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Road Salt effects on the Model S

Discussion in 'Model S: Interior & Exterior' started by mknox, Aug 7, 2012.

  1. mknox

    mknox Well-Known Member

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    Hi all,

    I am a Canadian reservation holder, and quite enjoyed the Toronto test drive last Saturday.

    One of my concerns, and something I have not seen discussed anywhere, is the impact of road salt on the aluminum components and, specifically on the motor and battery pack.

    I plan to use the car as a daily driver, and my 40 mile (each way) commute takes me over roads and freeways that are saturated with road salt in the winter months. In fact, if snow/ice is expected, they often spray liquid salt brine on otherwise dry roads in anticipation of trouble. Salt spray makes my black Cadillac look like a grey car in the winter months, and I think sometimes I use more washer fluid than gasoline getting to work!

    I'm wondering if anyone has heard of this discussed, or has any thoughts about salt spray getting into the motor, electronics, battery pack and electrical connections. I believe the Roadster motor is similarly placed, so there should be experience there, but the Model S also has the battery, along with all its electrical connections, on the bottom. I believe the S's battery was designed for easy swapping, which says to me there are fittings and connections that could be trouble-prone in these conditions.

    A secondary concern is how a largely aluminum car would hold up to salt, although there are other aluminum cars on the roads these days.

    Mike
    Toronto
     
  2. SCW-Greg

    SCW-Greg Active Member

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    These days virtually all car bodies are completely immersed and electrostically(?) applied/bonded with a coating, before the first coats of paint go on. This coating is designed to protect against corrosion, and form a primer for the ensuing paint applications.

    Virtually no spot of bare aluminum is left exposed, and I wouldn't think twice about the body and frame having issues. Further, aluminum doesn't break down like steel does in the corrosion process. But I gotta say that salt on the roads is harsh! Might be issues for other smaller components though. Watch this for more info: Inside Tesla - 06.12.12 | Blog | Tesla Motors

    Here we have small gravel instead of salt, which pummels the front end of the cars as it gets kicked out at highway speeds from the car in front of you.
     
  3. Cobos

    Cobos S60 owner since 2013

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    The Audi A8 and most Jaguars have been all Al or mostly Al bodies for a long time. Here in Norway we also use lots and lots of salt on the roads during winter time. What I've heard about those extensive Al bodies is that they handle corrosion much better than steel cars. Al generally doesn't rust as it forms a few nm thick layer of Al2O3 that bonds very strongly to the underlying metal in a few seconds after exposure. You can also through running electricity through the metal create a slightly thicker layer of alumina, called eloxation that protects better.
    Having said that most of the underside of the battery is a single piece of aluminum.,and the engine enclosure should be well sealed to the elements.
    Hence I'm guessing the Model S should be one of the best cars in highly corrosive enviroments like Norway and Canada. Though I don't know of course.

    Cobos
     
  4. mknox

    mknox Well-Known Member

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    Thanks.

    I guess the moderator must have changed the thread title (I had originally just put "Salt" as the subject), but I am less concerned about the body and more concerned about the motor, electronics and battery pack underneath the car. I have been following the blogs and videos and figure Tesla is doing a decent job with the actual car body.

    Years ago, I had a car with a chrome plated aluminum bumper, and salt water must have worked its way under the plating and the aluminum turned to a white powder. Eventually the bumper looked like tin foil wrapped around mushy leftovers! There are a lot of aluminum cars on the road now, and I think the state of the art has significantly improved in this area.

    I do worry, though, about salt brine working its way into the electrical components. If it could work its way into my old bumper, could it not work its way into the battery, motor and/or electrical contact points and cables? I asked about this at the Toronto test drive event, and the rep simply said there's nothing to worry about. He said it is "coated", but I think he was referring to the dunk coating of the body that they show in the video. The guy was from California and probably doesn't have an appreciation for how much road salt is around here in the winter months.

    When it gets real cold (and salt becomes less effective), they start mixing in gravel in Ontario too :-(

    Mike
     
  5. jerry33

    jerry33 S85 - VIN:P05130 - 3/2/13

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    When it gets real cold (-25 or so) the friction properties of ice approach pavement.
     
  6. jerry33

    jerry33 S85 - VIN:P05130 - 3/2/13

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    I drove my aluminium body and steel frame Land-Rover Series III for almost twenty years in Canada and no rust problems with the aluminium body. (only surface rust on the frame)
     
  7. Alan

    Alan Member

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    I have a 6 year old aluminum bodied Audi A8 and our roads are also coated in salt in winter - no problems at all. Certainly less of a worry than a steel bodied car.

    The Tesla does have a few spots of rust where salt water has got to washers etc. I think this is a lotus thing though as its been the same on each of the different Lotus I have owned. I think Lotus take the "penny washer" description a bit too literally.

    No problem with the motor / battery etc. Certainly the battery is waterproof. The Roadster seems great whether on ice, snow, slush etc.
     
  8. Doug_G

    Doug_G Lead Moderator

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    Not in my experience. What tends to happen at those temperatures, especially if there are high winds, is tiny amounts of blowing snow gradually get compacted as the cars go by, filling all the gaps in the grain of the pavement. This produces a very dark surface called "black ice", which is perfectly smooth and incredibly slippery.

    This stuff is particularly nasty because it can be hard to spot - you think you're seeing dry pavement, especially at night. I once hit really bad black ice on a highway ramp at 70 kph, and did 2-1/2 spins. I somehow came out of the spin still on the road but now driving in reverse at 70 kph. Got it stopped and no harm done but it was a real "pucker factor" moment.

    Aluminum is normally pretty corrosion resistant, but salt appears makes things a lot worse. Hopefully the protective coatings are of high quality.
     
  9. SCW-Greg

    SCW-Greg Active Member

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    #10 SCW-Greg, Aug 7, 2012
    Last edited: Aug 7, 2012
    Yikes! Scary article, as they use deicer around here (sans salt), but still.

    Here's where road spray from underneath the car could get to the motor - what would be exposed. The good news is that this is sealed and water cooled affair (and buffeted from the relatively clean air flow) from underneath... but not to say that seals could break down.

    NOTE: These are looking down on the chassis, not looking up from underneath...
    IMG_1359m.jpg

    IMG_1360m.jpg

    IMG_1362m.jpg

    IMG_1363m.jpg


    Keep in mind this an uncoated, and unconnected (hosed and wired up) chassis, designed to show-case components. You do have a 4 year, 50,000 mile warranty.
     

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  10. jerry33

    jerry33 S85 - VIN:P05130 - 3/2/13

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    If you were to measure the temperature of the black-ice it would be much warmer than -25. (honest)
     
  11. mknox

    mknox Well-Known Member

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    One of the articles refers to aluminum wheel corrosion. I can attest to that! I generally have to dismount my tires every season and have the rims ground smooth where the tire bead sits to stop slow leaks. I generally prefer to mount steel wheels and winter tires for the winter, but my current car cannot accept steel wheels due to the size of the brakes.

    Mike
     
  12. mknox

    mknox Well-Known Member

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    Thanks SCW-Greg for the great photos. I'm not sure if I feel better about salt ingress or not :)

    Mike
     
  13. DuncanWatson

    DuncanWatson Member

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    I think your temp is missing units and so Doug and you are getting confused. -25F = =-31C. It does get to -30c in Ottawa during winter nights but it isn't the most common. Black ice starts occurring at higher temperatures. I don't know when it stops occurring.
     
  14. Cobos

    Cobos S60 owner since 2013

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    I feel the engine and battery should be pretty safe from slush and ice during the winter. The real issue should be the brakes though. We've had 3-4 year old ICE cars with brake pads and caliphers rusted all the way through.
    Part of the problem seems to be cars used in the city don't brake hard enough to boil away the slush, so the icy slush settles for a few weeks of fun rustmaking :(
    The fact that EVs due to regen usually use the brake bads even less means you should probably do an emergency brake once per trip or at least once per week during the wet season.

    Though Mercedes were infamous for a few of their model years completely rusting away, so it's not like Tesla wont be in good company :)

    Cobos
     
  15. jerry33

    jerry33 S85 - VIN:P05130 - 3/2/13

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    Sorry, the -25 was C not F. And air temperature != ground temperature. Doug's black ice is warm by comparison.

    Note that this is just a mechanical property of ice. The colder it gets the less slippery it is. Black ice is slippery because there is actually a film of water lubricating the ice.
     
  16. VolkerP

    VolkerP EU Model S P-37

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    You are both right and I chime in to help sort it out. Look at the phase diagram of water.
    Phasewater.gif
    The line separating solid from liquid is tilted backwards. Consequence: below freezing, add pressure and you get liquid water. This is why ice is slippery around -5°C: pressure of your feet generates a thin film of water that offers near to zero friction. The colder, the more pressure you need. Ice skating uses this effect. You can skate below -25°C.

    You might be able to walk on ice at -25°C and find it not slippery at all. This is because the pressure of your feet is not high enough to produce that thin film of water. But I never experienced this personally and I have no desire to explore it with my Model S. :smile:
     
  17. jerry33

    jerry33 S85 - VIN:P05130 - 3/2/13

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    Thanks Volker,

    Right. Skates have much higher contact pressure than tires do.

    Note that I am familiar with the northern parts of BC, Alberta, Saskatchewan, and Manitoba where ambient temperatures of -35 or lower are not uncommon.
     
  18. CanuckS#69

    CanuckS#69 Member

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    For examples of aging aluminum bodied cars, look at the Acura NSX and early 90's Land Rovers that are still on the road. Compare that to any similar era steel bodied car and I don't think there's much to worry about with the Model S.
     
  19. RNG

    RNG Member

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    In Colorado they use Mag Chloride which I believe is corrosive. Whenever there is MagC on the roads, I will usually wash the car with an undercarriage rinse. The MagC also permanently stains any chrome plastic parts. Wipe them off immediately. They will still be stained, just not as badly. Does anyone know of a way to remove the MagC stains from the chrome plastic parts? RNG
     

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