to 5v DC using the little 110v wall plug.  It is more efficient to tap directly off the batteries and pull 5v off them as every time you convert from AC to DC and back you waste power.

This solution is also much cleaner, there are no need to carry around a handful of USB AC charging bricks and adding power bars everywhere to deal with the fact that most take up more space than a single AC receptacle.  I also considered the AC power plugs that also have USB but decided I wanted my USB to be directly tied to the DC power of the rig as opposed to the AC.

The install process was quite easy requiring little more than a hole saw that was the size of the plugs, a few feet of 14ga wire, wire strippers, Marr connectors, solder iron and solder.  The install took little more than 30 minutes, with the most complex part disconnecting the battery as I do not have a battery cutoff switch and verifying everything was wired correctly in the end.

I found the plugs online for a few dollars each.  The ones I choose look like the traditional flush mount cigarette lighter plug with 2 USB.  They are able to do 3.1A which will charge a full size iPad.

USB plug

USB plug

From → RV Tech

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