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Model S - Impact of smart suspension height/position on Wh/M

Discussion in 'The UK and Ireland' started by Waiting4Three, Aug 23, 2018.

  1. Waiting4Three

    Waiting4Three Member

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    Hi All,

    Newbie here and excited to take delivery of my S tomorrow (and also on the long wait for my 3). As I will be doing some regular return trips of 230 miles mostly on the Motorways, I was wondering if there has been any study on the impact of the suspension position on the drag and subsequently on the Wh/M.

    I have read contradictory details on this i.e. more ground clearance means more air flow under the car and therefore less resistance = more mileage (Wh/M) and on the contrary, less clearance means less drag and therefore more Wh/M.

    Should it be set to Very High or Low?

    Thanks,
    Waiting4Three
     
  2. DJP31

    DJP31 Member

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    Congrats on the car, a pic or it didn’t happen ;)

    I’ve no idea about the answer to you question, but I suspect it’s marginal. Knocking a few mph off has a marked effect, and when in doubt drafting behind a high vehicle can be very helpful.

    The trip graph in the car is extremely useful and you can adjust your speed according to how to changes the projected state of charge.

    This time of year is great, come the misery of winter take 20-25% off your range.

    Enjoy, it’s a game changing car.
     
  3. Terry_B58

    Terry_B58 Member

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    As #DJP31 says, the best way to reduce Wh/m is simply to reduce speed.

    Be aware that there have been some 'horror stories' regarding excess uneven tyre wear when the car has been set to the lowest setting.
     
  4. WannabeOwner

    WannabeOwner Active Member

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    Bjorn did a test / video I think ... [toddles off to find it] ...



    so basically "not enough to make a tangible difference"

    50 MPH in roadworks / traffic will do wonders for your range though :)

    Unless you have 100-battery-pack I think that will be tight. My 90-pack is 220 miles real-world range, and I charge to 100% if my journey is more than 160 miles (in case of detour / torrential rain / etc.). I work on the basis of keeping 20-miles "just in case", which is around 10%.

    If your journey is multiple-stops (e.g. travelling-salesman) then in Winter stopping for an hour will let the battery get cold and have an associated energy-penalty each time you then set off.

    If you have destination charging that will solve the problem, even a 13AMP plug for 4 hours will give you ~25 miles, which could well be the difference between "comfortable" and "squeaky-bum". (If so you might want to source a decent extension lead etc.)

    Supercharger somewhere on your route will solve the problem, or if not a CHAdeMO (usually 50% speed of Supercharger). You only need a top-up enough to get-you-home, so probably only 5-15 minutes (less in summer, more in winter)

    I suggest you try your journey in A Better Route Planner (pick the model, try with "bad weather" setting and maybe with a 90% speed setting instead of 110% :). If you do have to stop to charge, and at a Supercharger, then "just drive". Shorter journey duration, overall, driving faster and charging longer (up to something like 90 MPH, so more than I presume you will be doing :) )
     
  5. arg

    arg Supporting Member

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    At launch, cars with the air suspension auto-lowered at speed in order to gain this efficiency advantage, though I never saw any actual numbers.

    After the collision with road debris incidents (which caused battery fires), the minimum height setting was raised to give more ground clearance (and so need a bigger piece of debris for you to hit it).

    After the protective plate modification the software may have changed again but I don’t think it went back to the original level.
     
  6. Peteski

    Peteski Active Member

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    Higher will almost certainly be a little more draggy (whatever you read to the contrary was almost certainly BS). Higher ride height will also be less stable at high speed.

    Therefore set it to low on the motorway and anywhere else where you don't need more ground clearance. "High" and "Very High" settings are only for mild off-road, huge speed bumps and transitioning from a steep slope where you might scrape the ground.

    If you do run it low all the time, keep an eye on tyre wear across the treads as lowering it will increase the camber angle slightly from standard.
     
  7. Waiting4Three

    Waiting4Three Member

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    Thanks all for your responses and tips. The trips will be on M40 or M1 and have already identified couple of superchargers on the route. I was just exploring the options to reduce the stop/charging times to the minimum. I think I will have to alternate the stops (North/South) for every alternate round trips get the efficient charging time.

    @WannabeOwner - Thanks for the video, its quite helpful. I also read that Tesla auto manages the suspension level based on speed of travel, just curious whether the software overrode Bjorn´s settings ;)

    @DJP31 - I am taking delivery today eve and will post the pic soon.

    Cheers,
    Waiting4Three
     
  8. Peteski

    Peteski Active Member

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    Not if he switched off the auto lowering function - which you can. It's a very simple function that simply lowers the car at a threshold speed which you can adjust or turn off entirely.

    For example if you wanted to run low on motorways and standard everywhere else, then you would just set it to standard ride height and self-lowering above say 60 mph. Simple as that.
     
  9. WannabeOwner

    WannabeOwner Active Member

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    #9 WannabeOwner, Aug 24, 2018
    Last edited: Aug 24, 2018
    And to let elderly inlaws get out of the car ... they hate getting out of my (coil springs) MS :oops:

    I wouldn't worry too much about optimising the efficiency of your charging time, although things I factor in are:

    Don't "pair". If a car is already charging at Stall 3A then do not plug in to 3B (and vice versa) [second car to arrive gets a lower charge rate until first car tapers/leaves]. If the only stalls free are "paired" then [if you can] choose the partner who has been there longest. I park up and bag a space, and then talk to drivers [if they are in their cars] and move if it seems appropriate. But I have had-to-wait just once in 50,000 miles of driving, and had-to-pair-and-moved only on a coupe of occasions. In practice I rarely even have to pair.

    Stop on the return trip, not the outbound. On Outbound I might be delayed (all stalls full, paired, etc.) which would make my arrival time at Client unpredictable.(Of course if you don't have range for the outbound then charging is a necessity Natch!). So I chose Model, and therefore Range, so that the trips that I routinely do I would have enough range for "Get to client AND back to Supercharger, even in Winter"

    The driver needs a break :) So on days when I drive more than the 220 real-world mil range I'm OK with that. Actually mostly my returning-home charge is probably only 5 minutes, maybe 15 at the absolutely most (a day with a 300 mile round-trip). A Pee and getting Coffee takes longer than that ...

    Charging, on the way home, at the "nearest to home" Supercharger (when you have a choice), means that the Trip Consumption graph will be giving you a very accurate prediction of energy-needed [to complete trip], so you can charge the minimum to get home (and then recharge, overnight, at home).

    Also, charging at "nearest to home" location means your battery is lower SoC. Battery charges at linear speed up to 70%, and almost as fast to 80%, and then MUCH slower. So only charging your battery to 70%, or 80% if necessary, is the most time-efficient - hence stop later in your journey, when battery SoC will be lower. The percentages are true for all models [give-or-take], so a 100 puts on 33% more MILES in the time, compared to a 75 (but above 80% SoC they are both about the same)

    If you charge earlier in your trip and then hit traffic, and have very economical consumption for half-an-hours frustrating drive :mad:, you will arrive home with spare energy, and have wasted some time at the charging stop.

    Coming off a motorway junction, getting to the stall, jumping out and then the reverse to get back onto the motorway adds 5 minutes to your journey (same if you had to refuel an ICE of course), so multiple Supercharger stops have that additional penalty.

    Reducing speed (not that I ever do :rolleyes:, except if range is critical) is an option. But you are increasing journey time, so as long as you can get to Supercharger you are better to press-on. I've got home at 2% once, the weather was foul and cost me a lot of range ... not an experience I want to repeat!

    If you are tight on range pull in behind an Artic. Even on cruise follow-distance of MAX the consumption saving is worthwhile - and of course you will also be at the max highway-speed for HGV and temptation to go faster is removed :) I've done that a couple of times where my nearest , easily reached, Supercharger was a detour on another branch of the motorway which was going to add 15 minutes to my journey time and I was stretching-range in the hope of making the Supercharger on the more direct route. At the point at which I got to the junction-decision I had the preferred Supercharger in Satnav so I could see the Trip Consumption Graph as to whether I was going to make it ... so decision was easily made, and safe.

    If your life involves having to do emails then stopping at Supercharger, and doing emails, is same as getting home, sooner, and then doing emails, so can be a time-neutral thing.
     
    • Informative x 1
  10. Waiting4Three

    Waiting4Three Member

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    • Like x 1
  11. DJP31

    DJP31 Member

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    Looks lovely, hope you are very happy!

    I might be going over familiar ground but it’s important - Passive Entry. A fair few cars have been stolen by thieves using the key fob amplification method. The solution is to turn off Passive Entry in settings, or keep the keys (both sets) in an RFID blocking pouch. I turn PE off when I get home in the evening, and resent me in the morning. I also keep the keys in a pouch as a failsafe.

    On a lighter note, the car looks very clean, have you bought the obligatory cleaning essentials? Power washer, snow foam attachment, two buckets, wash mitts, micro fibre drying cloths etc etc :D
     
    • Like x 1
  12. WannabeOwner

    WannabeOwner Active Member

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    Or just employ a Jeeves :p
     
  13. Waiting4Three

    Waiting4Three Member

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    Thanks DJP31. Will remember to set the appropriate Passive Entry setting, thanks again. Regarding cleaning, I am thinking of the easy/lazy way out...get cleaned by Car Valet;)
     
  14. WannabeOwner

    WannabeOwner Active Member

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    Initially we had a man-in-a-van come every few weeks, that worked really well until unfortunately he was taken ill and we haven't found a replacement. made a nice change havign a clean, tidy, car ... as previous cars have been cleaned only when desperate!
     
  15. DJP31

    DJP31 Member

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    If you mean the pro detailer type then ok, if you mean the local hand car wash merchants then :eek:. They’ll have your lovely car covered in swirls and scratches in no time :(

    @WannabeOwner - cleaned every few weeks :eek:. Drop the “few” in that sentence and sanity returns o_O
     
  16. WannabeOwner

    WannabeOwner Active Member

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    :) Car is wrapped, couldn't see (to me at least) that it needed doing every week. Might be the whole reverse-snob-thing though ... have vanity plates on everything BUT the Tesla; had thought of getting a refresh-nose-cone but have decided I prefer Classic - now that I see a Tesla or several on every journey I make ...
     

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