• Nov 1, 2010



When discussing electric vehicles and charging standards, things can get a bit confusing. Progress has been made in terms of unification, with the J1172 connector becoming a standard in most of the world. However, nomenclature still brings about plenty of conversational disorientation. Did you know modern electric vehicles (EVs) such as the Nissan Leaf have the charger built into the car? If this is so, what, you may ask, is the $2,200 Aerovironment "wall charger" that wants to sell me to charge the Leaf (or another EV)? Well, that wall charger or charging station is really just a device that safely allows electricity to flow. These "chargers" and the protocols established to create them are known as EVSE (electric vehicle supply equipment), and they enhance safety by enabling two-way communication between the charging station and the electric vehicle.

The term EVSE has been in use for a long time, and the 1996 NEC and California Article 625 defined (PDF) EVSE as:
The conductors, including the ungrounded, grounded, and equipment grounding conductors, the electric vehicle connectors, attachment plugs, and all other fittings, devices, power outlets or apparatuses installed specifically for the purpose of delivering energy from the premises wiring to the electric vehicle.
This two-way communication ensures that the current passed to the vehicle is both below the limits of the wall charger itself and below the limits of what the car can receive. There are additional safety features such as a safety lock-out that does not allow current to flow from the wall charger until the plug is physically inserted into the car. While this new standard does result in additional cost to the consumer (versus just plugging into any 240 volt socket), their are benefits besides just safety. Adjusting the vehicle's on-board charger to make sure it doesn't exceed the power limits of the circuit it is plugged into is no longer required with EVSE. This is an important simplification to the charging process, and should help facilitate adoption of EVs in the future for people who could care less what current, voltage or wattage are.

[Source: California Energy Commission, AllCarsElectric | Image: Jonas Dalidd]


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  • 30 Comments
      • 4 Years Ago
      Somebody please explain why you can plug an electric car into any 120 outlet but need special equipment for a 240 outlet. My plan for the Nissan Leaf that I expect to order this month is to use 120 at home and outside "chargers" as needed. People who were lucky enough to have leased the EV1 have reported on the internet that range anxiety is vastly exaggerated.
        Raymondjram
        • 4 Months Ago
        240 VAC outlets at our homes are usually limited to large electric appliances. Since the EV is relatively new, no home has a 240 VAC outlet dedicated for it, but that will change. By law, all EVs must use a EVSE (Electric Vehicle Supply Equipment) for safety reasons, and each EV must have an EVSE for 120 VAC. To charge faster, the 240 VAC EVSE is recommended, since it allows more power (kW) to flow per hour, up to three times faster. Anyone who buys a BEV (Battery only EV) needs a better EVSE than what the car comes with. Unfortunately, you need to buy a unit that may need a permanent installation, and that is where its cost goes up. But there are some that can be made portable and attach to home outlets (stove, dryer, or water heater).
        • 4 Years Ago
        National Electric Code (NEC) 625-13 requires anything besides from 120V to have:
        Interlock, Automatic De-energization of Cable, and be Indoors (625-18. 625-19. and 625-29 respectively).
        "All other electric vehicle supply equipment shall be permanently connected and fastened in place. This equipment shall have no exposed live parts."

        http://www.madkatz.com/ev/nec1999Article625.html

        You need the special box to perform the interlock and de-energization. The manufacturers may also be playing it safe by falling under the "permanently connected and fastened in place" section.
        • 1 Year Ago
        My wife works at the Nissan plant where the Leaf is built. We were in the pilot program testing and gathering data on the Leaf for improvements. We drove our test model 2011 Leaf every day, in almost every situation imaginable for two years. The 'real world' range was between 75 & 85 miles depending on conditions. We LOVED our first one so much that when we had to turn in the test vehicle we replaced it with a new Leaf. Now we consistently get a real 100 miles range & sometimes a little more (we're old pros at energy management). You definetly need a level 2 charger (240v/40a) at home for convenience & safety. We have pulled into the our garage with 10 miles or less, plugged in for a couple hours, then gone out for dinner & a movie before going home to charge over night. You can't do that with a wall outlet. One time we had only been charging about an hour from 4 miles remaining, when we had to make a run to the local emergency room. We had 22 miles, which was fortunately plenty. With 110v charger once you are plugged in you are home for the night, period.
        • 4 Years Ago
        You need special equipment to plug into a 120V outlet too . . . but it comes free with the car. You pay extra for the 240V version which requires installation. Most people will have an electrician do it but you can do it yourself if you know a thing or two about home wiring. It isn't rocket science but you do have to pull permits with the local building department to do it legally.

        I'm not sure Nissan will sell you a Leaf right right if you won't get a 240V charger installed. The 120V system requires 18 hours to get a full charge . . . that makes the car very impractical. But if you only have a very short commute, you probably could get away with it.
      • 4 Years Ago
      There will be quite a few chargers but in my opinion these things shouldn't even be selling for $500....closer to $100-200 at most. Then again they have to recoup the huge EV R&D costs somewhere....
        • 4 Years Ago
        Well Nissan won't be getting the money. Unless they arranged some kick-back from aerovironment . . . which maybe they did. Which is all the more reason for me not to get that 'official' charger from them.
        • 4 Years Ago
        Did you even read the article? They are NOT chargers.
        • 4 Years Ago
        My bad, I know they are not chargers, but its a force of habit for me to still call them that.
      • 4 Years Ago
      It is J1772 not J1172.
      • 4 Years Ago
      Yes, they may not literally be chargers. But they are a crucial link in the charging process. And the term EVSE..... SUCKS!!!!!!!!
      That term in no way describes to any normal person what it is or does.

      Intelligent Charge Cord???

      Anyone? Anyone? Bueller?
        • 4 Years Ago
        "skier" :
        "Charging Station" is one of my preferences.
        But everyone is so freaked out about using the word charger that it seemed to close.?.?
        Also... Charging Device? Charging Portal? Charger Access Device?

        To be funny... The chargers charger. Bad, I know.
        • 4 Years Ago
        It's a "charging station", http://en.wikipedia.org/wiki/Charging_station

        The term encompasses EVSEs that aren't chargers that work with the car's on-board charger, and DC fast charge units that actually are chargers.

        Europe likes "charging point", but "charging station" is working and winning; Google says

        "charging station" car -> 298,000 hits
        "EVSE" car -> 36,500 hits
        "charging point" car -> 23,700
        • 4 Years Ago
        Still prefer "Charging outlet", similar to "Electrical outlet"
      • 4 Years Ago
      I won't buy any chargers, electric home supply box, plug-in gadgetries, wires, plugs of any sort if it's not fitted with usb ports, wireless data collection and controls to a specialize and didicated informatic programm with support from a website and updates.
      This programm can show you your electric consumption and the electric rate charged by the utility and also if fitted to a windmill and/or solar panel or any other king of free green electricity apparetus then how much electricity you are getting and putting into your plug-in devise. Also these charger box can be wired with the other boxs from neibors and you can control sell or buy electricity in a neibor club
        • 13 Hours Ago
        So you want to pay a lot more for a charging station full of complex software. What will the control panel for all these features look like? How will it decide what to do after talking to your utility or neighbors?

        The trend is in a different direction: you communicate with your car through a web page or a smart phone app, and that web page/app gets electric pricing info from your electric utility to find cheap rates. You use it to tell your car when to start charging. The charging station stays dumb and cheap, and it's a lot easier to upgrade a web page/app than a piece of hardware screwed to your wall.

        Vehicle 2 Grid and community electric sharing are still in early days, though there are a lot of SAE standards in development to support them.
        e85evodude
        • 13 Hours Ago
        So your saying you want a EVSE with smart grid capabilities. There are several of them out there. Not sure about USB abilities though. Windmills and solar panels are better fitted to tie into your home, and not a EVSE as you will most likely be charging at night when solar panels are not doing much.... If your utility is part of the roll-out included in these new smart grids you can track all that stuff. Several of the EVSE's have the will have the ability to charge during off peak times, therefore getting you the cheapest electricity rate to charge your car.
      noevfud
      • 1 Year Ago
      About a year late on this post:)
      • 4 Years Ago
      The most important thing to know about an EVSE? IT'S NOT A CHARGER! That's why they call it "supply equipment" not charging equipment. Please stop calling them "chargers", they don;t charge any more than the Romex in your wall does. It's a charge cord.
        • 4 Years Ago
        Mark, that was one of the main points of this article, that an EVSE is not a charger, and I think Jonas brought that point forward as clear as could be. I fail to see how you could have missed it, Mark.
        • 4 Years Ago
        its not just a charge cord, its a "fancy charge cord".. expect a bunch of adapters start showing up on eBay soon, then use your own ratty extension cord :)
      • 4 Years Ago
      "charge station"? "charge port"?
      • 4 Years Ago
      @Desertstraw,
      Most 120V circuits have a 15A breaker so the charger in the car will automatically draw less. For 240V charging circuits, the breaker range goes from 40A for the Leaf to 90A for the Roadster. The EVSE will communicate the breaker rating to the charger, so it will not draw too much current.

      If you plan to drive the Leaf less than 40 miles per day and only charge at night you should be alright charging it with 120V. Otherwise you would need to charge it longer and if you're on TOU, it would increase your electrical bill.
        • 13 Hours Ago
        @e85evodude ,

        The Leviton Evr-Green charging station will supposedly be available in Q4 2010. As I understand it, the way it finesses the electrical code requirements is you buy a separate "pre-wire kit" ( http://www.leviton.com/OA_HTML/ibeCCtpSctDspRte.jsp?section=33414&minisite=10091 ) that you're supposed to install to comply with the ventilation and height requirements; it consists of a stock NEMA receptacle and a plate. Then the Evr-Green charging station that implements SAE J1772 signaling hangs on the plate and plugs into the receptacle. If you buy the charging station without the pre-wire kit and just plug it into your existing dryer socket... I won't tell anyone ;-)
        e85evodude
        • 4 Years Ago
        No they wont trip a breaker, but you cant just plug your car into the 240 dryer outlet. You can plug into 110 or install a separate 240 charger.

        That being said, There are going to be some plug in 240V EVSE's coming to the market that will allow you to plug into the dryer outlet. But like most of the others out there, they may not be available for quite some time.

        • 4 Years Ago
        @Desertstraw,
        @nottoosmart's explanation is right, but the real reason is National Electrical Code 625 and all its requirements for current signaling, grounding, ventilation (!), and safety interlock. http://www.madkatz.com/ev/nec1999Article625.html

        In Europe, the equivalent "trickle charge" cord will plug into a 230V domestic socket and presumably pull 13 amps max, to halve recharging time. (Europe is lucky, their "public charging station infrastructure" can just be a lot of domestic wall sockets in waterproof boxes.) I find NEC 625 very hard to understand but I think this cord would be in violation of it. I predict there will be a robust semi-underground market in importing this cord and selling it with adapters for various NEMA 240V USA sockets.

        If a car's on-board charger can handle more current, a better solution is a portable charge cord with a control you set to tell the car how much current it can pull from the 240V socket. Tesla sells its Universal Mobile Connector http://www.teslamotors.com/goelectric/charging/universal-mobile-connector , I think it might adjust its current draw according to which NEMA plug you attach.
        • 4 Years Ago
        Plugging a Volt or Leaf into a dryer outlet wouldn't trip a breaker. Both have 3.3kW on-board chargers, which draw only 13.75A. That is much lower than a 35A dryer circuit. Even a 6.6kW charger at 27.5A draw, would still be within limits. Plug in a Roadster and you've got problems.

        Agreed that a 50 or 60A service probably wouldn't be sufficient for 240V charging, depending on regulations.
        e85evodude
        • 4 Years Ago
        What most people dont realize is that installing these is not as easy as tieing the fancy charge cable into the dryer outlet. It will require a much larger breaker in your electrical panel. A lot of people living in condos, appt complexes will not have the ability to install these in their garages as the electrical panel for their unit may only be 50A. Installing these EVSE's will require larger main breakers and possibly larger electrical panels for the house/condo/complex.
      • 4 Years Ago
      I may buy a Nissan Leaf, but there is no way in hell that I will pay over $2000 for the Aerovironment box. I won't pay that as a matter of principle. That is just too much and they are going to stunt the growth of EVs.

      Perhaps I'll pick up the GM one for $490 and install it myself. (Yes, I will get permits & get it approved.)
        • 4 Years Ago
        The box costs ~$700, the rest is installation. Judging from a couple of recent plug-in shows, there's a bunch of J1772 options in the market or soon to be available on the market, so those prices shouldn't hold too long.
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