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Track day this weekend...charge mode and driving mode question?

Discussion in 'Roadster' started by 7racer, Oct 17, 2013.

  1. 7racer

    7racer Member

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    #1 7racer, Oct 17, 2013
    Last edited: Oct 20, 2013
    Track day *update* charging, drive mode, suspension,video

    Unfortunately, my GT-R is stuck in Georgia getting suspension work and won't have it back in time for this weekends track day at MSR so instead will drive the Roadster.

    I did a search but wanted to double check.
    Since the limiting factor is the PEM/motor heat it doesn't look like you can go all out for the whole time.

    Should I charge in Range mode and drive in normal to try to keep the heat down?
    Charge Performance and drive perfomance and just say F*! it and go?

    thanks for any input.
     
  2. hcsharp

    hcsharp Active Member

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    Charge and drive in perf mode. It's usually the motor that overheats first. Unless your PEM air intake is dirty or clogged with debris, the motor temp will first send it into power limited mode. The battery will produce more power in perf mode so theoretically driving in range or std mode will give you a slightly longer track time before power is limited. But that's like putting it in power limited mode right from the start. Have fun!
     
  3. 7racer

    7racer Member

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    thanks! I just hate slowing down so would feel bummed if I could only get a couple laps in before it limits power. I see what you are saying though. Since the PEM will overheat first, discharging form perf vs std should be that much of a difference...
     
  4. wiztecy

    wiztecy Active Member

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    #4 wiztecy, Oct 17, 2013
    Last edited: Oct 17, 2013
    So I thought it was the PEM temps that were the limiting factor but as Henry indicated its the motor temps. With that said there should be a faster rise in temps on the 1.5 vs. the 2.x since it uses inductive charging from the motor which heats it up while charging. Would be nice having the side air ducts force air across the heat syncs of the PEM to help dissipate the heat and the same with the motor, to put a scoop on the bottom of the belly pan to funnel the air through the cooling fins of the motor. I think there could be some improvements made there but don't know when the heat would catch up and if it's worthwhile. Wish the Roadster could hammer the track all day like the Lotus Elise... love watching races of a dialed in Elise under-steering and pushing through the turns. One day!
     
  5. Doug_G

    Doug_G Lead Moderator

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    Turn off TC. Absolutely essential.

    I think it might be very slightly better to leave Performance mode off, as you will put slightly less power into the motor at low speeds. But that probably only matters if you have a really slow corner on the track. When you get the limit you could try switching to Performance to see if it lets you run a little longer.
     
  6. 4sevens.com

    4sevens.com Member

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    7racer - are you also in the bac mono forum?
     
  7. 7racer

    7racer Member

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    yep that's me!!! The GT-R is the track car and looking to replace it or add to it with a mono! Do you have one on order?

    - - - Updated - - -

    that's what I was wondering....the car should be pretty fast in normal mode. It would just be nice to be able to run it all session without it cutting power. Maybe I will do a run in std and performance.
    Charging the car in Performance vs Range would be the same correct? It just fully charges the battery. The discharge is just dependent on if I put in in std or performace correct?

    I always drive with the nannies off. Kinda have to in the Red run/advance group!
     
  8. 4sevens.com

    4sevens.com Member

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    No way! I figure it was you! Yes I have one on order. Where are you? I'm in Atlanta and have an AMP membership. We should run our teslas and mono's there someday. By the way AMP now has 240v 50a service. 6-50 if i recall.

    -D
     
  9. djp

    djp Roadster 2.0 VIN939

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    Last year I did a track day with Doug and was motor temperature limited after three sets of laps. This year I was battery temperature limited, but the morning was slow with rain and oil on the track which would explain the difference.

    It's extremely helpful to have 240V power at the track to do a cool down between sets. The motor cools off fairly quickly using the blower but the battery needs to be plugged into 240V for about 20min to drop 10C. You can stop and restart the charge to force the HVAC to run continuously for a faster cool down. Don't bother with 120V, it doesn't run the HVAC or add any meaningful range.
     
  10. 7racer

    7racer Member

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    hahaha that's sweet! Mono's and Roadsters! small world. I'm in Dallas Texas. Would love to run AMP! I haven't placed an order yet for the mono as you saw from the forum as I keep debating it. Do you have a ETA on yours? Does AMP have any issues running the Mono on a member day with other cars? MSR might qualify it as "open wheel" and restrict it to run in that group...which would be super boring

    - - - Updated - - -

    eh great....I called MSR today to see and they only have 110s....can I put an ice pack on the PEM or is that inviting electrocution:wink:
     
  11. djp

    djp Roadster 2.0 VIN939

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    Charging in Range aggressively cools the battery as it approaches a full charge. Performance Charge lets the battery run hot. I'd charge in Range to give yourself a bigger temperature buffer. You won't notice the difference in performance between the two unless you're doing timed runs.
     
  12. djp

    djp Roadster 2.0 VIN939

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    Ha, you can try it but it won't do a thing for your battery temperature. Once you hit 40C you'll be done for the day without 240V.
     
  13. 4sevens.com

    4sevens.com Member

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    I actually don't have a roadster. Just an MSP. Yes I've already put a deposit down for the mono. supposedly end of this year beginning of next. AMP doesn't have open wheel groups - you run with everyone else.

    I just finished an exocet and am running it at amp
    http://chows.smugmug.com/photos/i-Qbr47tm/0/M/i-Qbr47tm-M.jpg

    So your gtr is in atlanta? topspeed?

    :)
     
  14. 7racer

    7racer Member

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    holy hell...what is that! You are a worse track rat than me!

    and yep...GT-R at topspeed! Getting the suspension done to keep ahead of those GT3!
     
  15. richkae

    richkae VIN587

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    I've taken my Roadster to the track several times. Every time I have been limited by motor temperature, never by the PEM or battery.
    I always drive in performance mode, I have never experimented with driving in standard mode to reduce motor temperature.

    I almost always charge in performance mode, but if the battery temperature gets high I charge in standard to bring it back down.

    When I've been to the track the temperature is almost always in the 60s or the 70s at most - so that is probably a factor.
     
  16. 7racer

    7racer Member

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    hmm thanks for your post. How long was the track and how long were the sessions?

    Did you have the ability to charge with a 220 at the track?

    after hearing all of this feedback I might try charging range driving std.
     
  17. wiztecy

    wiztecy Active Member

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    #17 wiztecy, Oct 17, 2013
    Last edited: Oct 17, 2013
    Good to know and have all the hard user's chime in that its actually the motor that is the limiting factor for temps and appears somewhat of the battery. but I thought you'd want your battery to run hot to get more current through? I guess if its really hot it can be bad, curious djp if you remember what temps your battery was at or even what color bar it went into before the power limit? Also how far are the PEM temps following the motor before the limit? It appears these are all 2.x cars right?

    Great insight as always, thanks :)
     
  18. richkae

    richkae VIN587

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    #18 richkae, Oct 17, 2013
    Last edited: Oct 17, 2013
    My most recent track days have been on a track about 2.5 miles long and only 11 turns. I coast down the main straightaway at 90mph while everyone passes me at 130+mph ( then I chase them through the turns ). I do this to avoid heating the motor just to go in a straight line.
    I would prefer a track with more turns, but you use what you got.
    I come off the track after a few laps and let the motor cool down in the middle of the session.
    In between sessions I charge at 40amp 240v - if I didn't it would be a short day because I would run out of juice fast.

    I think you should not charge in range unless it is a super hot day and you have trouble with the battery getting too hot. There are a bunch of other posts you should find about it being bad to ask for a lot of power from the battery when it is cold.
    You want the battery to be warm - not too hot, not too cold - but just right. Like porridge.

    Charge in range or standard as soon as possible when you are done driving on the track to cool the battery back down.
     
  19. djp

    djp Roadster 2.0 VIN939

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    The battery heats up fairly quickly on its own and the HVAC will kick in when the temperature reaches 40C. I noticed the Performance indicator dropping out of white into red around the same time.

    After a Range charge my battery is usually in the low 20s, which is cool but not cold. By the time I drove to the track it was high 20s, and quickly rose to 40C after a few sets. The motor peaked at 125C, I forget the max temp of the PEM.

    Both the PEM and motor dropped quickly when resting off track. I found I could get the battery down from 40C to 30C with two rounds of the HVAC when plugged in to 240V, which was enough for another set of laps. I could keep going for the full afternoon by alternating between lapping and cool-down cycles. Weather was low 20s.

    The battery heats up faster and current draw is higher at low SOC, so you'll want to keep your battery charged as high as possible when lapping. Another reason to have high amp 240V power available.
     
  20. 7racer

    7racer Member

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    richkae,djp,

    you guys are awesome. If I could pick your brain one more time that would be great.

    I found a RV park that is 8 miles away from the track where I will be charging the Roadster overnight. The temps in Dallas are about low 45 high 65 predicted.
    At night since the car is outside, would you charge it at performance to keep the battery warm?

    and assume I have only access to a 110...would you just charge standard?
     

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