12-volt Accesory Plug Installed

One of the great design achievements on our 32' Bayliner is the amazing use of the space available. Below the salon in the main cabin is the master stateroom containing not only locker space and a sink but also a king-sized bed. At the head end of the bed is room enough to sit up and read, even kneel with plenty of head room. The space tapers from there until at the foot end the space is only a little more than 24 inches--plenty of space to turn from side to side. The 

Interior cutaway drawing of the Key of Sea.
Note the 'step down' to the lower master stateroom & its bed.

bottom line is that the space is roomy and cozy for us.

But the room has a problem we have been unable to solve up until now. I use a c-pap machine to aid in my sleep apnea. It uses only 12 volts to run but, like most 12-volt devices (you own more of them than you might think), it is sold with a standard adaptor that uses the 110-volt power found in the home and changes it to 12-volts. But what if, as is the case on my boat, your power system is already 12-volts?

I could just plug into the 110-volt power source next to the bed and when we are on shore power that works fine. But when we are not on shore power we must rely on the house batteries, the four deep cycle batteries in the bowels of the boat, to run our electrical devices. The batteries are good for about 3 days before they must be recharged by running the engines or the generator I recently installed on the fly bridge.

If I chose to use the 110-volt plug while on battery power it would require the use of the on-board inverter which changes 12 volts to 110. The inverter is located in the service tunnel a few feet from the foot of our bed. When running it makes a steady noise that would keep us awake. So that wouldn't solve the problem. 

I've been looking at this problem and trying to enlist the help of my c-pap supplier in this effort. Unfortunately my local supplier had only one unacceptable solution. So I searched the internet and a few weeks ago I found a nifty attachment available from the manufacturer that plugs directly from the c-pap device into a 12-volt source. Hmmmm . . .

The new plug in the master stateroom ready for use.

The end plugging into the power source is one of those cigarette lighter type plugs you see so often in automobiles to power the hand-held gaming, music and video devices which have proliferated in the past few years.

At a visit to my favorite marine store I discovered a wall plug part that the new adaptor could plug into. A few connectors and some 14-gauge wire and I was out the door.

I noticed a long time ago that there were two-pronged, odd-ball plugs built into the wall in both the master and the v-berth staterooms. I have no idea what they powered at one time. I didn't even know if they were hot. My multi-meter quickly answered that question. Yes, hot and 12-volt hot. YES! This could be my power source as long as the circuit could handle the amperage of the c-pap machine. The power need listed 5 amps on the bottom of the machine. Seemed like a big draw for such a little device. A call to the manufacturer and I discovered that was the amperage draw for both halves of the device. Away from home I generally don't use the humidifier half of the machine. There's plenty of humidity at sea already! So the circuit should handle the c-pap no problem.

My c-pap machine plugged into the new
power source and working fine!

I removed the old useless plug from the wall and discovered the hole that had been drilled was not a large enough diameter for the new plug. This added a new mystery to the project. How to enlarge the existing 3/4-inch hole to the 1 and 3/16 inches needed without defacing the beautiful cabinet it was built into?

My local Harbor Freight dealer had an interesting drill bit that I thought might do the job. It is conical shaped but with levels indicting the diameter of the hole at each step. I asked an employee, explaining my situation and he assured me it would work. 

Finally, having accumulated what I needed to do the job and a bit of knowledge regarding how to go about it, I was ready to get after it.

After weeks of thinking about it, gathering the tools and parts needed to do the job, the job itself was a snap. It only took about a 1/2 hour and it worked the first time! I was really kind of shocked. Usually I wind up calling someone to come fix the mess I made. Not this time.

The new plug works great and now I can sleep in my nice comfortable bed whether we are on shore power or the house batteries.