Where to Put That Plug?

By Bill Moore

Posted: 01 Nov 2009

The beauty of charging an 20-mile range plug-in hybrid like the one siting out in my garage at the moment is that it can be charged in about six hours overnight on 110 volts through a 15 amp circuit. In my early 70s era two-car garage there are three outlets: one on the back wall and two, oddly enough, on the ceiling; and as strange as it might sound, it turns out that one of them is perfect for charging the Plug-In Conversions Corporation 6.1 kWh NiMH battery pack bolted into the spare tire well of our car.

One of the first questions you need to ask yourself before you decide to buy that Volt, Leaf, Think or Tesla Roadster is where are you going to plug it in? If you're a home owner with a nice attached garage, then the question is a bit easier to answer. There's probably at least one standard 110V outlet somewhere in the garage, but you'll want to make sure what else is on that circuit. In our case, the ceiling plugs share the circuit with the spare bedroom above the garage. Being your typical empty nest couple, that bedroom is where the occasional extra guest gets assigned. There's a ceiling fan in there, a couple lights, small television set and the ironing board. Below it in the garage is connected the electric garage door opener (yes, we do have it nice compared to many others). That outlet has a spare receptacle and it's here we plug in the bright yellow 12 gauge, 25 feet-long extension cord you see hanging from the ceiling in the above photo.

I had originally worried about stringing the cord from the back of the garage to the rear of the Prius where the plug port is located. I envisioned people tripping over it or running over it as we pulled into and out of the garage. As it turned out, the garage door motor outlet appears to be perfect location for providing power to plug-in cars. At the moment, most Prius PHEV conversions have their charge plugs located on the left side of the rear bumper and since most people don't back into their garages at night, it's about as far as you can get from the typical outlet placed on the garage back wall.

There are, of course, all sorts of places on the car for putting the plug. The charge port of the Tesla Roadster is just behind the driver, while the Volt's is just in front of the driver's front door. The Nissan LEAF's charge point in integrated into the front of the car. So, having the plug mounted on the ceiling at or near the center of the garage turns out to be a pretty versatile location for charging as wide a variety of plug-in electric cars as possible given all the possible charge port permutations on these vehicles. Having it on the ceiling also keeps the cord off the floor. As you can tell from the photo, I've used a couple simple bungee cords to keep the extension cord almost above head level when not in use. I'll refine it when I get some time, but for now it works great. The garage door slides under it, so its out of the way. When the doors down, its easy to grab the plug end. It also helps that the cord I bought has a lighted plug making it easier to plug into the car in a darkened garage.

I've had a couple developers and contractors ask me where I'd recommend putting the outlet for future electric cars and I have to heartily endorse my set up, which is purely fortuitous. If you have the luxury of new construction, I suggest running a separate circuit for that plug and if possible wire it for 3-phase 220V. While my 6.1 pack charges on 110V overnight -- we plug it in just before going to bed at 11 PM and unplug it first thing in the morning about 7 AM -- the bigger packs in the Volt (16kWh), Leaf (24kWh) and other electrics headed our way, could take longer than 6 hours to recharge at 110V; 220V at 30 amps would be much better.

Of course, some day the ideal situation will be charging inductively from beneath the car: no cord needed. Just pull in, watch for a light on the dash to turn green and you can forget about the car until next morning. But how in the world you "plumb" for that, I haven't a clue. Pour the equivalent of a garage sump pump hole?

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