Regenerative Braking Capacity

Discussion in 'Prime Technical Discussion' started by KyleSTL, Jul 15, 2016.

  1. KyleSTL

    KyleSTL Junior Member

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    Out of curiosity, does anyone know how the following models compare regarding maximum regenerative braking (in kW or other power unit of measure):

    2017 Prius Prime
    2012-2015 Plug-In Prius
    2016 Prius
    2016 Prius Two
    2010-2015 Prius

    I was wondering if the plug-in models have a higher regenerative braking ability since the overall battery capacity is greater (than non-plug-in models) and therefore an equal energy flow would be a smaller percentage of its energy capacity (i.e. lower C rate for the battery).
     
  2. Trollbait

    Trollbait It's a D&D thing

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    Battery capacity is the limiting factor, so the Prime should have the highest, but we'll have to wait for someone to test drive one with a Scangauge or such.
     
  3. KyleSTL

    KyleSTL Junior Member

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    A quick search did not find it, but how did the previous generation PIP compare to the liftback? Or the new Prius vs. the Prius Two (with the NiMH battery)?
     
  4. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    2017 Prius Prime This car does not exist, it is unlikely that anyone knows, certainly no one outside of Toyota in Japan*
    2012-2015 Plug-In Prius 2000 foot drop to fill battery going downhill
    2016 Prius
    2016 Prius Two
    2010-2015 Prius 600 Foot drop to fill battery going downhill

    *recent 'first drives' only involve prototypes, not production models.
     
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  5. fuzzy1

    fuzzy1 Senior Member

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    The 2010-15 Liftback has a battery power limit of 27 kW under best conditions, reduced under various other conditions.
     
    #5 fuzzy1, Jul 15, 2016
    Last edited: Jul 15, 2016
  6. bisco

    bisco cookie crumbler

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    maybe you can find it in the sae papers for pip and lift backs.
     
  7. drash

    drash Senior Member

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    First try Advanced Vehicle Testing Activity . Shorthand for Advanced Vehicle Testing at the Idaho National Lab. They have lots of detailed info on just about every EV, PHEV, and hybrid ever tested but not every model year. Caution though, its a PITA of a web site just to get around in. All of their testing of vehicles is done in Arizona.
     
    #7 drash, Jul 18, 2016
    Last edited: Jul 18, 2016
  8. Tideland2005

    Tideland2005 Member

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    The 1.7kW/hr battery in my Gen2 will fully charge in about 300' of drop.
    It wastes anything in excess.

    I think the Prime 8.8kW/hr battery will work very well in greater LA, where the climbs
    and descents are roughly 900'. Looking forward to it.

    Cheers, Steve
     
  9. drash

    drash Senior Member

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    Since the EV mode locks out the ICE for dual motor use, do both motors also contribute to regen when braking? Hard to tell from all the first drive articles I read. Seems they just want to talk about the old PiP disabilities versus the Prime.
     
  10. fuzzy1

    fuzzy1 Senior Member

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    MG1's participation in regeneration (or anything else) is limited by the ICE torque. When the ICE is stopped, and not mechanically locked -- something I've never heard of in any Prius -- MG1 is in no position to do any regeneration.
     
  11. elman1

    elman1 Junior Member

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    any update on the prime in this respect ?
     
  12. drash

    drash Senior Member

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    I'd have to say it's probably close to the 23 kW rating of MG1 using either regen braking or Charge mode. Although the Gen 1 Plug-in Prius has a 42 kW MG1, the battery electronics was only capable of handling 38 kW. I'd have to look through my data to see what the maximum recorded on OBD II.

    After looking through some of my data, the most I've seen going back to the battery was just shy of 133 A. Works out to be about 27 kW.

    Unsupervised!
     
    #12 drash, Jan 3, 2017
    Last edited: Jan 3, 2017
  13. jaqueh

    jaqueh Active Member

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    Has anyone been able to figure out the Primes braking ability? Regen braking on this car seems to be really weak for a partial EV. Mg1 can only handle about 40 pound feet of torque. That is not a whole lot of braking force.

    I ask because it seems really difficult to modulate regen vs friction braking with the pedal and the charge portion of the drive monitor doesn’t help much in that aspect either as it is dependent on speed instead of capacity.

    My friend just got an i3 and it has one pedal driving. When he let’s go of the accelerator, the car goes into an almost panicked like braking and slows the car down at least with 4x as much power than the prime.

    Why didn’t they introduce a larger motor for braking in the prime? Why didn’t they make the drive monitor more effective in telling how much further down you can press the pedal for regen?
     
  14. Mark57

    Mark57 2021 Tesla Model 3 LR AWD

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    I'd hate that and it seems dangerous with the way people's minds drift. Toe cramp . . . damn, just got rear ended.;)
     
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  15. Trollbait

    Trollbait It's a D&D thing

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    That's what cruise control is for :)
     
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  16. fuzzy1

    fuzzy1 Senior Member

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    I don't yet have a Prime, so can't fully answer your questions. But with respect to previous generations:
    MG2 does much of the regenerative braking in Gen1-3, and all of it when the ICE is shut down. Please don't tell me that Gen4 doesn't use MG2 for this. :-(
    That speed dependence is a direct result of basic physics. Braking power equals braking force times vehicle speed, so when the limitation is the battery power capacity, then the available braking force changes with speed.

    Gen3 non-Pip has a battery power limit of 26kW under best conditions. Neglecting lossy conversions within the system, this corresponds to 174 pounds of braking force at 75 mph, 327 pounds at 40 mph, or 654 pounds at 20 mph. While slowing down, this changing (increasing) force capacity does show up on Gen3's HSI display.
     
  17. jaqueh

    jaqueh Active Member

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    I understand that but I wish they made the regen portion of the graph more like the acceleration portion. Because energy usage bar doesn’t get smaller the faster you go. It’s directly related to how much the motor is being used rather than how much energy is being used.
     
  18. fuzzy1

    fuzzy1 Senior Member

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    I don't see how the change you wish is compatible with the concept of the driver trying to track the changing threshold of maximum regenerative braking while staying out of friction braking.
     
  19. jaqueh

    jaqueh Active Member

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    I see what you’re saying. I just think that there is a lot of confusion in regards to what the indicator does. Check this.

    I just wish that the charge graph just indicated how much the electric motor could be used at all speeds instead of how much energy goes back to the system with the bottom of the bar being higher speed regen.
     
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