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Is it technically possible to replace the current standard 11 KW onboard charger?

Discussion in 'Model S: Battery & Charging' started by Benz, Nov 10, 2014.

  1. Benz

    Benz Active Member

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    The Tesla Model S is the best EV that is currently available in the market. And the Tesla Supercharger network is the best charging network that is currently being expanded globally. The combination of both is fabulous.

    That said, I would like to ask a question in this thread.

    Is it technically possible for Tesla Motors to replace the current standard 11 KW onboard charger (at some point in the future regarding new to be built Tesla Model S cars)? I would appreciate it if others would answer this question.

    I think that a single onboard charger with a higher capacity would be ideal (1 x 44 KW), but another option would be 2 onboard chargers (2 x 22 KW), and a third option would be 4 onboard chargers (4 x 11 KW).

    This would result in a higher price of the Tesla Model S, but it would be a Tesla Model S that actually is technically better too, I think. I actually think that it's worth to have a discussion about it at least.

    We have to admit that (at least in cities in Europe) there is a difference between "home charging" and "street charging". And it would indeed be nice if your Tesla Model S is well equiped to accept a higher charge rate when you are charging with "street charging".
     
  2. widodh

    widodh Model S R231 EU

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    I think the cooling loop becomes the problem. A charger probably has a efficiency of 90%. With 11kW that means you'll have 1.1kW of heat coming from the charger, two chargers means 2.2kW.

    If you go to 44kW charging, the cooling system has to cope with 4.4kW of heat. I don't know of the loop for the chargers was designed for that.
     
  3. Benz

    Benz Active Member

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    Thanks for your reply.

    The Renault Zoe seems to have a 43 KW onboard charger. Therefore, I guess that it should be possible to realise it in a Tesla Model S (but I am not sure about that).

    Imagine the situation as follows:

    There is a Tesla Model S (2 x 11 KW onboard chargers) and a Renault Zoe (1 x 43 KW onboard charger). Both are parked in the same street where there are several options availabe for AC-"street charging" (43 KW). Both the Tesla Model s and the Renault Zoe have an almost empty battery pack. And both start charging at exactly the same time.

    After 1 hour of charging, how many kWh will each car have added to it's battery pack (approximately)?
     
  4. J1mbo

    J1mbo Member

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    Wouldn't be surprised to see them go to 32A single chargers as the next step, assuming cooling is not an issue, as they seem to be shipping dual charger hardware to every market that has more than 16A AC domestic supplies. i.e. In the UK, domestic charging is generally at 30A, meaning that dual chargers are needed. Paying for the dual charger upgrade enables higher charging rates in the MS software.

    In addition, many UK motorway charging points are capable of 3p 63A 240V AC, so dual 32A chargers could give around 130 typical miles charge/hour.
     
  5. mgboyes

    mgboyes Member

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    It is technically possible for Tesla to do just about anything they like :)

    However since their vision is based around a combination of superchargers and home charging, IMO there's no chance of this ever happening.

    In the UK at least building regulations limit EV charging to 32A per phase [without the explicit consent of the power company], so 22kW is likely to be the most you can ever have at your home.

    In the UK lots of existing CHAdeMO sites have 43kW AC today, but the new units they're installing are combined CHAdeMO/CCS DC posts without an AC option, and I doubt there will be any more 43kW AC points here.

    Shame though as it would probably be much more reliable than the current flaky CHAdeMO chargers.
     
  6. fredag

    fredag Member

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    Quadruple chargers would add quite a lot of weight.

    In Norway, all public 43kW AC charging stations also offer 50kW chademo. If Tesla manages to eventually release the chademo adapter some day, it will be faster, cheaper and add less weight than adding quad chargers to the Model S.

    43kW AC could offer potentially cheaper and more stable/robust fast charging stations, though.

    Zoe uses the motor to convert AC to DC to the batteries. I suspect Tesla don't want to go that route. It would make it very fussy about the AC it gets fed, which would rule out the Norwegian IT electricity grid.

    - - - Updated - - -

    Dual chargers aren't needed to charge at 30A single phase with the European UMC.

    Model S with single chargers can charge at 32A single phase using the UMC. No problem. The blue adapter for the UMC does this. It sends the single phase voltage out on all three phase wires to the car, so that each phase wire gets 1/3 of the total current.

    Tesla's Norwegian service centres has been known to charge European spec Model S at 48A or more single phase, using modified wallbox with type2 plugs. This will only work with the Model S, not other brands of EVs.
     
  7. Cosmacelf

    Cosmacelf Active Member

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    Huh, do you have more details on the Zoe's motor converting AC to DC? Hadn't heard that before.
     
  8. David99

    David99 Active Member

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    I think the future is DC charging. AC current has advantages in a power grid, but it requires a transformer to get DC current needed by every EV. The more power you want, the larger the transformer from AC to DC and as others have mentioned, the more heat you have to deal with. This transformer is what Tesla calls a 'charger'.
    It makes so much more sense to have larger transformers at charging stations rather than having the extra size/weight and cooling in every car. Right now we need to have these in our cars as the charging infrastructure is just not there yet. But long term, DC charging (which is currently called 'quick charge' or CHADeMo, or Supercharger) will be the standard for public charging stations.
    Yes since AC power is already everywhere, it is fine to have a relatively small on-board unit. But when it comes to charging a battery at a decent speed, meaning 50 kW and up, the size/weight/cooling for an on-board unit really doesn't make sense to have in the car.
     
  9. Benz

    Benz Active Member

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    So, future EV's will not be equiped with an onboard charger?
     
  10. GaryREM

    GaryREM Member

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    +++

    Onboard AC chargers of small size are good for day to day home use. DC on the road for quick charging. I'd still want my home charger for most of the days when I'm commuting.
     
  11. dhrivnak

    dhrivnak Active Member

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    I think you are confusing two separate things. There is Level 2 charging (220V) that is common at least in the states. There is very few public chargers that are above 6 KW and the specification only goes to 20KW. Above 20 KW is DC charging and at about 45 KW it is CHAdeMO. This is a direct DC connection to the battery. The Tesla SuperCharger ups the power to 130 KW but to use DC charging you need to be SuperCharger enabled. I am told it can be added later, at a fee of course.
     
  12. AndY1

    AndY1 Member

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    Zoe has a Chameleon charger and it uses the regenerative system to charge the battery. Regenerative breaking comes from a 3 phase electric motor/generator and if you get a 3 phase electricity from the grid to the same regenrative module, you acomplish the same as if you would brake the car.

    The downside of Zoe's charger is a big efficiency loss when the car is charging from a single phase power.
     
  13. tom66

    tom66 Member

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    The Tesla Roadster did something similar.

    DC charging is very expensive to install. Much more expensive than AC charging. So I don't expect it to overtake anytime soon. Better to have the cost built into the car instead of the station to grow the network.
     
  14. Yggdrasill

    Yggdrasill Active Member

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    In Europe, you can get three phase 400V 64A, which is the same as 3x64Ax230V = 44 kW

    This can be interfaced with the car via a standard high-power Type 2 EVSE. But currently, only the Renault Zoe can take advantage of the full 44 kW. You can connect the cable to an EU Model S, as Tesla opted to equip all EU Model S with the Type 2 connector, but the Model S will only take advantage of 22 kW. Here in Norway, at least, new publicly funded rapid chargers are required to support three standards - CHAdeMO, CCS and Type 2. Of these, the Model S can only use 22 kW Type 2, as long as the CHAdeMO adapter remains vaporware.

    I think Tesla should include support for 44 kW with the introduction of the Model X in Europe (and then, going forward, all new Model S). This would eliminate the need for the CHAdeMO adapter, and would greatly increase the utility of the hundreds of public rapid chargers that will spring up in the next few years, in Norway alone.
     
  15. Benz

    Benz Active Member

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    In Europe we do have AC above 20kW:
    43kW AC !!!

    Here in The Netherlands there is a charging network of the company called "The New Motion". They currently have 32 locations where they offer fast charging with the following outlets:
    Outlets:
    1x DC CHAdeMO - 50kW
    1x DC Combo/CCS - 50kW
    1x AC - 43kW

    Link to The New Motion: http://www.thenewmotion.com/producten/snelladen/

    You can choose to read in English (see the top right of the screen).

    Cheers
     
  16. mgboyes

    mgboyes Member

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    OK a few important points to make.

    1. This thread is relevant only for European (and possibly Chinese and Australian) cars. There's no standard for AC charging above 20kW in the US. No connector rated for it. No charge points that can supply it. However the Type 2 connector used in the EU is rated up to 230V x 63A x 3 phases = 43kW, and there are public charge points in the UK (and in Holland, apparently) that can supply 43kW AC.

    2. 43kW AC is never going to be available at home. EU electrical regulations (that I sadly can't find a reference to just now) limit domestic EV charging to 32A per phase, irrespective of whether you have a monster supply to your house. You simply aren't allowed to go higher than this in your home.

    3. So we are talking solely about enabling Teslas to access rapid charging at public charging points with 43kW AC. Today those sites all have CHAdeMO, and increasingly have CCS too. Ecotricity (the operator of the largest rapid charging network in the UK) are now only installing combined CHAdeMO/CCS posts - they aren't installing any more 43kW AC. No other car manufacturer is putting 43kW AC charging in their cars - the Zoe is the only one I know of. So it seems pretty clear that 43kW has peaked, at least in the UK. Hence I'd much rather spend £450 on a CHAdeMO adaptor, or a similar amount on a CCS adaptor (yes, I know these are both non-existent today, and there are reliability concerns with CHAdeMO points) for my Model S, than an extra £2500 for two more internal chargers that will almost certainly be redundant very quickly.
     
  17. Yggdrasill

    Yggdrasill Active Member

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    I certainly agree that they shouldn't include an additional two chargers. They should upgrade the chargers so that each can handle 22 kW. This is certainly not impossible, but it might require modification to the cooling system.

    Furthermore, I think we should look a few years into the future and see how we would want things to be. Do we really want a system were people need all sorts of adaptors? I would say no. And when looking at the EU standards, there are two - CCS and Type 2. CHAdeMO might stick around, but in all probability CCS/Type 2 will become the dominant standard.

    If we accept that faster (~50 kW) charging at standard rapid chargers is an issue worth solving, there are really only two possibilities:

    1. Native support of CCS. This should be quite possible to do - you'd have the Tesla Type 2 at the top and the two extra DC pins at the bottom. Tesla Superchargers could still use the Tesla Type 2, which you'd also use for 22 kW AC, but at public rapid chargers, you'd use 50 kW CCS. Long-term, when non-CCS compatible Teslas become rarer, the Tesla superchargers could also be upgraded with the DC pins to allow for 200+ kW charging. The downside of this is that the current Model S doesn't have room for the CCS plug in the space allotted. You'd need to substantially redesign the charge port. This could be implemented on the Model X from day one.
    2. Compatibility with 44 kW Type 2. And if anyone is installing rapid chargers without 44 kW Type 2, trying to convince them that this is important. The Type 2 support on the three-standard rapid chargers isn't very expensive. You don't need any power electronics, just a communication module (same as the CCS?) and some extra wiring.
     
  18. mgboyes

    mgboyes Member

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    A few years into the future I want there to be medium speed Type 2 chargers at any location where I want to sleep (e.g. at my home, and in hotel car parks) and superchargers. And I fully expect to get what I want :)

    Everything else I consider to be a temporary stopgap, and a working CHAdeMO adaptor will be a much more useful stopgap than faster AC charging (in the UK at least).
     
  19. J1mbo

    J1mbo Member

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    My point was that they could easily replace 2 x 16A chargers with 1 x 32A charger, and that this would be a logical step if they are having to ship lots of cars with dual charger hardware anyway.

    As they use the same hardware in superchargers, 32A chargers could also reduce the BOM cost of a supercharger, or offer an easy upgrade path to increase SC output when 2 cars are charging at the same time.
     
  20. Yggdrasill

    Yggdrasill Active Member

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    Yeah, okay, you also have option 3, getting the Tesla Type 2 adopted as the DC charging standard for Europe. But I just don't think the Germans are going to accept that.

    No matter how many superchargers you have, you will always have situations where charging at public rapid chargers is more convenient.
     

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