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First road trip with the car - weird range behavior - 85D

Discussion in 'Model S: Battery & Charging' started by llavalle, Apr 5, 2015.

  1. llavalle

    llavalle Member

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    Somewhere around Montreal in Quebec, Canada
    #1 llavalle, Apr 5, 2015
    Last edited: Apr 5, 2015
    Hey guys,

    I did my first road trip this weekend with my Model S 85D and noticed something weird with the range. Car is on the OEM Winter Tires (Sottozero). Interior was set to 68F with range mode ON. Car has 1200miles on the odo. Speed was VERY stable. 55mph in 55mph zone(around 50% of the distance) and 65mph in 62mph zone (100km/h zone.. I'm in Canada). Car was pretty loaded up - I estimate around 600lbs including me and my SO.

    Here are the facts :
    Leg #1 : Home -> (103.7 miles) -> Cottage House in the upper Laurentians (Quebec, Canada)
    (2 nights there)
    Leg #2 : Cottage House -> (103.7 miles) -> Home.

    Leg #1 (outside temp 50F +682ft elevation change) :
    • Started with a ranged charge (100%) that gave me 272miles of rated range (2 bonus miles!)
    • Stopped for 15min on the way
    • Got there with 53% of battery left (consumed 47%)
    • Distance on the trip meter was 105.8 miles (around 2% over the real distance)
    • Energy on trip meter was 35.5kWh with avg energy of 334Wh/mi
    • EVTripPlanner (S85 Model) : 35.4kWh w/avg of 343Wh/mi
    • EVTripPlanner (S85D Model) : 34.1kWh w/avg of 331Wh/mi

    Plugged on 120V for the night (it went down to around 15F during the night). The next morning we went in town to test the 30A J1772 charger (check for 208 or 240V, it was 240V) and did groceries, etc. Went back to the cottage home and plugged the 120V again for the 2nd night. Fun fact : something caused a big enough voltage drop for the following message to appear : "Charge Speed Reduced - Ext. Cord Used of Bad Wiring". Was plugged directly in the 120V jack - no extension cord used and wiring is brand new copper 12 AWG from brand new breaker.. and brand new panel (you get the idea..). Probably my water pump.

    Leg #2 (outside temp 25F -629ft elevation change) :
    • Started with 85% battery. Pack was cold : power limited to around 180-200 KW. Regen was as limited as I ever saw (barely 1kW). Fun fact : the regen limit went away after ~50miles of highway driving.
    • No stops along the way, straight though
    • Got home with 38% battery left (also 47% consumed)
    • Distance on the tip meter was 106 miles (also around 2% over real distance)
    • Energy on trip meter was 35.2kWh with avg energy of 331Wh/mi
    • EVTripPlanner (S85 Model) : 37.5kWh w/avg of 361Wh/mi
    • EVTripPlanner (S85D Model ) : 36.2kWh w/avg of 349Wh/mi


    Remarks :
    1. My speedo is overstating the speed by around 2%. Might be related to the Sottozero, TBC when I put the Michelin's on in 2 weeks). It seems to match what I've read here in a thread about this.
    2. ^^ This, in turn, screws with the Wh/mi number in the dash...
    3. I consumed 47% of the battery for each way. My guess is that the colder temp was offset by the net elevation change
      • 47% for 35.5kWh translates into a 75.5kWh battery pack
      • 47% for 35.2kWg translates into a 74.8kWh battery pack

    So, my questions :
    1. Has anyone measure the impact on range of running on the pirelli sottozero ? How much improvement should I expect when switching to the summer tire(19in).
    2. I can't wrap my head around the 47% energy usage VS 35.5kWh usage. That does not make sense at all. Can any one shed light on this?
    3. The "Rated" line in the graph, what's the exact value of Wh/mi or Wh/km for a 85D?
      • Wrong value would be (I'm pretty sure we can't use the whole 85kWh): 270 miles of rated range VS 85kWh = 314.8 Wh/mi
      • I've read somewhere that we have 81.1kWh usable. That translates into 300Wh/mi.

    Couple of pics for your viewing pleasure (and because you've read all of this) : Dropbox - RoadTrip

    Thanks!
     
  2. jerry33

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

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    1. I don't have experience with the Sottozeros, but the P-zeros increased my Wh/mi by over 50.
    2. Batteries have lower capacity when cold. Also SOC measurement is always an estimate.
    3. The Rated Range algorithm has changed many times. Ideal Range is more consistent (if less useful for driving).
     
  3. Cottonwood

    Cottonwood Roadster#433, Model S#S37

    Joined:
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    Colorado
    Things look pretty good, and normal.

    1. My recommendation is not use any of the Tesla OEM Winter Tires. They really are not very good winter tires. I have used the Nokian Hakka R2s, they are great winter tires, and get good range.
    2. The actual usable energy in an 85 kWh battery is about 75 kWh after leaving off the top/bottom end for battery life, "below 0" reserve, and anti-brick reserve. 35.5/75 = 47.3%; that seems very close to predictions to me.
    3. 75 kWh/270 rated miles = 278 Wh/rated mi; for my P85D, it's 75 kWh/254 rated mi for 295 Wh/rated mi. Both numbers go up a little bit if you add in a few kWh for the "below 0" reserve, but I try not to go there.
    Congratulations on a good first trip! I would recommend putting in a 14-50 or 12-30, or at least a 5-20 outlet in your cottage and buy that adapter from Tesla. Actually, you probably should buy all those adapters anyway.
     
  4. llavalle

    llavalle Member

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    Thanks guys for the input.

    1. Wasn't planning to keep the tires. We are required, by law, to have winter tires on cars between Dec 15th and March 15th here in Québec. Since my delivery was scheduled for end of February, I found it simpler to just order the winter tire package. With the current exchange rate, I paid the equivalent of $2100 USD for the set, including tires and TPMS. Seemed like a non-brainer at the time. I already had my eyes on the Nokian R2s. I guess that's one more vote for the R2.

    2. Ok, makes perfect sense (75kWh usable). Did another drive tonight : started at 90% SOC and watched the kWh gauge VS % SOC in the dash. Pretty much aligned perfectly with 7.5kWh/10% (hard to be 100% accurate since the SOC percentage does not have digits and we don't know if it uses averages)

    3.Ok, so Ideal Range is more consistent to compare trips? Good to know, I'll use that. Will be alot more precise than using SOC%.

    As for adding a 14-50 to the cottage, I had everything with me (in the car) for this. I plan to install a Nema 14-50 3R Enclosure + J1772 30A charger connected to it (friend has a Volt). I bought the enclosure + charger from a nice local company, they are made here and works wonderfully in the cold - unlike the competition! Breaker, wiring and everything needed is bought - next time my electrician friend comes around, he'll be able to install it for me (required by law too :p ).

    If some of you are in the upper Laurentians at some point, the charger will be on PlugShare :D
     
  5. llavalle

    llavalle Member

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    I think I can answer my own question. All in KM :D (Sorry for the imperial guys)

    Rated is 435km on my car (85D).

    Tonight, when I came home I had :
    1. 59% SOC
    2. 258km rated left
    3. 325km ideal left (+25.968% more efficient)
    4. 10, 25 and 50km averages were :
      1. 191 Wh/km for 245km projected (+5.3061% over rated)
      2. 186 Wh/km for 251km projected (+2.7888% over rated)
      3. 202 Wh/km for 231km projected (+11.6883% over rated)

    By using simple mathematics, these 3 now become
    1. 191 / 1.053061 = 181.376
    2. 186 / 1.027888 = 180.9535
    3. 202 / 1.116883 = 180.8605

    So my guesstimate would be 181Wh/km or 291.291 Wh/mi
    Ideal would be around 143Wh/km or 230Wh/mi

    That would mean 78.735 kWh total usable in the battery (when you hit 0km left). AKA 7.8735 kWh per 10% SOC.

    Next step, count the pixels in the screen for the rated line :p
     
  6. scottm

    scottm Active Member

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    Overthinking it maybe?

    When you drove a gas car did you trust the pump volume, or use your own flask?

    Your style of driving the EV has a lot to do with consumption. Cold battery having to do a heating cycle sucks a lot too.

    But when you realize how cheap (even free?) electrons are and how easy they are to come by you will start caring less and driving more.
     
  7. llavalle

    llavalle Member

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    I'm a statistic geek. I really love numbers. That's all :D
     
  8. Mario Kadastik

    Mario Kadastik Active Member

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    I've found that the car no longer accounts climate use in the Wh shown. The reason why I think this is that on one drive last summer I spent an hour with doors open and climate blasting waiting. That should have been a good 3-5 kWh and the estimated range left did drop, but there was no change in kWh spent nor any spike in consumption graph. So that also explains a difference to the 81kWh number as a couple of kWh will go to climate easily over a 1-2h drive.
     
  9. llavalle

    llavalle Member

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    I don't think that's 100% accurate. The car does take this into account - if you're driving. But when parked - it doesn't. I tested that last week : I drove to a supercharger to film the charging curves and on my way, I realized I would get there with 25% SOC. So I put the heater to "HI", all heated seats on along with rear defrost and heated steering wheel. Withing seconds, my average jumped.

    btw, I put my summer tires on yesterday. My commute average Wh/mi dropped from 307 to 283. Same exterior temp, around 53F, same road & speed.
     

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