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Last mile EV... your thoughts

Discussion in 'Gen 3 Prius Main Forum' started by lamontcranston, Sep 17, 2009.

  1. lamontcranston

    lamontcranston Umbra Tenet

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    I know this has been discussed before, and I know what was said. I've had different results, and perhaps I'm just "special."

    The last mile of my commute is all uphill with three stop signs. This also means that the first mile of my commute is all downhill with three stop signs.

    It's been said that using EV for the last mile is actually worse, because the car needs to use extra energy to recharge the battery in the morning when it's least efficient.

    Except, I seem to have better results from using EV for the last 5/8 mile or so (so that the engine stays off all the way into the garage.) In the morning, I get a lot of regen braking and coasting because it's all downhill. So the ICE is on anyway, but MPGs are pretty high (30-40) and the battery is back to 5 bars before I get to level ground.

    Is mine just the exception that proves the rule?
     
    #1 lamontcranston, Sep 17, 2009
  2. efusco

    efusco Moderator Emeritus
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    I think that's fine, and probaby a logical use of EV. Here's why...you're downhill in the morning, so you don't need to really 'borrow' battery power.

    If you had a Scan Gauge or CAN-View I'd recommend that, in the morning, that you just be careful to keep your RPM below 1300 until S1 is complete and to make sure your amp draw was less than about -15 during that same time...indeed, going downhill, you may be able to have a positive amp read and be charging the battery a bit.
     
    #2 efusco, Sep 17, 2009
  3. JRitt

    JRitt Bio-Medical Equip. Tech

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    The last 1.1 mi of my drive is slightly up hill in a residential neighborhood (max speed 25mph). I do this in EV to partialy deplete the battery because in the morning I go down the hill that when warm is all battery and low current draw (I lose only 1 bar for the mile+) but when the engine is cold it has to run anyway to war up the cat. converter so I might as well let it charge the battery.
     
    #3 JRitt, Sep 17, 2009
  4. a64pilot

    a64pilot Active Member

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    I would think that if you have tried it, and it worked, then it worked. I tried it, I live on dead flat ground and it didn't work for me, but I live on dead flat ground.
    Or for every rule there is an exception, I think your case is an exception.
     
    #4 a64pilot, Sep 17, 2009
  5. qbee42

    qbee42 My other car is a boat

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    Obviously, if your morning downhill contains more energy than your HV battery can take in its nominally charged state, it makes sense to run down the battery a bit on the evening uphill. How much will depend on your exact circumstances. Do a little experimenting and see how much battery you need to take the whole downhill regen. Aim for that as your target SOC at the end of the day.

    Tom
     
    #5 qbee42, Sep 17, 2009
  6. lamontcranston

    lamontcranston Umbra Tenet

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    That's a good idea. As I said the battery hits 5 bars by the time I get to the bottom of the hill so perhaps I need to use a little less battery on the way home. Great advice!
     
    #6 lamontcranston, Sep 17, 2009
  7. a64pilot

    a64pilot Active Member

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    Only question I have is I have always been taught that you should not leave a battery discharged. Just wonder if putting it to bed with a low SOC would over a long time shorten the battery life?
    Me, I want to use EV for the last two miles and then charge the battery overnight. I can get two miles merely maintaining speed. It's not much, but it's two miles
     
    #7 a64pilot, Sep 17, 2009
  8. MikeDS

    MikeDS Member

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    My understanding is even when the Prius's SOC looks empty, in reality the battery is still are 40%, or something like that. I remember reading how the Prius never charges all the way to 100% or discharges all the way...part of extending the battery life.

    Plug-in over night would be awesome...kinda thought I was gonna get that when I was buying a Gen III, haha...
     
    #8 MikeDS, Sep 17, 2009
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