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Exactly How Strong is the Regen?

Discussion in 'Model 3' started by ZeApelido, Jan 6, 2018.

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  1. Zoomit

    Zoomit Member

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    Everytime I drive my Model 3, I’m disappointed with how weak the regen is compared to my wife’s Bolt EV. It’s easily my biggest disappointment with the car.
     
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  2. Randy Spencer

    Randy Spencer Active Member

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    That's funny, my wife's iMiev now has less regen in the B mode than the RWD TM3. After the update I like sitting in the Tesla more, but it wasn't always that way.

    -Randy
     
  3. ℬête Noire

    ℬête Noire Active Member

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    The only thing I miss compared to the Bolt is that last few feet, where brake pedal is optional on the Bolt.

    I don't think the regen is actually weaker on the LR-D, it just feathers in smoother so you don't get that initial jerking sensation as the Bolt 'L' regen comes at you a lot faster. I find the LR-D to be the preferable ride & handling but obviously that's personal preference.
     
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  4. Zoomit

    Zoomit Member

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    My LRD has obviously less regen deceleration than our Bolt EV to me. I don’t know about the amount of regen power generation but the deceleration is less than the Bolt in L mode and certainly less than L+paddles (ROD). It’s more than in D mode. This is all according to my uncalibrated rear-end, no hard data.
     
  5. ℬête Noire

    ℬête Noire Active Member

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    The data of relatively modest providence, where they had a g-meter of some sort onboard the Bolt (one of the magazines, don't recall which one) pegged it as the same. They had the RWD somewhat below. The AWD variants weren't out yet at the time but the g has since been measured for it (and stated by Tesla). They didn't do a full analysis of the curves though, it was pretty rough data with only a few points. It is really easy for butt dyno to be off on the sensation when you've got such a different onset.

    The paddle I believe does push the regen above the LR-D by the 15% or whatever it is that it adds to 'L'. That's a kinda good feature. I rely on it more for a way to deactivate CC than actual braking in the Bolt, however I do sometimes use the paddle when I misjudge my stop point.
     
  6. Zoomit

    Zoomit Member

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    Was it the data at the beginning of this very thread?

    I've never seen Tesla quantify the regen deceleration. Do you recall where you saw that?
     
  7. ℬête Noire

    ℬête Noire Active Member

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    Tesla themselves have mentioned it before in regards to Track Mode, to try hang numbers on how much stronger that is. "0.2g" for Normal, "0.3g" for Track Mode.

    I'm trying to find it but don't see it now; There was someone that managed to get into factory mode with the RWD to confirm it was set to about 47kW max regen. That along with the known Bolt regen kW (because you can see it on screen) and modest mass difference, line up fairly well with those numbers in that chart (well after it is corrected, they made a boo-boo when it was first published). Note that the Bolt EV limit on regen is more affected by where you are with SOC, because they are pushing up harder against their battery limits.

    Really those g numbers are kinda laughably simplified because of the way they are shown on that chart because it's really the kW that are closer to straight lines. Since kinetic energy is a function of the sq of the speed (and linear with mass), the effective g at highway speeds from regen ends up being a lot lower. Of course the Bolt will feel like more deceleration from highway speeds when you let off because you're also feeling air resistance, which is a good deal higher up there.

    I'm not sure if you've ever driven the RWD LR? But it is a world of difference on the regen with it compared to the AWD. That's why I completely buy an extra 0.05g (although the RWD regen has gotten a boost since I last drove it). Unfortunately I haven't seen anyone put an AWD into Factory Mode to hard confirm its kW. Is that still possible or did Tesla patch out the exploit? However, setting aside the jerking motion and the first maybe 1/4 second of onset, I find my Bolt judgement overlaps with the AWD judgment in mid-range speeds.

    P.S. The Model 3 has actually spoiled me. Because I don't drive the Bolt near as much a the Model 3 I'm not quite as good any more at mitigating the jerkiness with foot control. I still have some of it because I'm working on better Model 3 control but actually doing it to feather in regen at lower speeds on the Bolt isn't instinctual for me anymore.
     
  8. Zoomit

    Zoomit Member

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    I was able to do a little testing this evening with both cars.

    Model 3 LR AWD
    - Battery: 60% SOC and fully warm
    - Regen: Standard

    Bolt EV
    - Battery: 80% SOC and driven 7 mi in 50F temps
    - Regen: L mode and L+Regen On Demand paddle

    I tested deceleration distance from 70mph to 5mph. I did 2-3 runs each with repeatable results. The run-to-run dispersion and measurement error is probably +/-30 ft. The model I created a few years ago, and mentioned upthread, predicts:

    Bolt EV L mode: 874 ft, average 0.20g, peak 0.23g
    Bolt EV L+ROD: 672 ft, average 0.26g, peak 0.30g

    I measured:
    - Bolt EV L mode: ~900 ft
    - Bolt EV L+ROD: ~750 ft
    - Model 3: ~900 ft

    So both cars stopped very close to each other, ignoring the ROD paddle capability in the Bolt EV. The Bolt's analytical model was pretty close so I'm fairly confident that the average deceleration over the 70-5 mph range was ~0.2g. The L+ROD paddle on the Bolt EV provides noticeably greater deceleration and shorter stopping distance.
     
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  9. ℬête Noire

    ℬête Noire Active Member

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    TLDR; "Yeah ℬête Noire, you were right". :D

    The jerky onset of the Bolt's L regen gives the false impression it is "stronger" but in actuality overall L (sans whammy-bar) is the same regen braking as LR-D. Just a somewhat different shaped curve.
     
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  10. Sunshine State

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    #90 Sunshine State, Feb 12, 2019 at 8:49 PM
    Last edited: Feb 12, 2019 at 8:55 PM
    We have three AWD Tesla’s, two S’s and an X, and my son also has a RWD Tesla S75. His RWD S75 has less regen than the AWD S and X which seem about the same. A week ago we test drove a P3 and that seemed to have much less regen than the bigger AWD’s, probably close regen to the RWD S75. Quite a while ago we drove YouYou’s RWD long range 3 and that had significantly less regen than any other Tesla we have driven. Disclaimer, I have never driven any Tesla older than a refresh S so I’m not sure what the older ones are like. I also used to have a BMW i3 REX, that had very nice regen all the way to a stop. The regen to a complete stop caused you to never use the brake except for an emergency stop and at that point the rusty brakes sounded bad. An interesting feature of the BMW i3 was that in extreme handling situations regen was cut down to prevent loosing rear traction in a corner.
     

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