By on October 17, 2012

The SAE unveiled their latest standard for quick-charging electric vehicles and plug-in hybrids that could cut charging times to as short as 20 minutes.

The new standard, called “Combo” combines Level 2 charging (using 220 volts, with a charge time of 3 hours) and Level 3 charging, which should support 480 volts or higher (known as “fast charging”). The ultimate goal for Level 3 charging is that it will take 10 minutes.

The big issue is the rival CHAdeMO standard, supported by Japanese auto makers like Nissan and Mitsubishi.The physical connectors are different shapes, and the “protocols” used to control the charging appliances are not compatible either, so a plug adapter will not allow motorists to use both systems.  Think of the two standards as VHS and Betamax.

While CHAdeMo is in use already on cars like the Mitsubishi i and Nissan Leaf, Combo has the backing of the American and European OEMs. Either way, the consumer has the most exposure to the downside on this one.

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27 Comments on “SAE Approves New EV Charger Standard...”

  • avatar

    I would prefer not to have external access to my car’s CAN bus at every untrusted charging station (which CHAdeMO requires). Nissan is smart enough to use a whole separate bus for the quick-charger in the Leaf, but I just know some automaker is going to just connect that to the car’s main bus and then you’ll be able to do whatever by sending commands from a charger. Sometimes re-using an existing message format is a bad thing, when it’s a hilariously insecure setup like CAN.

    • 0 avatar

      So if I’m reading you right, your worried about somebody maliciously hacking your EV through its charger.

      I can’t imagine when (wasn’t it Bosch?) the CAN bus was developed as a closed system this was on the radar.

      I just read Nissan is hoping to implement steer by wire in as little as a year from now so I suppose your idea has merit, imagine the sorts of a bunch of hackers could have with that.

      • 0 avatar

        “Hacking” is giving it a little too much credit. The CAN bus was originally designed as an internal bus for the components of your car. Anything could send messages along the bus and every node on the bus gets every message and then, on the receiver side, filters out the messages it doesn’t care about.

        There’s no authentication or security built into the standard. Which isn’t a big deal when it’s an air-gapped network that never connects to anything outside the car except maybe an OBD-port reader that you trust.

        (Things go downhill, security-wise, when the CANbus is connected to some wireless transmitter/receiver, such as OnStar)

        If you’re connecting to any random charger, on the other hand, some subset of those chargers may try to inject malicious messages onto the CAN bus. Right now the Leaf uses a separate, isolated bus for the charger, so that the bus that CHAdeMO connects to isn’t connected directly to the main bus that everything else is connected to. That can work. But I’ll guarantee you that some other manufacturer is going to take the lazy route and just connect it to the main bus, and that’s a really bad idea.

    • 0 avatar

      When USB 3.0 just isn’t enough.

  • avatar

    As with VHS and Betamax, the market will decide the winner. In this case, if SAE J1772 charging stations begin to proliferate in the US, the Japanese manufacturers (for whom the US is a key market) may quickly switch to this standard, at least for export models.

    • 0 avatar

      Marketing will come into play if enough of these chargers are set up commercially.

      “Our EV comes the SAE ‘Combo’ plug which means you can recharge as little as 20 minutes on the road at XXX locations. EVs from brand Y cannot. They only have ZZZ locations for a fast charge. If those charges aren’t availabe it could take up to XXX hours to recharge.”

      Show a clip where the SAE charger takes 10 minutes to charge on the road and show another with CHAdeMO with a clock and the changing of the shadows because it takes so long.

    • 0 avatar

      Or the other way around. If a lot of EVs start using CHAdeMO than charge stations may adopt it. Basically it comes down to who brings out and sells the most EVs. Which presently is an uphill battle in any case.

      The issue is that people think of charge stations like gas stations. Which its not, the big difference is that EVs are largely charged at home. Meaning that your home charger may not be the same socket as a charging station, and you may not even to visit a charge station in the entire ownership of a vehicle.

      This is particularly true for cars like the Volt, which have a gas-motor to extend range so that you can just use gas until you get home to your own charger. We should assume then that Volt’s visit charge stations a lot less than Leafs or any other EV.

      What we may end up having is just two different socket standards co-exist, much like how we have different types of phone chargers. Its not ideal but EVs are too niche at the moment and there is little impetus to decide on a single standard.

    • 0 avatar

      It’s worth noting that SAE J1772 is a different animal. The Nissan Leaf, Mitsubishi MiEV, etc all use onboard J1772 chargers (@ ~3kW). Both CHAdeMO and SAE level 3 are offboard chargers that can deliver 50-100 kW to the batteries, or 15-30x faster than existing 15A J1772.

  • avatar

    Is Tesla going to be compatible with this, or is it a completely different system?

    I’d hate to see how expensive that cable is, based on how complex is looks …


    • 0 avatar

      The picture is a CHAdeMO cable. The Combo cable looks like the J1772 cable, only with an extra two high voltage DC connectors on the bottom.

      Tesla uses their own proprietary connector because Elon Musk is a special unique snowflake, or something.

      A note: these fast-charge cables aren’t intended to be installed in your garage any more than a gasoline pump is. (You probably don’t have three-phase power service in a residential zone, for one thing.) For slow-charge everybody is more or less standardized on J1772, except for Tesla (but they provide an adapter, for slow charging at least).

      • 0 avatar

        You could do a DIY single to three phase converter, or spend a few K dollars on a commercial system. But you’d need a pretty big capacity distribution box, too, along with the charger. The costs keep mounting just so you can proudly burn coal in your electro-mobile. (Not that I have anything against coal, but I don’t have any illusions about how clean electric cars really are, either.)

        As to the standards themselves, I like the comment of a very successful engineer/software entrepreneur – God must love standards, He created so many of them.

      • 0 avatar
        Dr. Kenneth Noisewater

        To be fair, J1772 wasn’t terribly common when the Roadster came out..

    • 0 avatar

      Tesla uses the same protocol as J1772 so they can use this with a simple plug adapter. I think the Tesla plug is much more convenient to use than the Combo.

  • avatar

    Nobody, nobody has said that charging a lithium ion battery in 10 minutes is a good idea.

    Nissan already discourages using a Level 3 charger more than once a day, and the Leaf records every charging event to document what the consumer is doing.

    So any hope that such rapid charging is a way to extend daily driving range is in conflict with lithium ion battery technology. Charging a battery isn’t simply a matter of providing a bigger pipe into the electron tank.

    I doubt that my Leaf will ever see a Level 3 charger, let alone be connected to one.

    • 0 avatar

      Hey now, fast charging is the golden goose for other companies like Dewalt!

    • 0 avatar

      Better not tell that to these guys:

      An all-electric bus that charges in 10 minutes, and can be run 24/7.

      Battery technology is evolving quickly.

      • 0 avatar

        1. The Proterra bus looks like it has a fuel cell on board. The traction motor is all-electric. It’s a bit like a Chevy Volt.

        2. They’re charging for 10 minutes every hour. Average speed is reported to be 5-20 miles per hour. This means they’re charging at the rate of 30 to 120 miles per hour. My Leaf’s Level 2 charger does about 17 miles per hour. A Level 3 charger could fill my Leaf at about 94 miles per hour.

        3. So I suspect they’re using a combination of fuel cell powered by a clean fuel, coupled with fast charging, and topping off for 10 minutes every hour. That’s not feasible for a consumer car.

        4. They claim their batteries are ‘chemistry agnostic’. Nowhere do they claim to use lithium ion. For all we know, it could be lead acid, which is very amenable to rapid charging and abuse.

      • 0 avatar

        Actually, the fuel cell is a totally different bus. The primary vehicle that Proterra is selling is a 100% battery-electric vehicle. I have actually ridden on one, and spoken to people responsible for its development. The range is about 40 miles, depending on battery configuration and driving type. The battery chemistry is proprietary, but it is absolutely not lead acid- it is very much a cutting-edge technology. And it can be charged from 10% to 90% battery capacity in 10 minutes with the fast-charge charging station.

    • 0 avatar

      With the exception of the extreme outliers, people don’t drive 80 miles + a day, so most days nobody will need this kind of charger.

      Right now, I travel to Miami about twice a month, totaling 150 miles. So if I used a Leaf or base level Model S to take that trip, I would have to recharge somewhere around the halfway point of the trip to get home.

      Since the electric car is much more economical than the gas, it’s likely I’d want to travel more. So let us say I wanted to go to Miami weekly.

      Would a once a week 10 minute charge harm the battery?

      I would think this would be a reasonable use case for a lot of people since few commute 80 miles plus a day, so most days you could charge up at home and would not need to charge again until you were safely back.


  • avatar

    Well- Toyota is the big dog in this market. Which standard is Toyota going with?

  • avatar
    Robert Schwartz

    “Level 2 charging (using 220 volts, with a charge time of 3 hours)”

    Watts = Volts X Amps.

    The standard household oven line is fused at 30 Amps. In 3 hours, it can delver 19.8 KWh.

    Most BEVs claim 3 to 5 mi per KWh. So, this charge would be for 60 to 100 mi. YMMV.

    “The ultimate goal for Level 3 charging is that it will take 10 minutes.”

    So you will need to increase Amperage or Voltage by a combined factor of 18. The thickest cable at the Lowes is for 660 Volts, so you would need 1800 Amp service.

    Will you need to wear safety equipment while handling stuff like that?

    • 0 avatar

      Again, Level 3 charging is not for your house, it’s for quick-charging stations analogous to gas stations. You’re not going to be buying this stuff at Lowes, any more than the guy running the corner 7-11 is buying a high-flow gasoline pump there.

      And, of course, the customer will be wearing the same safety equipment you currently wear when dispensing your explosive, carcinogenic liquid fuel, i.e. none.

  • avatar

    Whoever wins the standars battle, will manufactures offer conversion kits to the winner? Or do you throw the non-standard car away like I did my Betamax in the 80s?

  • avatar

    Dare you to lick it.

    • 0 avatar

      You could lick that charging connector all you want.

      Part of the standard is a requirement to NOT energize the plug until a signal is received down one of the other wires, to indicate it is plugged in to the vehicle. This would be similar to the way an elevator won’t move unless the door is closed.

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