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Anyone Charge from 277 VAC Single Phase? HPWC manual says its OK...

Discussion in 'Model S' started by HPEV, Jul 1, 2016.

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  1. HPEV

    HPEV Member

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    I see on Tesla's website that the HPWC unit has been redesigned and is even cheaper now. Page 5 of the manual states at the top, "The maximum power rating for the Wall Connector is 20 kW or 80A at 250V AC single-phase power. Your vehicle can charge from 200V to 277V single-phase power."

    It just so happens I am looking at getting one of these units for workplace charging and they are putting in a new transformer for the charging station. The place currently has 208 VAC power and since they were putting in a new transformer I asked whether it could be 240 VAC instead of 208 since that'd give the EVs charging more watts.

    For this location the electrician said it would be far cheaper for him to provide single phase 208 VAC or single phase 277 VAC to the HPWC. I have been a long-time EV owner and am very familiar with how much quicker charging is on 240VAC (or even in some cases at RV parks where I've seen 250 VAC displayed) compared with 208VAC due to the increased total watts when multiplied by the higher voltage.

    I have never personally encountered or charged from 277VAC single-phase and wasn't honestly aware of it or that the car could charge from it but it says it's okay right in the new HPWC manual!

    My question is has anyone here actually charged from 277VAC with their Tesla?

    Also, 80 Amps * 277 V = 22,160 kW That is greater than the 20kW the car says it is capable of so I'm curious if the car actually can do 22,160 watts or if it cuts back the amperage at 277VAC so as not to exceed 20kW?

    80A of 208 V = only 16,640 watts so there is a substantial difference of 5.5kW between those options which would lead me to have them wire it for the 277VAC but I'm wondering what other people's experience has been or if it is limited to 20kW anyway?
     
  2. oneday

    oneday Member

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    Can't answer any of your questions for sure, but it appears that at least one other person has done this Thank you to all the engineers who made design decisions on the High Power Wall Charger

    I would guess that your speculation on gaining more wattage from the 277v line would be correct however. Limited by the amperage that your charger in your car is capable of. Do you have the new 75amp charger? If so, I would suspect you would get 75x277 at peak charging. The question that I would want to ask Tesla is if all previous cars built in chargers are capable of charging at 277v it would be a shame to plug in a friends vintage model s and have some issues.
     
  3. scaesare

    scaesare Active Member

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    A few folks have reported doing it. It does appear to cut back the current in order to stick to the 10KW/charger limit.

    The chargers in the car are the same used in supercharger cabinets, which more often than not are fed 277V. The power cutback is likely to protect the rest of the components, I suspect.

    I'd definitely do it in your situation if it's financially feasible.
     
  4. araxara

    araxara S-P85#3,218 X-90D#3,299

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    • Informative x 1
  5. HPEV

    HPEV Member

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    Thank you Araxara for that link!! That confirms that it is indeed possible for a Tesla to charge from level 2 charging at 22kW if it is being fed 277 VAC single-phase and it is a Tesla capable of 80A charging and if the HPWC is the new version capable of handling the 277VAC!

    Nothing like an actual photograph of the screen to prove it and that is exactly the information I wanted to know! Very cool!
     
  6. Humanji

    Humanji Member

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    I've done it. Works fine! Amps will be slightly lower due to the higher voltage (same kW). My p90d refresh shows 72A when charging at home in 220, but 67A at work where I put in a hpwc on 277 single phase feed.
     
  7. Humanji

    Humanji Member

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    I'll take a picture and post next week
     
  8. oneday

    oneday Member

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    220v @ 72 amps =15.8kw
    277v @ 67 amps =18.5kw
    Seems like the 277 will provide a faster rate of charge.
    Even if the voltage was 240v it would still be less than the 277v @ 67 amps
     

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