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Key West HPWC is now on 24/7.

Discussion in 'Florida' started by DavidB, Dec 11, 2014.

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  1. DavidB

    DavidB Aug 2013 S85

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    The HPWC mounted on the side of the Florida Keys Eco-Discovery Center in Key West is now on 24/7.

    The policy change (to leave it on) was established about a week ago, but no one got around to removing the padlock. I'm happy to report that the padlock has been removed. Parking is free, but there is only one charger so please be considerate and move your vehicle after getting charged up!
     
  2. NigelM

    NigelM Recovering Member

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    That's great, thanks David! The site is managed by NOOA and nobody had even informed us at Mote Marine Lab.

    To all those not aware the charger install was paid for by donations from a variety of Florida owners (all members of FTE); any shortfall in power costs is underwritten by me personally through Mote so if you use the charger please consider walking into the Mote Eco-Discovery Center right there and leaving a small donation. Mote is a registered 501c3 organization so donations are tax deductible.
     
  3. Larry Chanin

    Larry Chanin Model S Perf Sig 1055

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    Hi David,

    Thanks very much for this long awaited announcement.

    Can you tell us the source of your information?

    Thanks.

    Larry
     
  4. DavidB

    DavidB Aug 2013 S85

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    I stopped there yesterday to get my car charged up. I was informed by the man who unlocked the charger that the policy had been changed, and that the only reason it was locked was that he hadn't realized that no one else unlocked it!
     
  5. Brit4864

    Brit4864 Member

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    I was there yesterday charging up too and it was unlocked. I remarked to the guys inside about that and they said it was unlocked only because the boss man was away until the end of December. They have done that before when the boss was away so I'm not sure if it really is unlocked 24/7 yet. It would be nice if that is the case.
     
  6. DavidB

    DavidB Aug 2013 S85

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    Wow. I wonder why the different stories?
     
  7. Brit4864

    Brit4864 Member

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    Well now it is on 24/7. I confirmed that today while topping up the charge this afternoon.
     
  8. rjcbox

    rjcbox Member

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    #8 rjcbox, Dec 20, 2014
    Last edited: Dec 20, 2014
    What is the charge rate please?
    29mi/hr if car has single charger, 58mi/hr if car equiped w/ dual chargers?
     
  9. Larry Chanin

    Larry Chanin Model S Perf Sig 1055

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    When the location first opened one of our club members reported a charge rate of 47 mph with dual chargers. With the reduced voltage it is not likely that a single charger could achieve 29 mph.

    Larry
     
  10. Brit4864

    Brit4864 Member

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    I was getting 47-49 the other day. The highest rate I've seen there is 50.
     
  11. Roland

    Roland Member

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    Larry,

    How do you remember all this stuff? I'm amazed.

    Merry Christmas
     
  12. Cottonwood

    Cottonwood Roadster#433, Model S#S37

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    Sounds like 208 Volt commercial, 3-Phase service. 208 is 87% of 240, and 87% of 56 mph is 49 mph charging.

    This is very common. The dual charger cars can accept up to 80 Amps, but the power is Volts times Amps; lower Volts means lower power and lower charge rate. Still, 80 Amps at 208 Volts is MUCH BETTER than 30 Amps at 208 Volts.
     
  13. Larry Chanin

    Larry Chanin Model S Perf Sig 1055

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    #13 Larry Chanin, Dec 21, 2014
    Last edited: Dec 21, 2014
    Yes, but I'm not clear where you got the 56 mph.

    My understanding is that at 240 v at 80 amps the HPWC should charge at up to 58 mph.

    If the commercial 3-phase service starts at a nominal 208 volts it is not uncommon for the voltage under load to be less than 208 volt. On island situations the voltage can drop below 200 volts.

    Here's Roland's first test of the the Key West HPWC. He was probably lucky to get 203 volts.

    Key West HPWC charging rate..png

    Larry
     
  14. Cottonwood

    Cottonwood Roadster#433, Model S#S37

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    It's a fuzzy number. Here are some results from my Sig P85 at 80 Amps. I have a stiff (low resistance) connection at home that starts at 244-245 Volts or so. I have put a current meter on the connection, and when 79 Amps is reported, it is usually 79.9 Amps. I believe that this display truncates rather than rounding.

    80 Amps.PNG

    I have never seen more than 57 mph with this connection, but arguing over a few percent is quite literally "in the noise." For me, the easy numbers to remember at 240 Volts are 56 mph for 80 Amps, 28 mph for 40 Amps, and 21 mph for 30 Amps (all easy multiples of 7 as memory items), then scale everything by actual Voltage.

    You are exactly right that the big issue is 208 vs 240, then significant Voltage sag under load from limp (high resistance) wiring.
     
  15. Larry Chanin

    Larry Chanin Model S Perf Sig 1055

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    I wouldn't say that we are "arguing". I am merely questioning where your quoted 56 mph came from.

    Your home measurements and your conments regarding the truncation of remote application seem to confirm 58 mph for a 240 volt, 80 amp draw.

    The Tesla website consistently mentions 58 amps for 80 amps and 29 amps for 40 amps at 240 volts.

    High Power Charging.jpg

    It wasn't my intent to quibble over a couple of amps, but rather to make sure we were on the same page regarding our basic understanding.

    For me at 240 volts at 80 amps the maximum charge rate is 58 mph. At 240 volts at 40 amps the maximum charge rate is 29 mph (which I occasionally get at home). Originally Tesla quoted the maximum charge rate of an HPWC at 60 mph, but they neglected to say that they were using 250 volts (the allowed upper limit on a nominal 240 volt circuit) at 80 amps for a total output of 20 kW. To avoid misleading their customers regarding the expected charging rate they have since more correctly used the nominal power of 19.2 kW delivered by an HPWC when arriving at the rate.

    For me it is more accurate (and easy to remember) to take the power output in kW and multiply it by 3 to arrive at the approximate maximum charging rate in mph.

    Larry
     
  16. Cottonwood

    Cottonwood Roadster#433, Model S#S37

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    I agree with everything you said. My use of the term argue was only on the friendliest of bases.

    The equation that you stated, MPH = 3 x kW for AC charging is very accurate.

    Just to remind others, MPH = 3.33 x kW for Supercharging, because the approximate 10% loss in AC to DC conversion is inside the Supercharger and the kW reported is all DC into the battery.
     
  17. Brit4864

    Brit4864 Member

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    In the past it was showing 208v but oddly last week it showed 230v yet still only 47-49 ??
     

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