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observation

Discussion in 'Gen 2 Prius Fuel Economy' started by Tadashi, Jun 7, 2005.

  1. Tadashi

    Tadashi Member

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    Lately I have noticed that if I try to drive the last 3-5 miles so that I wear the battery down to 2-3 bars (which usually gets me about 0.1-0.3 mpg increase). It increases my fuel economy because when I start the car back up to go home the ICE spools up to warm up. The fuel economy is always the same about 40 mpg for the first 5 min whether my battery is fully charged or down at 2 bars. I figure the engine is recharging the battery while it warms up, instead of just reving up and wasting the energy.

    This is ideal for me since the last 5 miles of my trip is on rural roads, very few stops, and flat. I can drive up to 25 mph without the ICE kicking in if I do it right. I rapidly accel to 25 take my foot off the pedal and when the ICE shutsdown lightly press the accel to maintain the 25 mph (which is the post speed limit).

    0.1-0.3 increase sounds small but over a week it adds up. Now that I am at the end of the tank (400 miles) I am only getting about a 0.5 net increase for the week. :( I am at 59.4 and still have 3 bars left. I am hoping to break 60 before I have to fill up. :lol:
     
    #1 Tadashi, Jun 7, 2005
  2. rcroft

    rcroft New Member

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    Many people here seem to view the cruise control with contempt, but I have found that on the flat slow roads that you describe, the cruise control is very good at using only the electric motor to maintain speed.

    You don't even have to do the rapid accel and then take your foot off the gas thing. Just set the cruise control to the speed you want, and if you are doing about 35 or under, it will switch to using the electric motor only within a second or two.
     
    #2 rcroft, Jun 7, 2005
  3. Tadashi

    Tadashi Member

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    i use cruise as much as possible but anything below 24 mph and cruise will not set. However, when I use cruice at 24-25 it uses the ICE more than if I use a light foot. Cruise will only get the bars to about 5 where as I get it down to 2. This is then recharged when the car warms up. I am not sure if this will create a battery lifespan issue by doing this.
     
    #3 Tadashi, Jun 7, 2005
  4. Tideland Prius

    Tideland Prius Moderator of the North
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    No idea but I do that sometimes too. I'd figured why not let the engine charge the battery while it's warming up. However, I don't tend to run it down to 3 bars because most of the time, I'll have to go up my alley rather than down. Leaving 4 or more bars allows me to get up that alley on battery and letting the engine do its thing. If the battery runs down too quickly, the engine will chip in earlier. Note, during the warm up period, you're still using mostly battery power. When you press harder, you don't hear the engine rev.
     
    #4 Tideland Prius, Jun 7, 2005
  5. rcroft

    rcroft New Member

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    <div class='quotetop'>QUOTE(Tadashi\";p=\"96375)</div>
    I've never tried using the cruise control at around 25 mph. However, the last 2 miles or so of my commute is on a 30 mph flat road. There's just one little rise where the ICE comes on, but then it switches right off.

    I've never been very good at maintaining speed with electric only when I'm using my foot. I can get it to show that it's only using the electric, but my speed still creeps down over time, and then when I try to give it just a little more, then the ICE kicks in. Once I discovered that the cruise control did a far better job than I did at low speeds, I stopped looking at the screen and listening for the engine, and started paying attention to the road.

    Most of my commute is hilly and I can't really use the cruise control. It does OK on the shallow hills, but I have a lot of steep and sudden hills where the cruise control revs the engine way up to maintain speed, while I can tolerate a 2-3 mph drop in speed on the way up and make it up on the way back down.
     
    #5 rcroft, Jun 7, 2005
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