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

How come the regen doesn't get to the "limit" line?

Discussion in 'Model S: Driving Dynamics' started by ljwobker, Feb 14, 2015.

  1. ljwobker

    ljwobker Geek.

    Joined:
    Nov 30, 2012
    Messages:
    210
    Location:
    Raleigh, NC
    Everyone already knows that the dashed yellow line comes on whenever the regen for the car is limited. However, in my case the dashed yellow line might be at 30 or 40 KW, but when you can see the yellow line, the green regen bar never actually gets to that threshold....

    this doesn't make any sense to me... does anyone know **why** the green regen bar never actually gets to the dotted yellow line? It seems sensible that the yellow line would be the actual limit and as the car warmed up or the battery stays charged decreased the region would line up exactly with where that line was drawn, and the line would creep from the limit back to a full sixty-ish KW of regen...

    thoughts?
     
  2. jerry33

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

    Joined:
    Mar 8, 2012
    Messages:
    12,766
    Location:
    Texas
    My guess would be to insure that the bars never cross the yellow line, even if there is some data noise. I can just see the complaints (with photos) about battery degradation because the yellow line is surpassed.
     
  3. pgiralt

    pgiralt Active Member

    Joined:
    Jun 16, 2013
    Messages:
    1,476
    Location:
    Cary, NC
    I've wondered the same thing. Also, after the yellow line disappears, it takes some time before you can actually get all the way to 60kW regen.
     
  4. rlang59

    rlang59 Member

    Joined:
    Feb 27, 2013
    Messages:
    923
    Location:
    US
    I had a brand new loaner last week and regen actually got to the limit line on it.
     
  5. Evbwcaer

    Evbwcaer Member

    Joined:
    Jun 21, 2014
    Messages:
    471
    Location:
    Minnesota
    My car started going to the limit line on occasion after 6.1. In most cases it does not go to the limit line and I often get no re-gen under coasting when the limit line is close to the baseline.

    One thought I have is (just pulling numbers out of thin air) is that the battery heater might be using 5kw and so 5kw of regen, when available, is being used to power the battery heater, rather than going back into the battery and that is why you see a difference between the lines.
     
  6. NOLA_Mike

    NOLA_Mike Active Member

    Joined:
    May 11, 2013
    Messages:
    1,564
    Location:
    Hammond, LA
    Mine regularly goes to the yellow dashed line (when the yellow line is there indicating a limit). Having said that, there is also a short period of time after the yellow line disappears from the display when the regen will still only go to where the yellow line was (a phantom limit if you will).
     
  7. denverdan74

    denverdan74 Member

    Joined:
    Dec 14, 2013
    Messages:
    10
    Location:
    Denver, CO
    Are you running with Range Mode on or off? On - I've seen this behavior. Off - Regen is typically always maxed based on speed of course.
     
  8. mknox

    mknox Well-Known Member

    Joined:
    Aug 7, 2012
    Messages:
    8,570
    Location:
    Toronto, ON
    Mine has worked that way on every flavor of firmware for almost two years now. Never quite gets to the line.
     
  9. NOLA_Mike

    NOLA_Mike Active Member

    Joined:
    May 11, 2013
    Messages:
    1,564
    Location:
    Hammond, LA
    Hmmm... Since Tesla sent the Torque Sleep Firmware I've been driving with Range Mode ON. Prior to this I had never turned Range Mode On. So, I'm not sure if I've noticed different behavior depending on whether Range Mode is ON or OFF - and my statement about hitting the dashed yellow regen limiter line was made based on seeing it hit numerous times in the last couple of weeks - with Range Mode ON.

    Mike
     
  10. reddy

    reddy Member

    Joined:
    Jan 26, 2013
    Messages:
    412
    Location:
    Amarillo, TX
    I have always assumed that the line limited the amount of power that the regen would produce, but the display showed what was actually being returned to the battery.

    Particularly when we have a lot of demand for heating , the gap is really wide since Battery Regen = (Motor Regen minus electrical load) , the difference being the heating and electronics.
     
  11. ljwobker

    ljwobker Geek.

    Joined:
    Nov 30, 2012
    Messages:
    210
    Location:
    Raleigh, NC
    I don't *think* it's related to temperature, because at the moment I'm living in the Bay Area where for weeks at a time the ambient temperature is never below 50F or above 75F... and my car at least has behaved this way since I took delivery. It seems not to matter what the cause of the limit is -- high SoC, low temperature, etc... I've *never* seen my green regen bar get to the dotted line. In mine it basically tracks to about half of what the dotted yellow says I can get.

    And there is definitely a phantom limit effect in mine as well - once the dotted line disappears it still takes a few miles/minutes before the regen gets to the full 60kWh.
     
  12. scaesare

    scaesare Active Member

    Joined:
    Mar 14, 2013
    Messages:
    3,940
    Location:
    NoVA
    #12 scaesare, Feb 16, 2015
    Last edited: Feb 16, 2015
    The limit lines have always been a little flakey. Then regent limit line always has a little margin below it as described here... and it often disappears when there's obviously still a limit in effect. Sometimes it will disappear for a bit then return. I've wondered if there's a little hysteresis built in to prevent overshoot.

    The power limiting lines also exhibit some weirdness. They aren't always present when the car is power limited... and when you floor it they'll appear momentarily within the swept area of the power meter... so they aren't quite limiting at the level they indicate. Then they'll disappear as the power needle swings back down. I believe this is because of instantaneous voltage drop during high current situations.
     

Share This Page