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

Roadster Sport RED vs WHITE Performance modes

Discussion in 'Roadster: Technical' started by scott451, Aug 25, 2010.

  1. scott451

    scott451 KWH-PWR#1349Sprt,S Sig#96

    Joined:
    Apr 2, 2009
    Messages:
    251
    Location:
    Palo Alto
    #1 scott451, Aug 25, 2010
    Last edited: Nov 13, 2010
    I've received a number of PM/emails about the performance of the roadster Sport and recent firmware changes. I did some data collecting on a friends sport and here's what I found:

    Yes. The torque in Standard mode is limited to 265 ft-lbs vs 295 ft-lbs in performance. (see plot below)

    attachment.php?attachmentid=985&d=1282720654.png

    Yes. When VDS 'Performance' turns red, the PEM temp is >= 45C and the max torque is limited to 273 ft-lbs. When 'Performance' is white, the max torque is 295 ft-lbs. The good news is that the PEM fan is very powerful and it cools the PEM down in about 30 seconds. (@26C ambient. YMMV)

    attachment.php?attachmentid=983&d=1282720649.png

    When the PEM temperature reaches 45C, the max torque will be limited to 273 ft-lbs

    attachment.php?attachmentid=982&d=1282720648.png

    In the new firmware, the last blue bar is on for PEM temps 43C to 60C.

    This screen has changed how the battery temperature is displayed. Attached is the data from my 2008 roadster. (I have also checked it against a recent roadster sport VDS )

    attachment.php?attachmentid=986&d=1282721159.png

    Disclaimer: My conclusions & data could be wrong. I don't work for Tesla nor have any friends that do. I'm just passionate about Tesla's products and understanding how they work. The data is the result of my own analysis of my roadster and discussions with (and log data from) other owners.
     

    Attached Files:

  2. raymond

    raymond Member

    Joined:
    Jan 14, 2008
    Messages:
    345
    Location:
    The Netherlands
    Scott, thanks for the info! I've actually been looking around for these figure quite a while hoping Tesla would provide these one day.
    Now about performance mode: firrst I thought it would simple dial in higher limits for e.g. motor current, but later I heard that charging in performance mode pre-heats the batteries. Does this mean that warm batteries have a higher power discharge (at the cost of shorter life span)? If so, you would need to select performance mode some times before you actually get maximum performance.
    Any thoughts on this?
     
  3. bolosky

    bolosky Member

    Joined:
    May 5, 2009
    Messages:
    422
    What instrumentation did you use to get that data?

    I'd love to see comparable graphs for the other Roadster models (2008, 2010 non-Sport, Roadster 2.5 if it's any different from 2.0; I just heard that the 2.5 PEM has hi-temp chips that allow it to run much hotter).

    It's also interesting that a hot PEM is limiting torque rather than power. My experience with getting Roadsters toasty is that when the motor is hot it limits torque but the PEM limits power. Maybe it's different for the lower temps you're dealing with; I'm thinking of when you get all the way to red and the warning comes up on the VDS.
     
  4. DrTaras

    DrTaras R254->R725->S1364-->X769

    Joined:
    Dec 2, 2007
    Messages:
    1,247
    Location:
    Woodland Hills, CA
    Scott- This is awesome! You have answered so many questions and so succinctly! I don't doubt your data crunching ability at all, but one thing I know for sure... I validate what you said: "I'm just passionate about Tesla's products and understanding how they work." Thank YOU! :)
     
  5. scott451

    scott451 KWH-PWR#1349Sprt,S Sig#96

    Joined:
    Apr 2, 2009
    Messages:
    251
    Location:
    Palo Alto
    #5 scott451, Aug 26, 2010
    Last edited: Nov 16, 2010
    I don't think that the battery is "heated" in performance mode. The only time I have seen a heat record in a logfile is during charging when the battery very cold. In performance mode, the battery is allowed to run hotter. [update 11/2010] It appears that cooling is reduced when charging in "performance" mode. So the battery will be hotter when fully charged.

    Yes (see graph below). The curve shows that for the same current, at a higher temp, the output voltage is higher so the total output power is higher. For max power, you get diminishing returns for temperatures over 45*C. And No, I haven't noticed any delay selecting performance.

    attachment.php?attachmentid=987&d=1282846484.png
     

    Attached Files:

  6. scott451

    scott451 KWH-PWR#1349Sprt,S Sig#96

    Joined:
    Apr 2, 2009
    Messages:
    251
    Location:
    Palo Alto
    #6 scott451, Aug 26, 2010
    Last edited: Aug 27, 2010
    Actually, it's the motor current that matters. I didn't plot it, because the motor current is correlated to the torque (and it's easier to get torque from the VDS). It really comes down to how much current you can pump out of the PEM without overheating it.

    I would describe it as a "warm" PEM is limiting peak power by 7.5%. A hot PEM limits the power a lot more. Tesla is taking advantage of the thermal mass (WattSecond/degC) of the PEM heatsink to dump peak power into a warm/cool heatskink, which would normally overheat a hot heatsink. It's a brilliant move on Tesla's part because it gives you a burst of power when you need it (E.g. to beat a corvette off the line.) :cool: As a comparison, it acts a like a burst of Nitrox in an ICE, more power, but you can't use it all the time.
     
  7. scott451

    scott451 KWH-PWR#1349Sprt,S Sig#96

    Joined:
    Apr 2, 2009
    Messages:
    251
    Location:
    Palo Alto
    This thread has been split... This thread (the original post) is about the effect of a hot PEM limiting performance.

    Comments/Questions about the impact of a hot battery / battery cooling have been moved to this thread The-effect-of-Performance-mode-on-battery-life
     
  8. kgb

    kgb Member

    Joined:
    Sep 22, 2009
    Messages:
    605
    Location:
    Houston, TX
    Just curious... I have a question for people living in hot locales.

    This is my first summer with my roadster. I live in Texas. The temperature during the day can frequently get above 100F and the thermometer in the vehicle frequently measures the outside temp (near the asphalt/concrete) as 115F or higher. As you can imagine, I need to use the wimpy A/C. As the weather was getting hotter and hotter, I noticed that my performance mode spent more and more time in the red. The other day, I was trying to give someone the Tesla grin, and the car was not "performing." So I put it into performance mode, and it would not switch out of "red." I turned off the A/C and waited, and still "red."

    I mentioned to my Tesla Ranger that my vehicle was spending more time in performance limited mode rather than white performance mode, he said that I was using performance mode too much and that it would wear out my battery.

    What is everyone else's experience? Do people in hot climates just have to suck it up and deal with a slower roadster in the summer?
     
  9. S-2000 Roadster

    Joined:
    Apr 10, 2009
    Messages:
    636
    I wouldn't say that it's 'slower' - every Tesla Roadster is limited to 125 mph due to the single-speed gear box.

    Basically, Performance Mode is more than a 10% increase in torque compared to Standard Mode, but at least Performance Mode in red is still 3% more torque than Standard Mode.

    Personally, I stay away from Performance Mode, and the few times I've used it I've been able to get into the red fairly quickly. Road racing is illegal, ya know.
     
  10. scott451

    scott451 KWH-PWR#1349Sprt,S Sig#96

    Joined:
    Apr 2, 2009
    Messages:
    251
    Location:
    Palo Alto
    #10 scott451, Jul 2, 2011
    Last edited: Jul 2, 2011
    If the air temp at the PEM fan intake is 115F (46C) "performance" will always be red. The A/C does not cool the PEM. If the fourth blue bar is on for the PEM in the VDS temp screen, performance will always be "red"

    Huh? When you are in "red" performance, you draw less current from the battery. So being forced into "red" by the air temp would be easier on the battery.

    Yes.
     
  11. S-2000 Roadster

    Joined:
    Apr 10, 2009
    Messages:
    636
    ... compared to Standard Mode or full 'white' Performance Mode?
     
  12. TEG

    TEG TMC Moderator

    Joined:
    Aug 20, 2006
    Messages:
    17,252
    Location:
    Silicon Valley
    But top speed can be further limited by temp. I think I heard that flat out on the Autobahn may "govern" you down to something like 105mph on a hot day.
     
  13. S-2000 Roadster

    Joined:
    Apr 10, 2009
    Messages:
    636
    I'm approaching one month with the Roadster; and 2,000 miles. I'm also learning that the RED Performance Mode comes way too fast, even in the cool Pacific Northwest weather. I've had the thing turn red after only a single, full-throttle acceleration. Thankfully, it does cool down to white fairly quickly, but Performance Mode doesn't seem to be a feature that you can rely upon being there any significant amount of time.

    In other words, I'm not surprised to hear that the speed can be limited. Hopefully, I'll never know.
     
  14. DrTaras

    DrTaras R254->R725->S1364-->X769

    Joined:
    Dec 2, 2007
    Messages:
    1,247
    Location:
    Woodland Hills, CA
    First, let me say that when you get advice from scott451, you are getting about the most accurate info from our non-Tesla sanctioned tech guru! Take his word to the bank!
    Definitions are the lynch-pin on which answers are derived so allow me to better characterize the issue as I SUFFER frequently from it as well.

    Last issue, first. I constantly use performance mode & I know that it will decrease my battery life. Using the car probably also decreases battery life (this is a metaphor so no tangent threads needed) as does hard acceleration wear down tire life (tangent thread already started elsewhere) but it is what speaks to MY soul, so keep on using "Performance" mode if it also speaks to you!

    In "Performance" mode you can have the white letters which is normal, & per scott451, "If the air temp at the PEM fan intake is 115F (46C) "performance" will always be red." but that is not limiting your performance, however it is informing you that the PEM is getting quite hot and will soon get to the next threshold (scott451 will tell you what that is) where the car will LIMIT your performance and the acceleration becomes sluggish. A beep-beep is audible and I believe you will get a "power limit" come up in red on your right side of your dash board. Honestly, this is the Achilles Heel of the car and what I heard they were working on for future Teslas. How do they keep the batteries cool in extreme temperatures, either ambient or because of extreme demands on the performance. Still love the car; have had two Roadsters (tangent thread already started elsewhere) and had the same problem in each though in the 2008 they only had one PEM fan and in the 2010/11s they had 2 fans which helps the situation a bit.

    kgb... welcome to the club! Membership still has its privileges!
     
  15. NigelM

    NigelM Recovering Member

    Joined:
    Apr 3, 2011
    Messages:
    13,257
    Location:
    Sarasota, FL
    Yes, but we get to drive with the top off for a huge part of the year! :biggrin:
     
  16. Doug_G

    Doug_G Lead Moderator

    Joined:
    Apr 2, 2010
    Messages:
    15,853
    Location:
    Ottawa, Canada
    Oddly enough, I don't get to use it in hot weather. Case in point: 31C (88F) here, sunny, and humid... wife takes one look in the garage and says she wants the soft top and A/C.
     
  17. NigelM

    NigelM Recovering Member

    Joined:
    Apr 3, 2011
    Messages:
    13,257
    Location:
    Sarasota, FL
    #17 NigelM, Jul 4, 2011
    Last edited: Jul 4, 2011
    Was 96F here this afternoon, but went with the top off anyway. So long as I keep moving the air keeps me cool enough. A baseball cap is important to avoid sunburn; long waits at stop lights are miserable tho...
     
  18. Nvbob

    Nvbob Roadster 1256

    Joined:
    May 6, 2009
    Messages:
    229
    Location:
    Just east of Lake Tahoe, Ca.
    Um, isn't 96C about 205F?

    It was about 98-102F here (Carson City, Nv) and we took a nice long drive down to Bridgeport, Ca (395 south) and back via Markleeville (Highway 89 to Highway 88 to 395). We have the Taylor Mesh Top (thank you Eric! It worked fantastically) and we were very comfortable.
     
  19. NigelM

    NigelM Recovering Member

    Joined:
    Apr 3, 2011
    Messages:
    13,257
    Location:
    Sarasota, FL
    Ooops, corrected my post. Those darned Canadian Celsius got me confused....
     
  20. Nvbob

    Nvbob Roadster 1256

    Joined:
    May 6, 2009
    Messages:
    229
    Location:
    Just east of Lake Tahoe, Ca.
    Nigel, why don't you PM Eric (vfx) about the mesh top? You will not regret it, it is very well worth it.
     

Share This Page