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80A to 72A downgrade

Discussion in 'Model S: Battery & Charging' started by brianman, Apr 12, 2016.

  1. brianman

    brianman Burrito Founder

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    I was only half paying attention when the Model X 48/72A charger situation developed.

    Now that it's the "upgrade" for the Model S...

    What's the rationale for downgrading the max home and destination charging rate on the Model S and X?
     
  2. _TTT_

    _TTT_ Member

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    I talked to a Tesla employee in December of last year and he mentioned that they wanted to standardize on a single charger solution across the fleet.
     
  3. markb1

    markb1 Active Member

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    Maybe it saves Tesla money? Now the 72A option only required one charger, not two?
     
  4. brianman

    brianman Burrito Founder

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    That explains why S is getting it, and was what I suspected. But why did X get a lesser (IMO) configuration than the original S?
     
  5. brianman

    brianman Burrito Founder

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    My impression was that the S had 40 or 40+40, while the X has (24+24) or (24+24)+24. In more English that means 1-2 chargers for S and 2-3 chargers for X. More units but "smaller" units.

    Not clear to me how that saves Tesla (or customers) money.
     
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  6. neroden

    neroden Happy Model S Owner

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    Oh, I bet it's thinner gauge copper wire in each unit. More of it (since they're paralleling) but thinner gauge; easier to work with and probably cheaper. Also all the inverter parts can be sized for lower amperage since they're spreading the load in parallel amongst more inverters.
     
  7. omarsultan

    omarsultan Active Member

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    After chatting with a Tesla employee a while back, I was left with the impression that its a single charger that is either 48A or 72A, which is why you cannot upgrade after the fact like you could going from 40A to 80A.
     
  8. Twiglett

    Twiglett Single pedal driver

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    Two quick facts to check.
    1. The old chargers were 40A
    2. The same chargers were used in superchargers
    Would that imply that we may soon start seeing superchargers that are based on the new either 48A or 72A units?
     
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  9. TaoJones

    TaoJones Beyond Driven

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    The onboard chargers are unrelated to supercharging.
     
  10. gaswalla

    gaswalla P4201/85/airsusp/pano/19i

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    Not true Tao.
    Simple understanding- an individual car's chargers are irrelevant in supercharging because it is DC charging

    Next level of understanding - tesla superchargers use a series of chargers to generate the DC current. Improving the Chargers may imply higher kW charging on superchargers in the future.
     
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  11. Twiglett

    Twiglett Single pedal driver

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    obviously the one IN THE CAR are not used for supercharging - but that isn't what I said at all.
    The question was to clarify something that has been mentioned many times, that the same charger design is also used superchargers (to clarify - in the SC cabinet, not the red/white pedestal)
    I thought the cabinet was a stack of the same charger designs.
    Meaning that maybe Tesla could be planning higher capacity SCs
     
  12. Twiglett

    Twiglett Single pedal driver

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    Thanks Gaswalla - that is exactly how I understood it too
     
  13. Twiglett

    Twiglett Single pedal driver

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    which could imply that they could continue the design change and increase SC charge rate by 20% with the 48A units or even higher with the 72A boxes.
    Or maybe just fewer to get the same capacity, which would reduce the cost of each SC
     
  14. bxr140

    bxr140 Member

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    Cost to tesla for 48v vs 72v is likely fractions of a percent...
     
  15. TaoJones

    TaoJones Beyond Driven

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    I sit corrected, gentlemen - thanks. Will search for supercharger design threads to attempt enlightenment.
     
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  16. brkaus

    brkaus Member

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    This is also my impression. One can get 72A in a single unit. Lower cost, less weight.

    And the dual solution didn't really add redundancy as the master had to function for the slave to work. So no benefit there.

    It probably comes down to something simple. Maybe the X could only fit one charger. Probably even more so for the 3. 72A was the best they could get in the space. Saves money to keep product line parts the same. With most getting the 40 before, the vast majority gets an upgrade to 48.

    Probably will end up in the supercharges as well someday. Just to keep the part count down.
     
  17. Razlak

    Razlak Member

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    The new wall connector also says it can run at 277V for commercial installations, and 277V*72A is still about 20kW charging. So hopefully new commercial installs will put them on their 277/480V panels. It will also be interesting to see if the old chargers will do 11/22kW (277V*40/80A), or just limit down to 10/20kW still.
     
  18. Paul Carter

    Paul Carter Active Member

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    I don't get it either. I'd rather see it climb to 125 amp (100 continuous). Maybe this is such an edge case its not viable/desired by most customers. I guess we might as well go to the nearest DCFC or Supercharger (or stay there longer rather) if quick destination charging isn't going to cut it.
     
  19. wraithnot

    wraithnot Model S VIN #5785

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    This was the situation in 2012:

    "The Supercharger is clever in its construction. It starts with the same 10-kilowatt charger that is onboard every Model S. To build the Supercharger, the company strings together 12 of the same units, which were designed from the beginning as building blocks.

    “It’s good modular engineering,” Mr. Straubel said. “We configured all the circuitry, the power and the communications so we can just stack them up.”

    http://mobile.nytimes.com/2012/09/30/automobiles/on-an-electric-highway-charging-into-the-future.html?referer=
     
  20. FlasherZ

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

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    The story on Model X is that Tesla wanted to go with a single charger to eliminate all the software complexity and hardware complexity associated with having to manage dual chargers, along with eliminating various failure scenarios across two units.

    Note that the 72A charger isn't really a 72A charger, either, at higher voltages. It's limited to 17.5 kW -- at higher voltages the car will scale back the current. For example, at my 250V, the car typically charges only at 69A or so.

    I've heard rumors that the charging team at Tesla believes that with Supercharging capability being rolled out more densely, the AC charging is only needed for overnight and 48A is fine for that. That helps Tesla with problems related to high heat while charging at 80A.

    With Model X this turned into a giant hullabaloo as Tesla announced the car would only have 48A charging, then reverted back to a 72A hidden option, and is now offered as a general option.

    I disagree with that thought process -- I want fast charging. But that's the reasoning I've heard.
     
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