Perplexing Power Plugs…
AC plugs and sockets are easy. They have been standardized for many years. There is no question what you should use and they are readily available. 12V DC sockets and plugs are another matter. The only real standard that I know of is the ancient cigarette lighter socket. It’s bulky, and electrically speaking, not a very good connector though.
I had planned on putting 5 DC plugs in my truck. The only ones I had any specific plans for were in the sleeping area, so I could plug in a DC electric blanket. The others are in the kitchen, or in the computer area just in case. I have some Lithium Polymer battery chargers that run off of 12V for example.
I mounted some cigarette lighter sockets in blank electrical outlet covers but I was never really happy with the result. It almost worked, but the sockets are so deep that they pressed up against the back of the handy-box and in some cases bowed out the cover. It was also very difficult to get all the wires and wire nuts back into the handy-box because that big fat connector takes up so much space.
I finally got fed up and decided to at least look for an alternative. I had a bunch of Anderson Powerpole connectors in my junk box from a project years ago, but they are designed as an in-line cable connector, not a bulkhead mount connector. I threw some in my pocket and started browsing the local home improvement store (Lowes) and found an electrical box cover with a square opening intended for modular data and phone connectors. It just happens to be a perfect fit for the Anderson Powerpole connectors in a 2 by 2 array. I slightly filed the opening to bevel the front side for easier plug insertion but that was it.
I just soldered the wires into the contacts, or in my case soldered the wires to the wire stubs left over from the previous project, shoved the connectors into the mounting plate, and gave the whole thing a good coating of Goop. I love Goop. It’s sort of the duct tape of adhesives. It sticks to almost anything, including smooth plastic, remains a bit flexible forever, and can be peeled off if you ever really need to.
The downside is that when I buy 12V electrical appliances, I will have to cut off the cigarette lighter plug and solder on the mating Powerpole connectors. The upside is that I will have real connectors that are up to the task of carrying up to 30A without falling out or making intermittent contact. I can also plug in up to 2 appliances per outlet, where before I could only plug in one.
If you are not familiar with Powerpole connectors, here is a link:
http://www.mcmelectronics.com/...0&CAWELAID=220239965
They are not cheap, but not overly expensive either. The individual connectors are sexless, meaning you can plug any connector into any other connector. The little plastic housings have dovetail keys that allow you to lock them together. When you do that you can create a polarized “plug” and mating “socket” without any possibility of a reverse polarity connection, because they simply won’t fit. The housings come in red and black which is also a handy visual reference for polarity.
The contacts are almost fully enclosed in the plastic housings, making it difficult to touch them, and while it is not as critical for 12V as it is for 120V it’s still a nice safety feature. The contact area has a heavy silver plating which gives them their excellent electrical properties. They have a nice “over center friction lock feel” on engagement so they don’t just fall out, but they also don’t hang on so aggressively that you can’t get them out without ripping your fingers off.
In a world where cheap is the definition of good, they will probably never become an industry standard, but they have just become my standard. As always I have provided pictures that can be viewed under keyword “Stealth”.
To be continued…