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

limited regen after car charged/plugged in?

Discussion in 'Model S: Battery & Charging' started by tomp, Feb 5, 2015.

  1. tomp

    tomp Member

    Joined:
    Dec 3, 2013
    Messages:
    386
    Location:
    Durham, NC
    The other day I charged at work (J1772). My car finished charging a few hours before I left to go home. When I unplugged and started driving, I was surprised that I still got the dashed yellow 'limited regen' indicators. Shouldn't the car 'keep the battery warm' when it is plugged in? Or am I confused about something?

    Thanks!
     
  2. deonb

    deonb Active Member

    Joined:
    Mar 4, 2013
    Messages:
    3,020
    Location:
    Redmond, WA
    Did you charge to 100%?

    If so, you're regen limited due to the high charge, not the low temperature.
     
  3. Vger

    Vger Active Member

    Joined:
    Apr 10, 2009
    Messages:
    1,687
    Location:
    Salt Spring Island, BC, Canada
    You have to pre-condition the car (from the app), and make sure you are NOT in Range Mode to get pack heating before departure. Just being plugged in does not do it. Charging will generate some heat, but if charging ends (as you say) a few hours before departure, that residual heat will dissipate.
     
  4. tomp

    tomp Member

    Joined:
    Dec 3, 2013
    Messages:
    386
    Location:
    Durham, NC
    Thanks - I was not charged to 100%.
    - - - Updated - - -

    I might have been in range mode, I'll need to check that - thanks.

    However, I'm surprised that the car/battery doesn't 'maintain pack warmth' when plugged in. Wouldn't this seem like preferred behavior?

     
  5. jerry33

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

    Joined:
    Mar 8, 2012
    Messages:
    12,764
    Location:
    Texas
    No. That would vastly increase vampire energy use. The best way is to use the timer to allow the charging to complete shortly before driving and then preheat the car. Range mode should be off while charging.
     
  6. arijaycomet

    arijaycomet Member

    Joined:
    Dec 18, 2014
    Messages:
    370
    Location:
    Cleveland, Ohio
    And this is precisely why Tesla needs to add "end time" charging, the same way Nissan does. We would always end charge our Nissan Leaf so as to sit at high SOC for low periods of time, and also make sure the pack was warm when we left the house for work etc. I'm surprised Tesla hasn't added this capability.

    Also, another point to mention is that drawing power from the wall just to keep the batteries warm would also cost money that many users might not want. Still I just precondition the car to handle this, and love the new auto smart preconditioning feature for this matter.
     
  7. jerry33

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

    Joined:
    Mar 8, 2012
    Messages:
    12,764
    Location:
    Texas
    Right. Using the App to preheat the car doesn't seem to cost much, as my total electric bill was $113 last month. I pre-warmed every day, usually for two cycles, and drove ~1500 miles (two Supercharges). However, to keep the preheating on all the time it was plugged in would have used a lot more energy.
     
  8. skilly

    skilly Member

    Joined:
    Dec 8, 2014
    Messages:
    438
    Location:
    Livermore CA
    when you drive on a charge that is full enough, regen becomes limited in its ability to give back life to the battery. This will be depicted on the speedo with a dotted yellow line across the maximum range of regen allowed. As you drive father this will scale down the regen power indicator and finally disappear and max regen will commence again. Its most apparent of course when you charge to 100% - it almost completely eliminates regen...driving for a few miles and you will see it return to normal.
     
  9. tomp

    tomp Member

    Joined:
    Dec 3, 2013
    Messages:
    386
    Location:
    Durham, NC
    Agreed - in this case, however, the limited regen is due to cold, not a high SOC.

    - - - Updated - - -

    I'm confused on two points:

    1) Vampire energy use when the car is plugged in?? I don't see why vampire energy use is a concern if the car is plugged in; even if the SOC should drop a bit below the target (e.g. 88-89% when set to charge to 90%), doesn't the car re-initiate charging to get back to target?

    2) "use the timer"... what timer?
    Thanks!
     
  10. jerry33

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

    Joined:
    Mar 8, 2012
    Messages:
    12,764
    Location:
    Texas
    1. Vampire energy is the energy the car uses when not driving.

    2. You can set the charge to start at a specific time. Unless you have a very erratic schedule, it's easy to figure out how much actual charging time is needed and set the charging start time accordingly. On those days where you need additional charging (e.g. just before or after a trip) just use the App to start charging for until you reach the normal low point of the day.
     
  11. wycolo

    wycolo Active Member

    Joined:
    May 16, 2012
    Messages:
    2,428
    Location:
    WY
    TM makes every effort, or so it seems, to conserve kwh at every opportunity. So will always interpret your requests in this light as it tries to reach the chosen charge limit as quickly as possible.
    --
     

Share This Page