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Charging on 230V/14A

Discussion in 'Model S: Battery & Charging' started by AlbertF, Apr 5, 2016.

  1. AlbertF

    AlbertF Member

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    Hi,
    maybe it's just a stupid newbie question, but I have no option to install something else in my garage, as this standard Europe 230V/13-14A already in place.
    Just read in the "owning model S" that charging on standard 110V in US would be an absolute nonsense, because of appr 65% effectivity. So ccharging 1 KWh would consume appr. 1,54 kWh. This can sum up pretty ugly.
    Is it than ineffective on 230V too? Or is it not so dramatic?
    I have a public charger some 50 meters away from my home. Is it ultimately a better option?

    Any hint is highly appreciated. And uhmm...sorry for my English, I am a kraut )))
     
  2. brkaus

    brkaus Member

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    230v / 14a should be significantly better than 120v.
     
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  3. Edmond

    Edmond Permanon

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    Yes 230V is actually a better system than we have in the US. Uses less copper as, higher V means less A.

    The Tesla charging equipment works great in the EU.

    PS - Wish I lived there...
     
  4. AlbertF

    AlbertF Member

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    Wow! That sounds great!
    As for charging infrastructure, they build Supechargers only on freeway (Autobahn) junctions, so the nearest from me will be some 100 miles away. And I live in Stuttgart, the city of Mercedes, Bosch and Porsche...
     
  5. maghielma

    maghielma New Member

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    Hi from Bergamo, Italy. I use to charge my Model S 70D at home during night. I limit the max ampere to 15 that means 3,3 Kwatt at 220V. I keep the rest of my 6 Kw for home charges. At that given amper I can charge 15 Km/h just enough for my daily trips. If necessary I can double the ampers if house consumption allows it. Ciao
     
  6. maghielma

    maghielma New Member

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    Right now !
     

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  7. AlbertF

    AlbertF Member

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    I get some 13-14 km/h, which is perfect for my consumption profile. My warry was rather about the overhead, since I cannot tell if the car consumes way more than gets finally into the battery....
     
  8. Rocky_H

    Rocky_H Member

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    Hey, Albert. The inefficiency because of the overhead comes from the low total power level, not either the voltage or amperage specifically. A 120V 15A circuit in the U.S. will be using 12A to the car. (That’s an electric code requirement in the U.S., 80% of the circuit rating for continuous loads.) That 120V times 12A is 1,440 W. That’s just not very much power. I don’t know how much it is exactly, but just having the charging hardware active and running during a charging cycle consumes somewhere near 400 W. So that is where about 1/3 of the total power is getting lost, just running the charging system. So in any charging level with higher power, that 400 W is still being wasted, but it’s a smaller and smaller percentage of your input power, meaning more efficiency. So at the 230V 14A you are talking about, that would be 3,220 W, minus 400 W, is 2,820 W. That’s an efficiency of about 88%.
     
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  9. Cyclone

    Cyclone Active Member

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    While I was unaware of the "400 W overhead" of running the charging equipment that @Rocky_H mentioned, but I was basically going to say the same thing. There is a fixed overhead for charging, which is a much larger percentage of 120v @ any amperage than 2xx volts @ any amperage.
     
  10. AlbertF

    AlbertF Member

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    @Rocky_H : Well, this way out it is a reasonable calculation basis. I assume, those 400W would vary, depending on outside temperature and stuff like that. Has anybody ever conducted some sort measurement series? And, btw, where do the 400W come from? Is it somewhere in Tesla sources?
     
  11. Rocky_H

    Rocky_H Member

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    It’s certainly not from Tesla officially, and I don’t have a reference I can point to for that, because I just remember seeing it here on this forum some time ago. Like I said, the 400W is a pretty vague approximation—could be more or less than that—don’t remember. That’s mainly from running the charging system in the car, so I don’t know if it would be very temperature dependent. The way someone got that number is from seeing the charging rate differences from various power levels.


    Basically here is how people saw it: It’s most obvious at lower power levels because it’s such a big portion of the power being lost. Start with the lowest power level we can charge with here in the U.S. That’s 120V and 12A. If you can get to 120V sources at 16 or 24 amps, the energy into the battery goes up a lot more than the increase in current. Once you’re up into several kilowatts, though, it is insignificant and not really worth mentioning.


    Temperature does affect the charging rate from a separate mechanism, though, and can be a much bigger effect, if the car is needing to divert some of the incoming energy to run the heater in the battery pack to warm it up enough to charge. On that 120V 12A I mentioned before, some people have seen really really cold outside temperatures overnight, where it was using up almost all of that energy just for heating and couldn’t really spare much to put anything into the battery, so it got hardly any range added overnight. Even on some 240V low amp sources, this can greatly slow down charging, as it adds no miles for the first 10, 15, 20 minutes, just warming the battery, before it starts to add range.
     
  12. AlbertF

    AlbertF Member

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    Well, thank you so much, it was a very comprehansive explanation.
    Now I know, what I am on. It would be not bad, if Tesla would consider this fact in their model savings calculation on the front page :)
    This is what I encountered from this forum way after I got my Model S :)
     
  13. AlbertF

    AlbertF Member

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    To be honest, it would change my mind though...
     

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