Hill Driving Question

Discussion in 'Clarity' started by dubu_x, Dec 18, 2018.

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  1. dubu_x

    dubu_x New Member

    In my everyday commute, I have to drive up and down a hill that is about 2 miles long. I honestly hate driving up the hill because it kills my EV range and I feel like I'm pushing my car. I also get stares for driving slowly up the hill sometimes. So my question to you guys is, do you know if it's better (or do you prefer to) drive speed limit (65mph) going up hills, or do you drive slowly up hills? Which is better for EV range?
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  3. David Towle

    David Towle Well-Known Member

    The most efficient speed for a gas engine car is typically around 50 mph, the point where wind resistance starts to become significant. Its a tradeoff of the engine itself becoming more efficient with higher speed as the percent of power needed to counteract the wind resistance goes up . That's not the case with EVs so I bet the most efficient speed is more like 30 mph.

    But of course going that speed doesn't do you any good if you get run over by a truck and are dead.
  4. jdonalds

    jdonalds Well-Known Member

    Just a guess but I'd say driving the speed limit is best. The main thing is not to accelerate when going uphill.
  5. MNSteve

    MNSteve Well-Known Member

    I doubt that wind resistance has that big an effect, but you could try to measure by noting your EV range at start and end and then making the ascent at different speeds. With only a two-mile hill you're going to need to have to do multiple samples to come to any conclusion, and even then it may not be accurate given that EV range is reported on in whole-mile units.

    I'm a flatlander but my personal philosophy is that I am unlikely to modify my driving habits in the name of improving EV range. I bought the car to be comfortable in terms of both temperature and not causing traffic disruption, so I don't go without heat and I drive at the speed that I think is appropriate.
  6. neal adkins

    neal adkins Active Member

    What i do is select sport mode and hv. This allows you to save some ev range. I slightly build my speed up before entering the upgrade when possible and try to stay close to the speed limit as i climb the upgrade, but allow a little deceleration. The idea is to flow with traffic for safety and allow the ice to work in tandem with the electric motor to save your ev range.
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  8. insightman

    insightman Well-Known Member Subscriber

    It makes sense to use HV mode going up hills to provide an extra 60 horsepower and it will try to preserve your battery's state of charge. However, I don't see any advantage of using SPORT Mode other than not having to press the accelerator as far to go up the hill at a given speed.

    As you may have experienced on bicycle rides, going up a hill slowly requires less power than going up a hill quickly. For a given speed, ECON, NORMAL and SPORT Mode will all use the same amount of power going up a hill (with the asterisk that ECON Mode can save power by moderating the air conditioner). HV Mode (in concert with any of these 3 different accelerator-mapping modes) lets you choose to use primarily ICE power instead of battery power.
  9. I'm tending to engage the ICE when going up longish hills too. It depends on how close I am to home and the EV range.

    Related questions:
    1. When should you start the ICE? Well before the bottom of the hill, so it has a chance to warm up a bit or right at the bottom?
    2. Should you enter HV Mode explicitly with the push of its button? Or simply depress the gas pedal past the click?
    3. I have a 50 mile or so round trip where the "to" tends down hill, while the "back" tends up hill (of course). I have be using EV for the first half and then engaging the ICE on the way back. Does this make sense?

  10. insightman

    insightman Well-Known Member Subscriber

    1. The ICE with its 0W-20 oil will warm up quickly enough for the task at hand no matter when you fire it up. I learned in my gen-1 Insight to gather as much speed as is safe (and not near speed-trap zones) before hitting the start of the upcoming hill.

    2. You must select HV Mode to get the AI benefits of that mode. Activating the ICE with the accelerator pedal simply gives you an additional 60 horsepower until the ICE has run long enough to consider itself warmed up, or as long as you continue pushing the Power/Charge into the solid white arc.

    3. I use ECON Mode (some consider this EV Mode, but it's more like EV-Preferred Mode) in town and then switch on HV Mode on the e-way. When I'm within EV range of a charging station, I switch HV Mode off. I'm disappointed in my estimating skills when I return home with more than 5 miles of EV range remaining.

    3 with an asterisk. If my wife calls me while I'm cruising around in her Clarity to warn me that she's going out after I get home and the battery had better not be dead when she takes over her car, I use HV Mode all the way home. In one extreme case I had to engage the dreaded HV CHARGE Mode all the way home.
    Last edited: Dec 20, 2018
    Randy Stegbauer likes this.
  11. KentuckyKen

    KentuckyKen Well-Known Member

    @insightman, if you ever mess up and give your wife her Clarity back with a dead battery...we’ll miss you on the forum, RIP.
    David Towle, MNSteve and insightman like this.
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  13. PHEV Newbie

    PHEV Newbie Well-Known Member

    You only get the extra horses with a charged battery. If your battery is depleted, the car's software will rely on the ICE to generate electricity and not draw from the battery to avoid harming it. That happened to me once going up a mountain grade near my town and it was just awful. The ICE was screaming and I had to stay in the right lane with the semi trucks. All the other times, when my battery was at least 60% charged, I could fly up in the left lane with the ICE purring quietly because the traction motor was drawing from both that and the battery. Whenever I go on any long highway stretch, I switch to HV as soon as my battery drops to about 80% so I know I can get the full 181 hp if necessary.
    Last edited: Dec 21, 2018
    insightman likes this.

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