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 or making a Paypal contribution here: paypal.me/SupportTMC

What do you make of the thinner Supercharging Cable

Discussion in 'Model S: Battery & Charging' started by mdevp, Jun 10, 2015.

  1. mdevp

    mdevp Member

    Joined:
    Sep 30, 2014
    Messages:
    454
    Location:
    nj
    Elon mentioned the new thinner liquid cooled supercharging cable and added that it "has the potential for increased power of the Supercharger long-term". Does that mean an even shorter supercharging times in the future? That would be incredible.
     
  2. No2DinosaurFuel

    Joined:
    Apr 16, 2015
    Messages:
    774
    Location:
    San Diego, California
    I like what they are doing. Imagine what power they can put through if they keep the same size cable with liquid cooling?

    I remember when Elon was saying charging power greater than 120KW is not in the foreseeable future for tesla. Guess this is another point he is changing his stance on.

    I hope there will be a day where you can plug in for 5 - 10 minutes and get from 10% to 80% SOC for another 200+ miles range. Right now with 120KW-135KW charging rate, you are looking at around 340 miles per hour. At 200+ miles in 5 - 10 minutes, you are looking at 1000 miles per hour, a 3x increase in charging speed or probably 500KW charging. That would be when gasoline will be obsolete because now EV are exactly like gas car. You juice up in 5 - 10 minutes and you are on your way.

    I am excited to see what they can do about increase the charging speed.
     
  3. rickgt

    rickgt Enthusiast owner/member

    Joined:
    Dec 13, 2014
    Messages:
    316
    Location:
    Carmel
    Used the new charger on trip to/from Silicon Valley today. Like the new cables and thinner pedestal. Got pretty normal charging rates, so the bump in performance not happening yet. Really great to solve range problems between SF and Monterey area.
     
  4. Moonwick

    Moonwick Member

    Joined:
    Dec 4, 2014
    Messages:
    52
    Location:
    Atlanta, GA
    One thing about this does worry me, though; liquid cooling a Supercharger cable is going to add to the already pretty steep inefficiencies involved in supercharging (all of that battery heat doesn't create and then subsequently remove itself ;)).
     
  5. Uncle Paul

    Uncle Paul Member

    Joined:
    Nov 1, 2013
    Messages:
    353
    Location:
    San Diego
    Standard copper wires can develop hot spots at connectors and along the wiring. By being able to circulate this wiring through a heat exchanger, the entire circuit can remain at the same temperature. Should allow greater current flow through smaller diameters. Would also make the cable more flexible, and easier to handle.
     
  6. mdevp

    mdevp Member

    Joined:
    Sep 30, 2014
    Messages:
    454
    Location:
    nj
    Ah I didn't quite understand how it worked. Thx for the explanation.
     
  7. Cottonwood

    Cottonwood Roadster#433, Model S#S37

    Joined:
    Feb 27, 2009
    Messages:
    5,062
    Location:
    Colorado
    Liquid cooling can carry away a huge amount of heat. That heat still has to go somewhere, so there is probably a radiator built into the bottom of the pedestal, along with associated pumps and fans. It's great to up the power capabilities and reduce the size of the pedestal cable, but it brings with it extra complexity (pumps and fans) that will lower pedestal reliability; hopefully by a tolerable amount.

    As for more current and power, it will be a while before we see that. There are several other places that limit the charging current and each will have to be addressed before the max power to a car can increase.

    1. The currently shipping Supercharger Cabinets are limited to 330 Amps (120 kW for an 85) per port.
    2. The wiring from the Supercharger Cabinet to the Supercharger Pedestal is part of the construction, and must pass inspection (NEC). The wiring in all the plans that I have seen, was sized to about 330 Amps per NEC Ampacity tables.
    3. 60's, 70's, and 85's hit the taper limit within the first 5-15 minutes of charging, even starting at 0% SoC. More power will only be a marginal gain on existing batteries; it will be the 105 kWh and larger batteries in the future that will really be able to take advantage higher current limits.
    4. Only conjecture, but the existing connector and the wiring in the car probably can't take much more than 330 Amps. A car designed for a bigger battery, will probably also have better connectors (liquid cooling?) and internal wiring for higher current charging.
     
  8. Todd Burch

    Todd Burch Electron Pilot

    Joined:
    Nov 3, 2009
    Messages:
    4,733
    Location:
    Smithfield, VA
    #8 Todd Burch, Jun 10, 2015
    Last edited: Jun 10, 2015
    Let's be clear--Tesla did not promise faster charge times, or even hint at them. Elon simply said it would allow for higher charge rates in the future.

    It's very likely that current battery hardware won't support higher rates, and that Elon was talking in generality about future battery packs or technologies that come down the line.

    In other words, don't get your hopes up that higher supercharger rates are coming with current cars.
     
  9. S4WRXTTCS

    S4WRXTTCS Active Member

    Joined:
    May 3, 2015
    Messages:
    1,177
    Location:
    Snohomish, WA
    I'm waiting for the robotic snake cables that will automatically attach as soon as I pull up.

    Nothing about my car has to be upgraded/changed to support this. The charge door already automatically opens and closes.
     
  10. David99

    David99 Active Member

    Joined:
    Jan 31, 2014
    Messages:
    2,051
    Location:
    Brea, Orange County
    Supercharging isn't less efficient than the built in chargers. In fact they are the exact same chargers. The only difference is that in a Supercharger there are up to 13 working at the same time. The efficiency is the same, the total power is of course higher. That means the total amount of heat loss is higher. But again, efficiency is not an absolute amount, rather its the ratio between what gets into the battery vs what is lost. That ratio is not changed in a Supercharger. There is just a higher amount of energy that needs to be dealt with.
     
  11. Khatsalano

    Khatsalano Member

    Joined:
    Mar 21, 2015
    Messages:
    648
    Location:
    San Mateo, CA
    I think this is for:

    (1) Increased charging rates one day; and

    (2) The robotic snake self-plugin ability. It's much easier to maneuver a thinner flexible snake than a big rigid one.
     
  12. wk057

    wk057 Senior Tinkerer

    Joined:
    Feb 23, 2014
    Messages:
    4,718
    Location:
    Hickory, NC, USA
    My problem with this is that the liquid cooled cables/pedestals may suffer the same fate as some CHAdeMO stations which are not sufficiently maintained and eventually fail. For liquid cooling there has to be a fan and radiator somewhere, likely in that pedestal. So, air intake and exhaust. These are outdoor units, so there will need to be a filter. Who is going to be replacing all of these filters regularly? (Yes, I know the supercharger cabinets have liquid cooling as well, but this setup has been setup is a bit different.)

    Also, a thinner copper wire is actually less efficient at carrying current, so more heat than a thicker cable. More power input is needed to compensate for this to make the power reaching the car be normal. We could likely be talking about multiple kW worth of power being wasted as heat here.

    Add on top of the above points the overall additional complexity of having a pump, coolant, radiator, thermal monitoring, etc etc to each pedestal... and honestly this just seems like a bad idea all around. They've taken something simple (a set of wires) and turned it into a pretty complex piece of equipment in comparison.

    Kudos for making it, though. It is a nifty idea. It just seems like over engineering, IMO.
     
  13. deonb

    deonb Active Member

    Joined:
    Mar 4, 2013
    Messages:
    3,020
    Location:
    Redmond, WA
    Must... resist... the urge... to comment.
     
  14. JER

    JER Member

    Joined:
    Apr 25, 2015
    Messages:
    285
    Location:
    Bristol, UK
    Superchargers are already pushing the Model S pack to accept charge a good deal faster than typical for NCA cells (~1.5C vs. 0.7C). I would not expect to see much more improvement in peak power until there are larger packs or a more capable battery chemistry.
     
  15. arg

    arg Member

    Joined:
    Aug 22, 2012
    Messages:
    741
    Location:
    Cambridge, UK
    Yes, though we don't yet know enough about it to really say where it lies on the nifty<->over engineered scale.

    I'm hoping it's relatively simple, ideally mostly passive. It would be extremely nifty if they've managed to do it in the form of an entirely passive heat pipe, though I fear it's too long and with gravity getting in the way. Assuming they do have to pump it, at least the pedestal end might be passively cooled rather than needing maintenance-heavy fans, air filters etc.

    It has more appeal as a way of getting higher power through the original size 'hose' rather than making the hose smaller - at least that way you'd only be down to (say) 60kW if the active cooling fails.

    I think your 'multiple kW' estimate of the losses may be a slightly high - assuming an effective CSA of 10mm^2 (probably several smaller wires paralleled and wrapped round the cooling core), 2m long hose so 4m of wire to be cooled = 0.0073 ohm. At 330A that's 800W - still quite a lot. Possibly my 10mm^2 estimate is low - a typical European AC charging cable has 4 current-carrying cores of 6mm^2 each, so 12mm^2 if you paralleled them (=660W); I think the HPWC cable is similar, though of course in this case there's the cooling pipe volume to add as well.

    We need more photos of the pedestals and measurements of the cable!
     
  16. WarpedOne

    WarpedOne Supreme Premier

    Joined:
    Aug 17, 2006
    Messages:
    2,653
    Location:
    Slovenia, Europe
    Such comparisons are moot.
    "Classic" way of charging a Lithium battery is ConstantCurrent / ConstantVoltage profile. In such profile a 0.7C is upper limit on current in constant current phase that extends from 0%-80% SOC.
    Superchargers behave completle differently - they continuously vary current and voltage.
    Hence one cannot directly compare SC peak of 1.5C with 0.7C rate with CCCV charging profiles.
    But still, SC only better utilize chemistry capabilities than CCCV profile does. Higher charging power will still mandate more kWh in a battery pack with same chemistry and/or a pack with different chemistry.
     
  17. mgboyes

    mgboyes Member

    Joined:
    Apr 16, 2014
    Messages:
    811
    Location:
    United Kingdom
    Obviously we have no idea why and how Tesla set the limits they did, and how cautious they are, what headroom remains etc.

    One thing that is clear is that charging rates for Model S are quite low relative to other BEVs.

    There are various BEVs around the 22kWh capacity level which can accept 40-50kW charging, so on an equivalent basis a Model S ought to be able to take 160-200kW. The Kia Soul EV can charge at 3.3C (100kW into a 30kWh pack)!!

    Other cars also taper much less aggressively - a Renault Zoe can charge at 40kW (1.8C) from 0% all the way up to about 70% SOC whereas the Model S starts tapering at around 25%.

    I suspect the limiting factor is the cables inside the car, which most likely cannot go above 330A for longer than about 15 minutes.

    If we want faster supercharging we need less tapering, not higher peak power.
     
  18. WarpedOne

    WarpedOne Supreme Premier

    Joined:
    Aug 17, 2006
    Messages:
    2,653
    Location:
    Slovenia, Europe
    I suggest you double check your sources.
    Just because a car has chademo or CCS plug it does not mean it will charge at maximum power the standard describes.
    Heck, there are even plenty chademo chargers that cannot deliver full power that standard describes, just about 20kW and overheat when a car demands that power for a longer period.
     
  19. wws

    wws Member

    Joined:
    Aug 11, 2014
    Messages:
    195
    Location:
    California
    After the shareholders meeting, my son and I walked over to take a look. There is a heat exchanger in the base of each pedestal. If you look carefully at some of the photos in the Mt View Supercharger thread, you can see the vents along the bottom of the base. The coolant goes through the cable up to its termination, but the car side connector is exactly the same part that is used by the HPWC.

    They had a mockup of a supercharger pedestal with the usual cable for comparison. The cooled cable seems to be about 1/2 the diameter of the non-cooled cable.

    Tesla is obviously watching this installation very closely. There were several engineers with laptops hiding in the supercharger cabinet enclosure area taking real-time observations. The design engineer that I talked with had no idea when the new setup would be deployed to other new or existing sites.
     
  20. No2DinosaurFuel

    Joined:
    Apr 16, 2015
    Messages:
    774
    Location:
    San Diego, California
    I think people are forgetting tesla needs to cool the connectors too. So engineering something that can cool the connectors means more complexity. If they can get this right then all the better for everyone, but the best solution might be just to use carbon nanotube wires once the cost goes down. You should be able to put 2x the power and keep the same size wire.
     

Share This Page