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One purple battery bar left with a 1000' climb to go....

Discussion in 'Gen 2 Prius Main Forum' started by moredes15, Jan 3, 2007.

  1. moredes15

    moredes15 Junior Member

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    Climbing the Guadalupe Mtns towards Carlsbad Caverns, I monitored the MFD's battery estimate at 1 purple bar at 4700'. The Garmin GPS's elevation estimate topped the mountain route I took at ~5800'.

    I'd read here that folks have taken the Eisenhower Tunnel and the Tehachapis with "no problem" but 1 purple bar had me wondering... but with less than 6000 miles on this new car, I thought--well, this is the time to find out--it'll be warrantied if I'm stuck here. Aside from a whining engine that sounded like I was whipping every squirrel one at a time, there were no problems. I must admit to turning off the radio, climate control, MFD and dimming the dash lights at around 5000', but nothing seemed amiss though it sure took a long time to recharge the next time I started up the car. It ran on open flat ground on two blue bars the next morning for over 110 miles before it 'started charging', though it was averaging ~39mpg over that drive.

    I've seen one and two blue bars before, but this is the first time I've seen purple. Was there any reason to worry? A 'Search' here doesn't seem to find any problematic incidents, but most purple (and pink) bar complaints come from commuters stuck in traffic.

    Thank you.
     
    #1 moredes15, Jan 3, 2007
  2. TonyPSchaefer

    TonyPSchaefer Your Friendly Moderator
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    When the battery is "drained" on the MFD it's really around 40% charge. Guys, someone provide the real numbers here.

    When there's a continuous draw on the battery such as high mountains, the Prius will, of course, try to recharge, but with the constant pull on the engine, it will not be able to. At that point, the Prius - for all sakes and purposes - becomes a regular car.

    There is no concern for breaking the car.
     
    #2 TonyPSchaefer, Jan 3, 2007
  3. Presto

    Presto Has his homepage set to PC

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    The computer will protect the battery however it can, so there's no need for concern. In regards to running your battery down to purple on the climb, let off the gas a bit and try to maintain a constant speed rather than powering it up the mountain. Flooring it in the Prairies does the same thing to the SOC if the pedal stays on the floor long enough.

    When you say it 'started charging' on flat ground after 110 miles, do you mean there were no orange arrows displayed on the MFD for that long or was it at 2 blues for 110 miles? It's a problem if you didn't see orange arrows, but it's safe to assume that you did since the SOC would drop to critical if it wasn't able to charge for that long. Just learn to ignore the SOC. The computer will take care of it. Charging depends on several factors and one of them is how much the gas pedal is pushed down. Let off the gas so that you see the orange arrows, and you can still maintain speed. Cruise control is pretty good for that.
     
    #3 Presto, Jan 3, 2007
  4. Frank Hudon

    Frank Hudon Senior Member

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    have a look at this site and click on the green ths and it'll take you to the ths11 page so when the battery gets low MG2 ( main electric drive motor ) needs more amperage and the only place that comes from is MG1 and the only way to boost it's output, as it's a permanent magnet motor/generator, is to spin it faster and as you spin it faster the ICE gets to put more load on the planetary carrier which transmits more of it's power to the ring gear which is attached to the wheels. So now on the page set the MG2 slider till you get say 90Kmh (55 mph) which should be about 3200rpm now push the ICE slider till it say's 5000 rpm and note that the MG1 (generator) rpm is at about 10,000 rpm which is it's designed speed limit. Hope this helps a bit in understanding the sequence of events under the hood.
    http://homepage.mac.com/inachan/prius/planet_e.html
     
    #4 Frank Hudon, Jan 3, 2007
  5. daniel

    daniel Cat Lovers Against the Bomb

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    There is no worry at all. Nothing will break. On uphill driving the Prius will draw some energy from the battery while it can. When it is no longer able to, because the computer has decided the battery is as low as it wants to go (where is still has plenty of charge -- but the computer is protecting the battery) then it's got to get all its energy from the gas engine.

    So, bottom line: driving up a long mountain road you're going to burn more gas and your mpg will drop. Once you get to level ground or downhill, it will charge the battery back up again. But around 3 to 6 bars is kind of where it likes to be, so it will try not to charge it all the way up. (8 bars is still only 80% full: protecting the battery again).

    Driving back down that long mountain road you'll see 7 or 8 bars as it absorbs the excess energy through regeneration.
     
    #5 daniel, Jan 3, 2007
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