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

Possible future efficiency gains

Discussion in 'Model S: Driving Dynamics' started by Jonas J. Solsvik, Nov 6, 2014.

  1. Jonas J. Solsvik

    Joined:
    Oct 10, 2014
    Messages:
    6
    Location:
    Norway
    With the the efficiency gains that the Dual motors has brought to the drivetrain, I was wondering, what else could Tesla do to improve eficiency?

    These are my guesses.

    Base range: 275 miles.

    + 5% by removing side-mirrors
    + 5% by installing regenerative suspension.
    + 5% by installing solar cells in the entire body of the car (on a sunny day)
    + 10% by reducing weight
    + 5 % more efficient wheels.
    + 5 % by covering the wheel-houses.

    275*1.05*1.05*1.05*1.10*1.05*1.05= 386 miles !

    386 miles without increasing the capacity of the battery. What do you think?
     
  2. Saghost

    Saghost Active Member

    Joined:
    Oct 9, 2013
    Messages:
    3,035
    Location:
    Delaware
    I think several of these are very optimistic. Do you have a reference standard for any of these estimates? I wouldn't have thought that going over bumps would require the car to dissipate over 15Wh per mile...

    The model S is 196 inches by 77 inches (not counting mirrors) If you assume for the moment that it's a complete rectangle, and that you can put solar panels on the whole thing, that gets you 15,092 square inches of surface. The solar panels they put on my house a couple years ago are rated for 235 W for each 39 inch by 65 inch panel - 2,535 square inches.

    So with these optimistic assumptions, you'd be looking at about 1.4 kW of nameplate rating. Take off ~30% because it isn't facing into the sun at all, then multiply by effective bright sun hours (about 4.5 here in Delaware, as much as 6 in So Cal for the yearly average full day.) So figure you might get as much as 6kWh per day from a solar Model S in brighter climates - more than your 5% if you're only driving the range once per day, less otherwise.

    Of course, those panels aren't light, nor aerodynamic - so you have to trade off the energy gained against the decreased efficiency.

    The Aero wheels that Tesla has introduced and cancelled a couple times were only rated by Tesla for an extra 3% range - not sure if something more is possible, but I'd think Tesla would have gone with the best design they could come up with.
    Walter
     
  3. ArtInCT

    ArtInCT Always Learning

    Joined:
    Sep 2, 2014
    Messages:
    1,607
    Location:
    Southern Connecticut
    I think that charging efficiency and inverter efficiency are two areas that could benefit from fine tuning.
    Getting voltage into and out of the battery pack in a more efficient manner would be of benefit for the ownership and brand.
    In addition, I wonder with the dual motor S, if the design would warrant a look at taking the large single battery pack and essentially making it two, one for each motor.
    Perhaps Tesla is actually doing this with the dual motor system in some manner?
    It would seem that each motor would have its own connection to the battery bus.
     
  4. Saghost

    Saghost Active Member

    Joined:
    Oct 9, 2013
    Messages:
    3,035
    Location:
    Delaware
    I'm pretty sure they won't. The existing 16 modules are connected in series - which means there's only one place in the wiring you can connect to get the full 400V. Also, there are a number of safety and management features at the pack level which would have to be duplicated if they went to separate packs or even separate plugs.

    Finally, they'd have to build a new pack design to handle a second set of contacts, which would mean breaking compatibility on the packs.

    The first point means that they basically have the choice between running wires from the back of the car to the front in the car or in the pack - and because of the other points running the wires in the pack incurs more cost and weight. I'll be very surprised if they have multiple battery contacts on the D cars.

    Charging efficiency and Inverter/motor efficiency are two areas I expect to see improvements in the future, but the gains won't be huge or quick - the cars are already pretty efficient, and the technologies need to advance first.
    Walter
     
  5. Jonas J. Solsvik

    Joined:
    Oct 10, 2014
    Messages:
    6
    Location:
    Norway
    Yes. I relize that i might be a tad optimistic about the suspension. I couldn't find any reliable source for this when googling. Audi and Mercedes have stated that they are implementing regenerative suspension in some of their cars, as an option. They have yet to show real-world numbers in any of the news arcticles, but they are stating that "it is increasing fuel-economy".

    I appreciate that you did the numbers on solar power for the Model S. I am confident that integrated Solar Panels will become an option to consider in the future, as PV-solar technology improves. Cheaper, lighter, more efficient and more flexible panels - makes them blend in with the design of the car. 1kW power output would increase range 5-10%. I think that makes it worth it. Remember, it decreases the need for AC aswell, as less heat is trapped in the car body.
     

Share This Page