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Any possibility of charging on this MRI plug?

Discussion in 'Model S: Battery & Charging' started by Noish, Jul 30, 2015.

  1. Noish

    Noish New Member

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    image1.JPG IMG_3812.JPG
    I live in a remote area of the US (upper peninsula of MI) with minimal charging options. One hospital I work at is 75 miles away from home and I would like to charge there. My options are a 110V AC plug or the above, which is the power source to their previous MRI unit. The hospital had an MRI trailer outside before installing a permanent one inside. It looks like 480 VAC, 3 phase. Is there any way I can charge directly off this? I have a 2015 Model S 70D with a single charger. As far as I understand, this would be an appropriate power source for a supercharger, but is there any way to charge directly off this without changing anything?
     
  2. FlasherZ

    FlasherZ Sig Model S + Sig Model X + Model 3 Resv

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    #2 FlasherZ, Jul 30, 2015
    Last edited: Jul 30, 2015
    That's called a Russellstoll connector. As you note it's a 480/277VAC 3-phase plug that includes neutral. It's used in heavy-duty outdoor locations as a feeder for mobile units.

    Technically, it could work - because Tesla uses both gen 1 and gen 2 chargers in its superchargers with 277VAC (L-N). Imagineer tried his charger with higher voltages (up to 265V, I believe).

    That said, it's most certainly not supported. It's risky in that the charger's tolerance is likely to be minimal for any surges, and you risk destroying your charger(s). There's no way that Tesla would support connecting that to your car.

    Now, let's say we're stranded at your hospital and all 120V/240V is down, and you absolutely *had* to charge. If you were to obtain a proper connector, connect it to a disconnect that provided 50 amp protection, then connect one phase to L1 of the 14-50, neutral to the L2 of the 14-50, and ground to ground, it may work. :) My way of saying "I think you're out of luck, but if you're the risky type..."

    You'd need to label that thing 6 ways to Sunday because any other application that tried to use that connector (an RV, for example) is likely to experience anything from improper operation to destruction of equipment.
     
  3. Rocky_H

    Rocky_H Member

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    Wow. I am always fascinated with new outlet types, and that’s a good one. It is a 3 phase one, which you can’t use natively. The chargers in the European spec Model S are set up to use 3 phase because it is more common there, but the chargers in the North America spec cars will not take 3 phase. I don’t quite know if there is some kind of adapter cable that can make a usable 2 phase from that, but I still think the voltage level would be too high for what the charging system is willing to take.
     
  4. FlasherZ

    FlasherZ Sig Model S + Sig Model X + Model 3 Resv

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    It's a 480/277Y connector. Line-to-neutral is 277V, which is what they use in the supercharger, so in theory it could work. As mentioned, in practice, it's definitely not going to be supported by Tesla.
     
  5. mknox

    mknox Well-Known Member

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    Interesting. I hadn't twigged to the fact that the bank of chargers in the Supercharger were supplied at 277 volts. I had just assumed there was some sort of step-down to 240 or 208 volts going on there. Are we sure the charger units in the Supercharger are exactly the same as the ones in the cars?
     
  6. FlasherZ

    FlasherZ Sig Model S + Sig Model X + Model 3 Resv

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    Those are "optional" pins that can be used for contactors, shunts, etc. Their use is application-specific.

    - - - Updated - - -

    There are some pictures floating around of the modules in the cabinets and they do indeed appear to be the same. Original voltage specs listed were 85-265VAC for first-gen, 300VAC is limit for second-gen, but indeed Tesla has said several times they use the same chargers as in the car to keep their costs down.

    Tesla first-gen superchargers show specs for 480/277Y and 240 VAC connections (delta). L-N (wye) is required for 400-480VAC.
     
  7. Cosmacelf

    Cosmacelf Active Member

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    Gosh, I'd be sorely tempted to build myself a contraption like FlasherZ outlined - find a matching plug, feed the correct wires into a small breaker box to accommodate a 50 amp breaker and then feed that into a NEMA 14-50 outlet.
     
  8. Ingineer

    Ingineer Electrical Engineer

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    No! Do not do this! While the charger in your car is rated to either 277v (Gen1) or 300v (Gen2), the UMC most definitely is NOT!

    There are MOVs (Metal Oxide Varistors) inside that could short out and destroy your UMC. The main filter cap may also not have enough dielectric headroom and could explode if breakdown occurs due to overvoltage.

    To do this safely, you'd need to construct (or modify) an EVSE that can operate at 277v.

    I can confirm that a Gen2 charger will safely accept higher voltages (up to 300v) and charge slightly faster because of this, but I do not recommend anyone attempt it, the slight increase is not worth the added danger.

    When charging on 240v, your maximum voltage over ground anywhere is only 120v, whereas if you use 480v wye on one leg, you have 277v over ground on one side which is a lot more dangerous!

    If you must do it, purchase a 10kva rated 480v to 240v transformer and make up a proper rig and cable set. Then you'll be doing it safely.
     

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