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Winter Regenerative Braking Tip?

Discussion in 'New England' started by Driver Dave, Dec 5, 2016.

  1. Driver Dave

    Driver Dave Member

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    Oct 10, 2016
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    Location:
    Boston, MA
    I discovered the regenerative braking doesn't work either because:

    1. You have topped off the battery full and there is no place for those extra electrons to go.
    2. Your battery is too cold to be charged and needs to heat up first.

    I have been playing around with a solution to 2.

    1. Charge to 85% overnight
    2. Cold Morning: Set to 90% and Charge Over Breakfast
    (2b. Turn on climate while in app to heat up car while on shore power - just for warm car - does nothing for braking)
    3. Get Into Car To Warmed Up Battery? And Regen Braking Working?

    So the question is: Does charging a bit in morning (but not to full) help the regenerative braking become active right away on a very cold morning because it warms up the battery for charging?

    I just started testing this theory, but wondered what other more experienced winter Tesla owners thought?
     
  2. Doug4650

    Doug4650 Member

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    I live in Somerville, MA and do something similar. This is my second winter.

    Set my level to 90% and start up at 5:00AM. By the time I leave the car is either charged or almost charged. But you are correct, I get full regen as I drive off to work. But with the cold, when I leave work, regen is limited by the cold. Seems to work well.
     
  3. EdA

    EdA Model S P-2540

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    Yes, because it warms up the battery.

    If you overnight near a supercharger and its roughly 50F (10C) or below you can't supercharge until the battery warm up.
    So its best to stay say 10 miles away so your battery warms up before you get to the supercharger (provided you still have
    the range before you go to sleep).
     
    • Informative x 1
  4. mknox

    mknox Well-Known Member

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    Toronto, ON
    In some ways, I don't mind the limit in the cold weather. Here's why:

    Anyone notice how an otherwise clear roadway can have (black) ice buildup beneath underpasses on the freeway? It happens quite a bit around my neck of the woods. Last winter, I was slowing down under re-gen as traffic was slowing ahead of me. As I hit the black ice, the rear end of the car kicked out as it lost traction due to the braking effect on the rear wheels (I have a RWD S85). It regained composure as soon as I hit the dry pavement on the far side of the underpass, but those 2 seconds were pretty scarey.
     
  5. kort677

    kort677 Active Member

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    what is the big concern about when regen braking kicks in? it only takes a few miles of driving for the battery to become warm enough to allow regen.
     
  6. EdA

    EdA Model S P-2540

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    I think you want to be in more control of when braking occurs when you're driving on ice.
     
    • Like x 1
  7. ravejads.tmc

    ravejads.tmc Member

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    When you say a few miles, could you clarify and is this starting with below freezing ambient? Are you able to plug in during the day?

    I'm in NH and this is my first winter with the car and I am finding that it takes about 30 miles before the regen is fully functional on my drive back home. I don't have any way to keep the car warm at work so it's pretty cold by the time I leave work. I do preheat the cabin (very handy) but that doesn't seem to change the behavior of the regen.
     
  8. EdA

    EdA Model S P-2540

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    Until you get charging at work or until Tesla adds a pre-warm option to the phone app you're going to have to get used to it. Are you driving at highway speeds on your way home?
     
  9. ravejads.tmc

    ravejads.tmc Member

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    Mostly highway. Rt 89S from Hanover.
     
  10. tga

    tga Supporting Member

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    If you park in the Hanover town garage or hospital garage already, you could move to one of the J1772's on cold afternoons, top off and pre-warm the battery.
     
  11. ravejads.tmc

    ravejads.tmc Member

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    I knew about the chargers in town garage (I have parking around the corner) but per kwh they are more expensive than charging at home so unless the battery is going to be damaged I would use that just in an emergency. I didn't know the hospital had chargers, I'll have to check them out.

    Of course I can always go home via 91S to 89S and hit the SC in West Lebanon for a quick warm up and charge if needed. I expect when it's below zero I may choose that option.
     
  12. tga

    tga Supporting Member

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    4 30A Chargepoints ($1/hr + parking fee) in the town garage, 2 16A and 2 30A in the hospital garage (free, I think), and 2 16A at the DMHC office on Heater Rd (also free, I think).
     
  13. Gregkeys

    Gregkeys Member

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    How can you tell if Regen is working or not, I see it drop to green on the gauge and feel the obvious slow down, but I haven't seen it add any miles to our battery yet, we've had our Tesla for about 2 weeks.
     
  14. AB4EJ

    AB4EJ Member

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    If you feel the slowdown, it is working. I noticed regen turning off the first time today (first really cold weather since I got the car) - it seems to revert to working like a ICE transmission. (This can also be selected in settings, minimal regen).

    On power on the car, what I think I noticed is that the arc that usually shows regen amount turns to a dotted yellow line; there was also a brief display of a little caution icon.
     
  15. SMSMD

    SMSMD Active Member

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    20161219_150133.jpg
    You can also see the doted line as shown in the image. ..
     
  16. SMSMD

    SMSMD Active Member

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    20161219_151817.jpg Regen back on after driving. .the dotted line is gone
     
  17. Gwgan

    Gwgan Almost a wagon

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    The only time I've seen the battery percentage increase during regen was going down Cadillac Mountain. Steepest ascent/descent that I've experienced so far. Mountain drivers could probably tell you more stories, but i know it does happen.
     
  18. Sather

    Sather Member

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    It definitely goes up on a longer downhill.
     

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