Mountain driving

Discussion in 'Clarity' started by JimW, Apr 3, 2018.

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  1. JimW

    JimW Active Member

    We took a long weekend driving across the Smoky Mountains. A few observations:

    -Climbing a mountain in EV mode uses battery very quickly. On the other hand, coming down the mountain, we actually generated more electricity that we used. Running in EV mode the entire way down (~29 miles), my EV range increased from 11 to 39. This is a combination of adding charge to the battery (from 0 to 50%) and the KW/mile number becoming very low. I wonder how the car handles the EV range calculation when the KW/mile is a negative number? In theory, the range could be infinite since the car does not know how long you will be going downhill.

    -On a long trip in HV mode, it is best to maintain the battery charge in 40-60% range. With zero EV range (2 bars showing), the engine sounds like a swarm of bees while going up a long grade. My wife kept asking what's wrong with the car? It makes for a very unpleasant driving experience. With 50% charge and going up same hills, you hear the ICE, but the sound is more like a normal car engine and nowhere near as annoying.

    -The Clarity handles surprisingly well on mountain roads, but the eco-tires are not up the task of turning all that weight. I think a good set of more performance oriented tires would help a lot. I wonder what the impact to range would be?

    -This morning after full charge overnight, my EV range was showing 59.5, the highest it has ever been. (Previous high was 45.) I know it is warmer today, but the car must be remembering the low KW/mile number from driving down the mountain, even though the car drove 100+ miles in HV mode on highway after that.

    Question for Volt owners - after the battery is depleted and you are climbing a mountain, does the engine sound like the Clarity does?
    PHEV Newbie and kkiran like this.
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  3. Volt owner here (first generation). The engine does get very busy in the circumstances that you describe.

    The Volt equivalent to HV Charge mode is called Mountain mode and you're specifically instructed to use it in advance of long steep grades (say, 20 minutes in advance). In the Volt the Mountain mode goal is 50% charge.
  4. JimW

    JimW Active Member

    Just to be clear, coming down the mountain I was in EV mode (not HV Charge). I used the paddles to control my speed, and the regen energy charged the battery.

    I did not try HV mode while going downhill, but I expect the ICE would have turned off as the engine power was not needed.
  5. lorem101

    lorem101 Member

    Has anyone experienced what's described below?
  6. Viking79

    Viking79 Well-Known Member

    The car weighs 4000 lbs and only has a 100 hp gas engine, if the battery is depleted that is very under powered for interstate highway travel speeds in hilly terrain. I do think engine or battery management could be improved, as I am not a fan of angry buzzing either. I think it selects that RPM for efficiency.

    Performance tires will vary, but your range will probably take a hit of 10 to 20%. Trade-offs. I put high performance all seasons on my Volt and range dropped about 10 or 15%.

    Thanks for the feedback about mountains, I won't be driving in any until later this year or sometime next. Nice to know what to expect.
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  8. ManKo

    ManKo Member

  9. Schaffer970

    Schaffer970 New Member

    Have done very much the same as you described. Try using cruse control while coming down the mountain. I have found that this works better than using the paddles. One very nice feature of cruse control is that it maintains a constant speed whether going up hill or down. My best EV range is on the attached picture which I attribute to the downhill run before charging. :D EV 70 Mile Range.jpg

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