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Does the range ever go up during regenerative braking?

Discussion in 'Model S: Battery & Charging' started by pete8314, Jun 27, 2014.

  1. pete8314

    pete8314 Vendor

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    I think I'm wasting my time, but on my daily commute I have a long, downhill section that typically is fairly quiet, so I get a really prolonged shot of reclaimed energy (~70mph to ~5mph) back into the battery, and constantly hope to see the range go up by a mile. It never does, even if it just dropped, so I guess it never does, no matter what? I get that you don't want it flitting up and down all the time, but just every now and then would make me feel better :)
     
  2. SummerlinModelS

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    I've read (and experienced) that the range doesn't go up mile by mile. Rather, once you have regenerated a full kWh it will go up 3 miles at that point. I have seen that happen and even watched as it regenerated a second kWh on a long downhill I've taken.

    If you watch your range after the you've resumed using power you'll notice that it takes longer for the range to actually go down proving that you had added some energy back to the battery--it just doesn't register these small increments of addition in the range number.
     
  3. AnOutsider

    AnOutsider S532 # XS27

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    It's been a while since I've watched for this, so it could have changed in subsequent FWs, but I've seen it go up. It doesn't go up right away though, it's almost as if it recalculates on a schedule (whether based on time, or distance moved etc)
     
  4. Zextraterrestrial

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    still only 3 mi increments in 5.9 (~1kW?)
     
  5. Lloyd

    Lloyd Active Member

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    Doing down Cuesta Grade just North of San Luis Obispo, you can easily gain 3 to 5 miles from top to bottom.
     
  6. Merrill

    Merrill Active Member

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    I live on a hill and it is 2 miles down, usually gain 3 miles unless the car is fully charged. You will not gain miles if you just completed a charge. If my charge completed hours before I leave and has lost some mile to vampire it will gain when regenerating.
     
  7. plaeuschler

    plaeuschler Member

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    #7 plaeuschler, Jun 27, 2014
    Last edited: Jun 27, 2014
    On mountain top (after somewhat aggressively zipping around the corners :), and after going down about 800m (9km drive)

    zysygesy.jpg

    a3ameben.jpg

    With metric setting it does 5km steps while regen charging, which would match the 3mi jumps mentioned earlier.
     
  8. spaghetti

    spaghetti Member

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    Have gained 6 miles each time I have gone down the Grapevine in SoCal going Northbound.
     
  9. pete8314

    pete8314 Vendor

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    Cool. I need to head out to those Texas mountains then....hmmmm....
     
  10. Cottonwood

    Cottonwood Roadster#433, Model S#S37

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    The jumps are in 1 kWh increments, which usually gives you 3 mile increments, and sometimes 4. If you bring up a trip screen and look at the kWh, and notice when you start down hill, you will see that the increment comes when you have accumulated 1.0 kWh. As others have said, if you get less than 1.0 kWh, then the kWh will decrement back to where you were, before any more miles are shown leaving the battery.

    Eisenhower Tunnel to Silverthorne is a regular 6-7 mile (2 kWh) range increase, and Wolf Creek Pass into Pagosa Springs is a regular 10 mile (3 kWh) winner.
     
  11. plaeuschler

    plaeuschler Member

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    Ok, as a summary: That means you need to regen at full power (60kW) for a full minute to see the effect on your range. (or 30kW for two minutes without interruption). It probably won't even be enough regen when slowing down from 210km/h because that doesn't take a minute on a flat stretch.
     
  12. 4SUPER9

    4SUPER9 Active Member

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    Coming down from Lake Arrowhead, I typically have a net gain of about 20 miles after traveling downhill for 20 miles or so.
     
  13. ZBB

    ZBB Emperor

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    Here's a pic I took at the bottom of the Yarnell Grade in AZ...

    That grade drops ~2000 feet over 4 miles. I had driven a few miles after charging for a bit on 120V when visiting family in Yarnell. It picked up 3 miles on the way down. Wh/mi was negative over those 6 miles!

    attachment.php?attachmentid=50223&stc=1&d=1401123466.jpg
     
  14. brianman

    brianman Burrito Founder

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    Here's a data point for you.

    At the top of Mt St Helens (tourist viewpoint), I had 11 rated miles. At the bottom, I had 15 rated miles.

    (Yes this was cutting it uncomfortably close.)
     
  15. DITB

    DITB Charged.hk co-founder

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    As long as you don't have a full charge, or a too hot battery - how steep can you descent without using the brakes at all? Let's just say maintaining a speed of 55 mph?

    Is there any difference if you let go of the accelerator with normal regen, or set the cruise control to 55 mph?
     
  16. Cottonwood

    Cottonwood Roadster#433, Model S#S37

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    I don't know exact numbers, but I've gone down a lot of steep hills in Colorado (I've tried up to 16%, 9˚) and I have not met a hill that regen couldn't maintain speed on. I am sure that it would work on steeper.

    Cruise control will use max regen when it needs it. The regen is limited to 60 kW on my 85; above about 45 mph, it's a constant 60 kW (less force at higher speeds), and below about 45 mph, it is linear with speed (a constant force). Remember that power is force times speed.
     
  17. brianman

    brianman Burrito Founder

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    For a 10°, starting at 50mph (speed limit 45mph) I've had to use the brakes to keep it below 55mph.
     
  18. nwdiver

    nwdiver Active Member

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    Where did you find a 10 degree hill?
     
  19. Cottonwood

    Cottonwood Roadster#433, Model S#S37

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    Was regen on "normal?" That is very important to keep the speed in check.
     
  20. brianman

    brianman Burrito Founder

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    Sorry, I meant 10% grade.

    10PercentGrade.png

    N/NW on Sahalee Way, Sammamish, WA.
     

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