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J3068 - 3 Phase A/C Charging for North America

Discussion in 'North America' started by quantumslip, Sep 25, 2017.

  1. quantumslip

    quantumslip Member

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    In doing google searches randomly about charging standards, I come to find out this old post on this site:
    What is a J3068 charger?

    That kind of piqued my curiosity and doing a little more digging and looking and some presentations, I found some info about the proposed standard:

    https://epri.azureedge.net/documents/Day%20One%20Presentations%20June2016.pdf (search for J3068).
    j3068specs.PNG j3068.PNG
    The standard is still evolving as far as I know. One change versus the European version seems to be supporting higher 3 phase voltages (for North America) and higher A/C current levels. DC charging is supported ala CCS.

    The main target seems to be for buses and more commercial / industrial EVs, and not so much regular passenger cars. I wonder why such high A/C charging is needed, but there could be various reasons (redundancy, V2G, infrastructure and space).

    Thoughts / feeling on this? In a funny way, we may get a single global connector, but only in certain applications (and even then I wonder about physical connector versus voltage and frequency compatibility). Wonder if any of the more commercial Teslas would use this connector.
     
  2. miimura

    miimura Active Member

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    That would be an improvement over what people are using today. The Smith Electric trucks used by Frito Lay and the Google-Mountain View Community Shuttle electric buses use a rather unwieldy commercial connector. Clipper Creek makes 3-phase versions of the CS-100 that can feed 60kW on-board chargers on these commercial vehicles.

    ClipperCreek for ‘Highest Power’ EVSE | Fleets and Fuels.com
     
  3. SageBrush

    SageBrush 2018: Drain the Sewer

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    Your link says 30 kW
     
  4. quantumslip

    quantumslip Member

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    • Informative x 1
  5. McRat

    McRat Well-Known Member

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    For SAE to skip over support for 277vac and 3-ph operation was a blunder. Their assumption that destination charging would mostly operate at 240 vac was blind to the fact that most commercial and industrial power is 3-ph. Sure, you can charge at 208v, but at a penalty of >13% slower charging at the same peak amps. It should have supported 208 3ph instead, which is 50% more charging at the same peak amps. So a work or destination charger currently is 1/8th less effective when it is fully capable of being 1/2 more effective. Not to mention the unbalance load at the panel when using only 2 legs of a 3ph system

    But the real jump is when they permit 277vac, even at on single phase. 15% faster than 240, but a whopping 3.46:1 faster when used at 3-ph. Or heck, twice as fast when used as 480 2-pole. All assuming the same amps and wire gauges.
     
    • Informative x 1
  6. stopcrazypp

    stopcrazypp Well-Known Member

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    I think the assumption is mainly on home charging. They don't want to increase the costs since close to no home charging would be 3-phase.
     
  7. McRat

    McRat Well-Known Member

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    There are no increased costs by allowing 277v commercial single phase, Tesla engineers knew this. Minor cost increases would occur to accept 3ph like Europe does. 3ph ability does not preclude 1ph 120/240 residential power.
     
  8. stopcrazypp

    stopcrazypp Well-Known Member

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    I'm talking explicitly about 3 phase support. You add two other conductors and the socket/connnector probably costs more too. That adds to unnecessary costs that most people won't use.
     
  9. McRat

    McRat Well-Known Member

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    Europe supports it.
    Most US destination L2 installs are 208 1ph. There is very little cost increase at that point to go 3ph and boost charging rating dramatically at low amps settings.

    But it's too late at this point for the US.
     
  10. miimura

    miimura Active Member

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    Yes, if you connect the Clipper Creek 80 amp 3-phase unit to 120Y208V you only get 30kW. However, it doesn't say what voltages are tolerable on that unit. The Mountain View Shuttles are charged on higher voltage, likely 277Y480V since that is what the on-board charger can take.
     
    • Informative x 1
  11. Cosmacelf

    Cosmacelf Active Member

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    Well, it’ll be interesting to see what the future holds when we starting seeing electric transport trucks. Refrigerated trailers typically plug into 3 phase reefer plugs at the loading docks, so there is already a ready source of 3 phase electricity on some loading docks. I suspect the bigger vehicles are all going to need off board DC charging, though. High current on board charging just means you have to carry around a big heavy cooled rectifier and electronics on each truck. Should be cheaper and more cost effective to place that in stationary locations.
     
  12. quantumslip

    quantumslip Member

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  13. miimura

    miimura Active Member

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    Good find. It's interesting that they want to put 160 amps of AC 3-phase through the standard 62196 (Type-2) 6mm pins. Combining that current with Canadian standard 347Y600V 3-phase power, you get 165kW delivery. Currently, Type-2 is only used up to 63A in Europe, which gives 43kW on 230Y400V power.
     
  14. quantumslip

    quantumslip Member

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    https://epri.azureedge.net/documents/2_SAE_J3068_AC_Charging_October_2017_McLaughlin.pdf

    Another update.

    Something to note:
    • The connector is the european one but the protocol is different. Seems though that you can signal IEC vs SAE so hypothetically one could have European and NA charging with the same vehicle if the vehicle had the HW/SW to support it. Means you can't charge a European Tesla in NA with J3068 out of the box.
      • Don't see Tesla adding J3068 support unless they decide to change the connector for NA
      • CCS DC (type 2) maybe possible out of the box? not clear from the document
      • I could see EVSE bus and truck having support for both if it makes things cheaper supply-chain wise given lower overall volume vs regular cars
        • I do not know how much it would cost to support both in one car, so not sure if future buses and trucks would only support one or both
     
  15. miimura

    miimura Active Member

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    The document lays out a sensible high power AC scheme. The concept of using multiple contactors in the service equipment tied to different voltages is interesting. It does not talk about DC at all. To make a good spec, they should describe the digital signaling for DC using the CCS pins.
     
  16. quantumslip

    quantumslip Member

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    Some of the older presentations mention that they will use CCS DC charging, which already is well documented. Probably will follow euro ccs combo DC. Think it will be only the combo method and not the one just over the type 2 connector.
     
  17. quantumslip

    quantumslip Member

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  18. ka9q

    ka9q Member

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    Single phase 277v (from a 480/277 3-phase commercial supply) would be 277v between the hot phase and ground, while North American single phase "208v" is 120v from each phase to ground. Are you sure the existing connector and associated insulation is rated to withstand > 2x the hot/ground voltage?
     
  19. McRat

    McRat Well-Known Member

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    When you walk into a commercial building usually the lighting is 277vac. This one leg of a 480vac 3ph Wye supply. It is one hot to the neutral. Never to the ground, that's dangerous. Wiring is normally 600v rated. Parking lot and exterior lighting is also 277v, and your AC units and other motors are normally 480v 3ph.

    208vac 3ph Wye is how you get your 120vac outlets in offices. So you have two kinds of voltages in your building normally. You can run 3ph motors with 208, but 480 is cheaper.
     

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