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Why is MX Charging Rate Slower Than MS and M3?

Discussion in 'Model X: Battery & Charging' started by BnBinAlpine, Aug 22, 2018.

  1. BnBinAlpine

    BnBinAlpine Member

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    DED35364-9CA4-4E5A-9035-087D35C6A12E.png Does anyone know the technical reason why the Model X charging rate for all types of connectors is less than both Model S and 3 (though I realize the 3 is a different architecture)? See attached photo from Tesla’s Shop-Charging page.
     
  2. animorph

    animorph Active Member

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    In terms of miles/kWh the X is the least efficient of all. So the same charge rate results in fewer miles added per hour.
     
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  3. MP3Mike

    MP3Mike Well-Known Member

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    Because it is bigger, heavier, and has a higher cD. Therefore it has to use more energy to move the vehicle the same distance.
     
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  4. BnBinAlpine

    BnBinAlpine Member

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    But you’re talking about USAGE of the 2 vehicles. Let’s say you took both batteries and their onboard charge controllers out of an S and X. When you plug them in to Charge the battery, if the hardware and software are the same (for charging) why wouldn’t they charge at the same rate?
     
  5. tpham07

    tpham07 Active Member

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    technically it charges at the same rate.

    However the amount of energy a model X needs to propel it the same distance as a Model S is more, and even more for a model 3. But you're still charging at the same rates. So you're adding the same amount of energy, just less "miles equivalent" of that energy cuz the model x uses more...if that makes sense hah.

    Charge rate is measured by Volts and Amps. (kw).

    Mi/Hr is not a measurement of charge rate, it is just an approximation so people can quantify how fast they're charging because obviously not everyone understands Volts/Amps.

    If you plug a Model S & X into a supercharger, and they both read 102kw, then they are charging at the same rate. One will have a different mi/hr measurement than the other though, because that is based on the wh/mi formula, and a model x uses more wh/mi than a model s.
     
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  6. MP3Mike

    MP3Mike Well-Known Member

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    You aren't adding miles to the battery, you are adding energy. If you want a miles per minute metric you have to do the calculation to convert the energy into miles which will be different based on the energy needs of the given vehicle.

    It is the same as what happens at a gas pump. Say the pump delivers 5 gallons per minute. If you drive a Prius that gets 50 MPG you add 250 miles per minute of pumping. On the other hand if you drive a Ford Excursion that gets 10 MPG you only add 50 miles per minute of pumping. In both cases you put exactly the same amount of energy in per minute.
     
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  7. BnBinAlpine

    BnBinAlpine Member

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    Ok, got it now, thanks all. I looked further on Tesla's website and found that both the S and X do come with the same onboard charger -

    Per website:
    For new Tesla vehicles, the on-board charger capacity is matched to the the vehicle battery:

    Vehicle battery option On-board charger capacity (current/power)
    Model 3 Standard battery 32 amp / 7.7 kW
    Model 3 Long Range or Model S or Model X with 75 kWh battery 48 amp / 11.5 kW
    Model S or Model X with 100 kWh battery 72 amp / 17.3 kW
     
  8. Rocky_H

    Rocky_H Active Member

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    The explanations sound complicated, but here's a really simple analogy to be able to instinctively see the difference like a light bulb moment.

    Let's say you are filling a Ford F-350 pickup truck and a Ford Fiesta subcompact car at the same gas pump. The pump is supplying some flow rate of gallons per minute. The same rate of fuel is going into both vehicles at the same rate, right? But the Fiesta is getting a lot more "miles" per minute, because each of those gallons gives it a lot more distance. So the efficiency ratings of like 20 mpg for the truck and 40 mpg for the small car directly related to the "miles per minute" filling rate.
     
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  9. BnBinAlpine

    BnBinAlpine Member

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    Yes, the light finally went on when I realized the rate Tesla was listing wasn’t how many electrons were being added per hour but rather the range of each type of vehicle those electrons would provide. Your analogy is great, thanks.

    In the meantime, really can’t get enough of driving the X, an amazing vehicle!
     
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