Having been out on the road a while now, I’m catching up on the remodel that got me here.
After I finished with the 110v AC (alternating current) system, I turned to the 12v DC (direct current) system. This is what you may be familiar with as what you find in your vehicle. The cigarette lighter outlet (more properly referred to as a “bayonet” port) is a 12v DC outlet. You probably use yours most with a phone charger or GPS navigation system.
Recreational vehicles contain both systems. The beauty of the 12v portion of the system is that it can and does operate free of outside electrical hookups. The pain of it is that you must find a way to keep your house battery(ies) otherwise charged up.
Though this system charges via the 7-pin plug that also operates the RV’s external safety lighting (for a trailer) or via an internal hookup (for a motorhome) while you’re driving, that charge only lasts a few hours, especially if you use lots of interior lighting, charge your devices, or operate 12v accessories such as fans or radios.
The two most popular methods to charge house batteries are the use of a generator (internal in larger RVs or external in smaller ones) or a solar panel system. As of this writing, I am getting ready to have a solar charging system installed, but will also carry a gas-powered external generator just in case. Properly hooked up, both of these methods can charge both 12v and 110v systems.
Foredeck 12v Charging Stations
Since I had begun with the 110v outlets I put in up front, we’ll continue with the 12v charging outlets I installed on the starboard side of the foredeck’s center console.
The first thing I had to do was figure out where to attach the wires to tap into the trailer’s existing 12v wiring system. That would obviously be through the fusebox, and I knew from my work with the 110v system where that was. It’s located amidships, near the floor and beneath the cutout for the microwave oven in my galley kitchen cabinets. I just had to release and drop the top half of the access panel cover to reveal the ports.
The trick was taking time to familiarize myself with the difference between the 110v circuit breaker panel (just like you have in your house) and the 12v fuse panel (just like you have in your car). the fact that I have experience working with both really helped me discern what I needed to work with and what I needed to leave alone.
For both types of hookups, one must access the back of the fusebox—to lead each wire to the proper circuit breaker or fuse for each circuit—and what’s called a “bus” — a metal bar screwed, in this case, into the floor of my trailer beneath the kitchen cabinets. This serves to ground all circuits to the steel frame of the trailer, which ensures—as it does in a house—that I won’t be electrocuted when I use any of my electric appliances.
As you can see in the picture here, the length of the existing wires only allowed it to be pulled so far away from the cabinet. This made getting my hands and lower arms inside to manipulate the wires and screws rather difficult, as it severely impaired access.
I knew it would be very easy to get confused about which wire was what, which can be extremely dangerous when working with electricity. So even though I was working with the batter disconnected and no outside electrical hookups, you can bet I worked very slowly, methodically, and triple-checked every connection before I made them. I also was pretty anal about labeling the lines with my labelmaker. Yes, I love that thing. It has probably saved me, more than once, from accidentally killing myself.
To give you an idea of the tight quarters I was working in, this photo shows how the wiring for both 110v and 12v had to run beneath the kitchen sink inside the cabinets and out beneath the port side dinette bench.
This all served as a chase to keep the wires together and relatively protected from damage, while also keeping them out of sight for good looks. Very useful, but not easy to work inside!
In the 110v installation blog, you saw how I pre-drilled the individual holes for the 12v USB and bayonet chargers. They came one of each to a two-hole cover plate, which I used as a template to place the holes.
The individual positive wire running from each of these circuits included an inline fuse. That is, they SHOULD include such. Some of those delivered in my orders already had them. In others, I had to splice the fuse holders in myself, as you see here. This ensures that if one outlet goes bad, it doesn’t drag the whole system down, and it’s also a good protection against fire. And I like that.
The photo below shows how the double 12v outlet is wired, which you can’t see once it’s installed, because the wires are underneath the foredeck top shelf panel.
Below, you can see the pre-drilled holes of the second grouping awaiting placement of the components of a second set, while the top set is fully installed.
After I had the second set of 12v outlets installed, I was so insanely glad to be able to plug in a 12v fan to move some air around in the hotbox my trailer had become already in the early summer swelter! It was a well-deserved treat for a job well done!