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HPWC at 80 amps only getting 55 MPH not published 62 MPH

Discussion in 'Model S: Battery & Charging' started by Jdcleary, Jul 31, 2013.

  1. Jdcleary

    Jdcleary Member

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    Disappointing results today when new fuses installed in HPWC only provided 55 MPH.
    Disappointing Results.jpg

    Has anyone been able to get the published 62 MPH?
     
  2. gmontem

    gmontem Model S P01707

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    Is your range expressed in rated or ideal miles?
    Sent from my Nokia Lumia 920 using Board Express
     
  3. Jdcleary

    Jdcleary Member

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    Rated. Started charging at 169 rated miles and took picture when it reached 201 rated miles. Started charging at about 48 mph and slowly, very slowly, went up to 49, 50 51, etc. Finally, at the maximum rate of 55 and completing the standard charge at 55 mph.
     
  4. steve841

    steve841 Active Member

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    My simpleton theory is just like cell phone ads. ..... 80hrs talk time. Never seen that...

    I'm sure that's lab testing under near perfect conditions...
     
  5. NOLA_Mike

    NOLA_Mike Active Member

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    Yep - your voltage has dropped to 231V. The only way you would stand a chance of getting 62 is at 80A and 250V.
     
  6. FlasherZ

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

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    I can get 60 rmphc @ 245V/79A. 231V/79A (18.25 kW) will get you only about 91% of the 20 kW value of 62.
     
  7. mitch672

    mitch672 Active Member

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    That's a theoretical maximum at 250V 80A, in reality none of us have 250V. My energy supplier replaced my electrical service today.
    I was getting 238V under no load, when my OpenEVSE was running at 75A, the voltage dropped to 213-215V. Today a dedicated 50KVA transformer was installed, just to my house at the pole (they in fact installed a new pole as well).
    I am now getting 50 miles/hour, and at 75A, the voltage is still 238V under no load, and only drops to 225-226V now under load.. My meter is still 200 feet from the pole, so some of the voltage drop is wire resistance. See the iPhone app screenshot below:

    image.jpg
     
  8. AC1K

    AC1K Member

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    your utility or something in between is dropping too much voltage, the HPWC isnt getting enough juice to charge at its designed limit.

    this happens when there is resistance in the line, the line is too long, the line has crappy contacts, or the grid is under a heavier load,

    you will see better results if you use cables that are "overkill" for example, my subpanel gets power from the main breaker via 100A breaker, i used a 125A cable to go to the subpanel. I then have a 50A breaker going to the NEMA 14-50, but the cable supplying the power is rated for 65A.

    all the connections are coated with conductive grease and tightened properly

    Screenshot_2013-07-23-21-27-53.png

    when i charge at 20A i get 245v (forgot to take a screen shot, ill get one later)
     
  9. FlasherZ

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

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    It could be any number of things, and beyond using 12 AWG on 20A circuits, you don't have to worry too much about the ampacity of the wiring that you're using, as long as you're following the NEC rules.

    The OP doesn't have a far out of spec voltage. My guess is that it starts at about 235-238V and drops to 231V under that load, which is completely normal. Even going up to 2/0 conductors won't gain you much back, maybe 2-3V at best. OP: what's your voltage when the car shows it's drawing 0A (right after you plug in)?

    There are only three things you can do:

    1. Ask the power company to check the distribution/transformer voltage. If you're getting 235V or more at the service panel, though, you're likely to hear that they're within spec. That said, one time my PoCo was presenting only 231V or so and they replaced a component, and it jumped up to 248V.
    2. Live with it. :)
    3. Source a 100A, 5% boost transformer. I'm roughly guessing this is likely to cost you a few thousand dollars and you'll have to ask whether that 5 mi/hr is that critical.
     
  10. brianman

    brianman Burrito Founder

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    Some of us don't even have our fuses yet and people are already complaining that their new 80A-compatible fuses aren't enough.

    Maybe I should start an Sig HPWC Legacy Fuses Angst thread.
     
  11. deonb

    deonb Active Member

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    The stated web site number of 62mph is ideal. Which is 55mph rated.

    I bet you'll see the 62mph number if you switch to ideal.
     
  12. William13

    William13 Member

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    I have seen 246V with 80A. I have new everything and very thick wire to the HPC. I have required fast turn around times 4 times so far. The fuses have worked so far. Otherwise I charge at 30 A. I never see a voltage drop under load.
    Thick wires and oversized supply.
     
  13. Galve2000

    Galve2000 Member

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    55 miles of range per hour of charge is still pretty fast... you can fully charge a nearly depleted MS 85 in about 4.5 hours.. i know, i know.. not great for road trips... but in real life (at least to this forum contributor) pretty AMAZING.
     
  14. montgom626

    montgom626 Active Member

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    What gauge and length of the wire going to your HPWC?

    Just a few curiosity questions.
    1) What gauge is the wire going to your HPWC? 6? 4?
    2) How long of a run is the wire in #1 from the breaker box to the HPWC.

    - - - Updated - - -

    And a short wire run helps too! :)
     
  15. Lloyd

    Lloyd Active Member

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    You should have #3 minimum for 80 amps (continuous) with any length of run. #3 is hard to find and expensive so I opted for #2.
     
  16. mitch672

    mitch672 Active Member

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    StayOnline has #3 THHN for .75 per foot, the issue with them is, they only ship via FedEx, so even with FedEx Ground, you can be talking about more for shipping than wire. I did buy 25' of Red/Black #6 THHN from them for my install (had #6 Green THHN for the ground already)

    600 Volt THHN
     
  17. Jdcleary

    Jdcleary Member

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    My apologies, switching to ideal miles does produce 62 mph. Thanks for all your comments. picture161.jpg
    You need to follow up on why you don’t have your fuses. My selfish interest was to reduce the time I bothered all my Tesla friends when stopping to use their HPWC. Let’s get some Super Chargers in the mid-section of the country.
    You are right about “pretty AMAZING” but when travelling Tesla owners stop by me, I want to give them maximum mph. Not that I want them on their way, :smile: but just to reduce their charge time
     
  18. brianman

    brianman Burrito Founder

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    They didn't arrive on their own. Tesla hasn't called. And life has been busy. I'll go into nag mode soon enough. ;)
     
  19. Lloyd

    Lloyd Active Member

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    I called again on monday, and asked about my updated fuses and assembly. The person on the phone said I had to drive to the service center to pick them up, and they did not have any anyway. I said that I was a 4 hour drive away, and they should mail them or have one of the rangers drop them by when they are in the area. The person said that it was not their policy to ship parts. I said that does not sound right and he should check again.

    Yesterday I got a call. Fuses are in, and I was correct, they could be mailed. I had to verbally certify that I had an electrician to install the parts.
     
  20. PhilBa

    PhilBa Active Member

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    Don't you just love it when you know more about company policy than the guys that work there?! I still am amazed by the power that the internet places in the hands of us consumers.
     

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