TMC is an independent, primarily volunteer organization that relies on ad revenue to cover its operating costs. Please consider whitelisting TMC on your ad blocker and becoming a Supporting Member. For more info: Support TMC
  1. TMC is currently READ ONLY.
    Click here for more info.

Electrify America Fast Chargers - Huh?

Discussion in 'Supercharging & Charging Infrastructure' started by minderbinder, Oct 29, 2018.

  1. more863-also

    more863-also Member

    Joined:
    Aug 6, 2018
    Messages:
    260
    Location:
    Colorado Springs, CO
    I guess saving five minutes on a road trip, the only time you should really SC anyways, isn't that attractive to me.
     
    • Like x 1
  2. ItsNotAboutTheMoney

    ItsNotAboutTheMoney Well-Known Member

    Joined:
    Jul 12, 2012
    Messages:
    10,212
    Location:
    Maine
    When you arrive at a location would you like to plug in straight away or wait 5 minutes?

    Besides reduced charging time, you also have increased capacity per stall, and reduced waiting time.

    It's good in multiple ways.
     
    • Informative x 1
    • Like x 1
  3. more863-also

    more863-also Member

    Joined:
    Aug 6, 2018
    Messages:
    260
    Location:
    Colorado Springs, CO
    What does waiting time have to do with it? Many people, especially apartment dwellers that must rely on SCs only, charge to at least 90 percent. Total time of charge is barely affected since the envelope of full speed charging is so small.

    This is in addition to the fact that Tesla has started implemementing time limits at some SCs, often 40 minutes. So another check against "more likely to not have to wait".

    What does "increased capacity per stall' mean?
     
  4. MorrisonHiker

    MorrisonHiker S 100D 2021.4.11

    Joined:
    Mar 8, 2015
    Messages:
    9,151
    Location:
    Colorado
    I think he's referring to queue theory. That 5 minutes might not sound like a lot but when things get busy, the line can grow and really cause a backlog. By shaving just a few minutes off a charge, they can increase the number of charges each stall can handle per hour.
     
    • Like x 1
  5. more863-also

    more863-also Member

    Joined:
    Aug 6, 2018
    Messages:
    260
    Location:
    Colorado Springs, CO
    If only 20 percent of stalls are capable of that charge, and only a tiny proportion of CCS cars can charge at that rate, then it's likely those cars that can charge that fast will often have to occupy slower stalls, or wait for the faster stalls specifically. The argument for this approach actually gets weaker the more congested the station is, as it becomes more unlikely that 350kW vehicles can charge at a 350kW stall. It's much more complex than basic queue theory.

    This is to say nothing of the fact that those stalls are more expensive, and that another "only" 150kW stall would be more useful.
     
    • Informative x 2
  6. ItsNotAboutTheMoney

    ItsNotAboutTheMoney Well-Known Member

    Joined:
    Jul 12, 2012
    Messages:
    10,212
    Location:
    Maine
    Yes.

    While people currently are concerned about coverage, capacity is the real challenge for EVs. More capacity required means either more locations or more chargers in a single location. We know how time-consuming securing suitable locations can be, and that some sites are limited in the number of stalls they can support.

    Faster charging helps the charging driver, helps the approaching driver and helps Tesla.
     
    • Like x 3
  7. ItsNotAboutTheMoney

    ItsNotAboutTheMoney Well-Known Member

    Joined:
    Jul 12, 2012
    Messages:
    10,212
    Location:
    Maine
    They would just have to make the 350kW chargers cost more. (If they aren't more expensive, they might as well all be 350kW chargers, even if a site has a limited total capacity.) If they cost more, people with slow-charging cars would go to the cheaper chargers.
     
  8. more863-also

    more863-also Member

    Joined:
    Aug 6, 2018
    Messages:
    260
    Location:
    Colorado Springs, CO
    That would be an option. Then they'd probably need to charge Leafs charging at 35-45kW even less, but then again, the whole point of the operation is to rip off EV owners with slow DC charging.
     
  9. ℬête Noire

    ℬête Noire Active Member

    Joined:
    Jan 30, 2018
    Messages:
    3,105
    Location:
    TX
    #89 ℬête Noire, Dec 7, 2018
    Last edited: Dec 7, 2018
    The actual peak in practice is lower, yeah. However the the 90 miles in 30 min is real and confirmed (but not directly by me because I didn't bother with the DCFast). On the >50kW charger you'll see more like 100mi starting from a low SOC.
     
    • Informative x 1
  10. more863-also

    more863-also Member

    Joined:
    Aug 6, 2018
    Messages:
    260
    Location:
    Colorado Springs, CO
    How many miles per kWh does a Bolt get? 100 miles seems optimistic at 50kW.
     
  11. ItsNotAboutTheMoney

    ItsNotAboutTheMoney Well-Known Member

    Joined:
    Jul 12, 2012
    Messages:
    10,212
    Location:
    Maine
    They say 90 miles in 30 minutes.

    90miles/55kW*0.5h = 3.27 miles/kWh.
    90miles/50kW*0.5h = 3.6miles/kWh
    90miles/45kW*0.5h = 4 miles/kWh.

    Bolt EPA Highway rating is 30.5909kWh/100 miles ~= 3.27miles/kWh
    Note that the EPA ratings include charging losses.
     
    • Informative x 1
  12. ℬête Noire

    ℬête Noire Active Member

    Joined:
    Jan 30, 2018
    Messages:
    3,105
    Location:
    TX
    #92 ℬête Noire, Dec 7, 2018
    Last edited: Dec 7, 2018
    Bolt in practice is approx. 4mi/kWh at 60mph (w/no HVAC or uphill elevation change, ambient temp between 65F and 85F, no headwind) w/o the AC->DC conversion losses, which don't apply with DCFast.

    On a good day you'll get the 90mi in 30 minutes on the 50kW chargers, more like 100mi and change on something with a higher rate ceiling.

    EDIT: You do still get a bit of charging loss with the DCFast, because part of the time HVAC runs for battery temp moderation to protect the battery. How much depends on ambient and battery temp when you start. But it's really modest losses.
     
  13. jboy210

    jboy210 Supporting Member

    Joined:
    Dec 2, 2016
    Messages:
    4,603
    Location:
    Northern California
    FYI this picture is NOT the San Francisco Premium Outlets in Livermore, CA. l.
     
    • Funny x 1
  14. yuhong

    yuhong Member

    Joined:
    Mar 11, 2018
    Messages:
    276
    Location:
    Burnaby, BC
    The charging curve is well known here BTW:
    DC Fast Charging Performance - Chevy Bolt EV Forum
     
  15. brianman

    brianman Burrito Founder

    Joined:
    Nov 10, 2011
    Messages:
    17,515
    Bragging rights. Compare with 0-60 mph vs 0-200 mph.
     
    • Informative x 1
  16. yuhong

    yuhong Member

    Joined:
    Mar 11, 2018
    Messages:
    276
    Location:
    Burnaby, BC
    Personally, I expect 150kW to be mainstream for normal cars for now. 350kW might be useful for things like buses and RVs though.
     
    • Like x 1
  17. Saghost

    Saghost Well-Known Member

    Joined:
    Oct 9, 2013
    Messages:
    8,216
    Location:
    Delaware
    I'm expecting buses and RVs to follow Tesla's upcoming Megacharger standard for the Semi. We don't have a lot of details on it, but the plug they showed looks like four stacked Supercharger pin sets, so probably 5-600 kW peak or more.

    Vehicles that large can't fit into the area many Superchargers are in, anyway.
     
    • Like x 2
  18. ℬête Noire

    ℬête Noire Active Member

    Joined:
    Jan 30, 2018
    Messages:
    3,105
    Location:
    TX
    #98 ℬête Noire, Dec 9, 2018
    Last edited: Dec 9, 2018
    If Tesla uses modularized V3 SC, instead of V2, and run four of those parallel [w/liquid cooled cable] expect more like 800kW peak, which is more in line with the napkin math requirements of their 400mi in 30 min goal.

    Agree on the point about larger vehicles not mixing well with current SC locations, although I'm not sure how much Tesla is really interested in buses? City transit tends to have a lot more engineering room to work with alternate fuels, and inherently centralized infrastructure already, so Tesla is likely to just let others take over that. We've seen a good deal of reluctance for other companies to get on the Tesla SC standard in any way. Now that Tesla is moving past it's more fiscally reckless stage that removes part of the motivation for that, but I see am not convinced anyone yet is going to go there.
     
    • Informative x 1
  19. mspohr

    mspohr Well-Known Member

    Joined:
    Jul 27, 2014
    Messages:
    8,943
    Location:
    California
    • Informative x 1
  20. MorrisonHiker

    MorrisonHiker S 100D 2021.4.11

    Joined:
    Mar 8, 2015
    Messages:
    9,151
    Location:
    Colorado

Share This Page

  • About Us

    Formed in 2006, Tesla Motors Club (TMC) was the first independent online Tesla community. Today it remains the largest and most dynamic community of Tesla enthusiasts. Learn more.
  • Do you value your experience at TMC? Consider becoming a Supporting Member of Tesla Motors Club. As a thank you for your contribution, you'll get nearly no ads in the Community and Groups sections. Additional perks are available depending on the level of contribution. Please visit the Account Upgrades page for more details.


    SUPPORT TMC