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Supercharger or Mini Supercharger at home ?

Discussion in 'Charging Standards and Infrastructure' started by Kevin Harney, Mar 2, 2015.

  1. Kevin Harney

    Kevin Harney Active Member

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    I posted this question in another thread but did not want to go too far off topic.

    What are the chances that Tesla will produce a Home Super charger or Home Mini Supercharger. Say a Super charger the same as a normal one with 10 chargers or a Mini with 5 chargers that could go DC right into the car ?

    What power requirements would such an animal have and could a typical home handle those requirements ?

    What charging improvements would that allow and would the cost be worth it ?

    Any other thoughts ?

    :confused:
     
  2. RandyS

    RandyS Fan of Elon

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    In San Diego, 3-phase power is not available in residential neighborhoods...As long as the power input is 240VAC single phase, they could design something like this for a home application. The problem as I see it is how much higher than 20 kW can they go to make it more useful than the current HPWC product without causing all sorts of power panel / utility supply issues?

    Maybe a more pertinent question is....What is the driving application that needs more than 58 miles per hour of battery charging at home (provided by the current HPWC)?
     
  3. Saghost

    Saghost Active Member

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    AFAIK the US Supercharger sites are all 480V three phase power (277V L-L) - and I believe European sites use step up transformers to get the same voltage.

    Most residences have 200A service of 240V single phase - meaning that there are only about 48 kW available to the house as a whole. I don't think anything beyond the optional 20kW AC charging makes sense in that context - the car is already taking almost half of the rated power for the house.

    (Some people have 320A or 400A service - usually but not always in the form of two meters. There are also still a lot of homes with 100A service around.)
    Walter
     
  4. Robert.Boston

    Robert.Boston Model S VIN P01536

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    As Randy and Saghost point out, Superchargers draw three-phase 480v power, which is not available to residential customers. And with a draw of 135 kW, using the single-phase power that is available at home isn't tractable: you'd need 600 A service just for the Supercharger. Not happening.

    With the HPWC at 80 A, Tesla has already pushed to the edge of what's practical in the vast majority of homes, which typically have 100 A or 200 A service. And with a 4-hour charging time, I'm really not sure why you'd need anything faster.

    Now, I could see a market for an a DC version of the HPWC, with two inverters. The cost of retrofitting a Model S with a single on-board inverter is higher than buying two inverters. I can also see a market in two-Tesla households, where again it's cheaper to buy the notional DC HPWC rather than paying for twin inverters on both cars.
     
  5. FlasherZ

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

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    That's 277V L-N, not L-L (which is 480VAC).

    The problem that you have with creating such an option is that there will be extremely limited use cases for it. Most people who purchase the HPWC use it for convenience, and most don't *need* the full 80A charging current on it.

    If you somehow have the use case for > 20 kW charging, and you have the funds to pay for the infrastructure and charging unit, CHAdeMO is a reasonable option. Likely CCS in the future.
     
  6. dirkhh

    dirkhh Middle-aged Member

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    And with the HPWC having disappeared from the design studio (and no more dual charger option) even that appears to be going away...
     
  7. Saghost

    Saghost Active Member

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    Interesting. It was there a couple days ago (and still in the tab I had on the page,) but when I refreshed the page it disappeared.

    I seriously doubt that Tesla is permanently moving away from the faster charging, but presumably there's a reason they pulled it out - my guess is that they are making it different somehow and a new version will be back in the order page soon.
    Walter
     
  8. Cosmacelf

    Cosmacelf Active Member

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    From another tmc thread, dual chargers is now going to only be a service center installed option for $2000. Up from $1500 factory, and down from $3600 service center previously.
     
  9. FlasherZ

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

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    Wow...

    Well, I guess I can see a couple of points. I've heard a number of people say that they've ordered the car with HPWC and dual chargers and have found issues with getting the 100A circuit installed, but that seems odd -- punishing those who can because of those who can't isn't the way you solve the issue.

    Hopefully it's just a rework. The online accessories shop still has the wall connector listed for $750.
     
  10. Robert.Boston

    Robert.Boston Model S VIN P01536

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    Interesting, and I can see why Tesla did that: factory install would require a separate "tick" on the assembly line, but only a small fraction of cars actually used that tick. Hence, Tesla can produce all the cars a bit faster. (I also like bringing the retrofit cost down substantially, something I might even take up now that I regularly charge on equipment that can go there.)
     
  11. Zythryn

    Zythryn MS 70D, MX 90D

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    I also wonder how many people actually opted for the dual chargers and HPWC.
    I know a few, however the vast majority I know of don't go that route.
     
  12. dirkhh

    dirkhh Middle-aged Member

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    There was a lively debate a little over a year ago, but searching didn't seem to bring up the correct thread.
    It seems like early adopters (pre SC announcement) and people living in the areas with strong L2 charging infrastructure (the Canadian Electric Hwy plus it's relatives in WA) seemed to mostly have dual chargers, but my guess would be that with the Supercharger rollout and the CHAdeMO announcement (that was going to be available "in three month" for the last year and a half) that ration may have dropped quite a bit... I didn't have it in my S60 and didn't order it for my P85D, either.
     
  13. David99

    David99 Active Member

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    Why fast charging at home? You have all night. Even a single charger (10 kW) is plenty to drive 200 miles every day. If you drive more, you are likely not going home in between, but you are busy on the road. Home chargers don't need to be any faster. Public chargers need to be as fast as possible.
     
  14. AnOutsider

    AnOutsider S532 # XS27

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    This question always pops up, but there's a lot of reasons for quick charging. Coming home and needing to go back out quickly? Or, how about the technology being used for car service businesses?
     
  15. FlasherZ

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

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    I have heard that very few people ordered dual chargers, and it optimizes the line to turn it to a service-center installed option (similar to dealer-installed options in the more traditional world). I understand that he price differential is still an issue, of course. Like the $1200 HPWC, perhaps the price will come down.
     
  16. Killface

    Killface Member

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    What if instead of requiring a ton of power to the home for faster charging, you could get a battery at your house that would store DC power, and be able to quickly dump it into the car. You'd still use a HPWC (or something like it) to convert AC to DC, but you'd be able to dump it into the car at Supercharger speed. This would allow those people with quick turn-around times to charge at high speeds without requiring additional power to the home. We've all heard the rumors that Tesla is trying to put batteries at people's houses.

    Note: I don't think it's likely Tesla's putting much effort into this "problem". I'm with the camp who says 58 miles per hour is already good enough for home charging. I merely present this as a possible solution and hope that someone who actually knows what they're talking about (Cottonwood) will stop by and drop a knowledge bomb on all of us.
     
  17. David99

    David99 Active Member

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    The idea is great. Tesla itself is already doing exactly this at some Superchargers where limiting the power draw from the grid saves them a great amount of money in fees to the power company. But the size of the battery needed for this is significant. You need a battery that is larger than the 85 to be able to recharge your car. It would need it's own dedicated charger as well and then of course the actual supercharger itself. The cost of this entire setup would be significant. Probably as much as a Model S. I doubt many people would buy that.
     
  18. Cottonwood

    Cottonwood Roadster#433, Model S#S37

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    This is exactly what I had hoped Tesla put into their "Mobile" Supercharger, to make installs easier at many sites, but it wasn't so...
     
  19. AnOutsider

    AnOutsider S532 # XS27

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    Maybe once the gigafactory is operational
     
  20. dirkhh

    dirkhh Middle-aged Member

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    It is my understanding that Tesla/SolarCity/Gigafactory are going to work on providing a comprehensive home power solution. From what I heard (and read between the lines) they are thinking about a solution that includes solar panels and a backup battery - either new or possibly reusing older, refurbished packs from Tesla cars (because with a 30% drop in capacity those packs might suck for a car, but they would still be excellent for a home backup).
    Now when you combine THAT with a DC charging solution... that would rock.
    But I wouldn't expect this for quite a few more years.
     

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