Low battery = slow acceleration

Discussion in 'Gen 2 Prius Main Forum' started by daveleeprius, May 20, 2007.

  1. daveleeprius

    daveleeprius Heh heh heh you think so?

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    Hi Folks,

    Wife and I just got back from Canada. Our first trip out of the country with our Prius. ^_^

    Filled up before we left, and got home with two pips still on the gauge. Love it. The Prius is by far the most comfortable highway car I've ever driven. Just set the Cruise and go. Wow.

    Anyway, we spent 90 minutes in line coming back into the US at the border. Of course the engine was off while we sat ha ha. The noisy BMW next to us one time was idling around 1k rpm, it couldn't wait to get back on the road probably!

    Anyway, the battery got down to two bars, the lowest I've ever seen it. It didn't go lower. At this point, every time the line moved forward, the engine turned on to charge the battery, but then turned off as soon as I hit the brake.

    When we left the customs guy, the car was accelerating soo sloooww. The electric assist wasn't working according to the MFD. It took us about a minute to get up to 65mph (or so it seemed). The engine was revving high but the car wasn't going much faster.

    Soon after we got to cruise, the battery was charged up and we had a great drive home.

    Dave
     
  2. NoMoShocks

    NoMoShocks Electrical Engineer

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    Glad to hear you had a good trip. Sounds like the Prius need to have an option to allow you to charge the battery by keeping the engine running for a few minutes when you get close to the front of a long line like that.

    If the border crossing has a 90 minute line up like that very often, just think of all the greenhouse gas being generated by the cars idoling and inching forward.

    They should have a large parking area and a rest area style park with a Take a Number System. Each car could take a number, pull into the large park area and relax at picnic tables under trees or lay out on the lawn. Some capitolists could build a shopping area as well. A large reader billboard or series of smaller ones could display the current number being served, or there could be pleasnt announcements "ready to serve 1490 to 1499". Then you could drive to a shorter line just befor or any time after you number comes up. Some capitolists could build a shopping area with a cineplex as well.
     
  3. auricchio

    auricchio Member

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    Ah, NoMo, you assume too much common sense on the part of the government. If only they would think...
     
  4. JimN

    JimN Let the games begin!

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    <div class='quotetop'>QUOTE(NoMoShocks @ May 20 2007, 02:26 PM) [snapback]446225[/snapback]</div>
    Your idea makes sense, is practical, and will benefit many people. So, no way can the government do that. However replace your idea with "duty free shop" and "casino" and enough political contributions and I'm sure it could be possible. Maybe the border crossing is on someone's sacred tribal grounds?
     
  5. daniel

    daniel Cat Lovers Against the Bomb

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    Even with the battery down to 2 bars the car should not take a minute to get up to 65. It will be a little more sluggish without the battery input.
     
  6. boulder_bum

    boulder_bum Senior Member

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    The slower acceleration would make sense. I think the gas motor gives you 70 horsepower while the electric one gives you 40. With a low battery, your electric motor may not be contributing to the 110 overall horsepower, and you may essentially have 1/3 less power.
     
  7. finman

    finman Senior Member

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    76 ponies for the gas, 67 ponies for the electric motor. combined (adding...or subtracting...losses, both mechanical and electrical) is 110 ponies. These are somewhere on John's site (john1701a.com)
     
  8. keithnteri

    keithnteri New Member

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    I have my battery down to two purple bars every day when leaving the parking garage. I have never had a problem accelerating into freeway traffic or losing power getting on the 101 here in LA. I would have your car checked. Even with one or two purple bars there is still 40% charge in the traction battery. If you lose power something is wrong.
     
  9. priusincc

    priusincc Member

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    I had same experience as Keithnteri, down to two purple bars on long mountain road with larger elevation gain. Accelerating out of turns, still had indication on MDF of electric motor boost to ICE. However, only took about 20 minutes to top then was back to full SOC in a reletively short time with all bright green bars on SOC. Didn't seem to have power loss in this time period, but don't know what would happen on extended climb. (Haven't been to sea level yet.)
     
  10. faith2walk

    faith2walk Upgraded again

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    <div class='quotetop'>QUOTE(finman @ May 21 2007, 11:09 AM) [snapback]446658[/snapback]</div>
    Your numbers are correct, but, to answer the original question, if the electric doesn't have a battery with a full SOC, then it drinks from the ICE ouput. Meaning, that some of the 76 ponies are sent to work for the elec. generator. I know that there is a drain, but not sure how much. Also, which engine gets the benefit of full power first, the ICE or the Elec?
     
  11. daveleeprius

    daveleeprius Heh heh heh you think so?

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    <div class='quotetop'>QUOTE(faith2walk @ May 21 2007, 11:17 AM) [snapback]446700[/snapback]</div>
    It was a pretty dramatic difference in the 'pull' of the car. The engine was revving quite high, and the acceleration was slow. I didn't floor it or anything, it's the beginning of the freeway and there were no cars around us. A few minutes later the battery was up to normal, and once the car was up to speed it was fine. Just took longer!

    According to the MFD, the ICE was charging the battery only, it wasn't assisting. Maybe it's because I didn't press the accelerator down far enough. Anyway, I don't believe there is anything wrong with the car.

    I did try to force the engine to stay on while in line, by shifting to neutral. Didn't work. The car just doesn't see a reason to pollute when not moving. I guess that's a good thing.

    Dave
     
  12. rachmaninoff

    rachmaninoff New Member

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    <div class='quotetop'>QUOTE(NoMoShocks @ May 20 2007, 03:26 PM) [snapback]446225[/snapback]</div>

    waiting in line for "fast food" (about 15 mins, uhg) the engine was off and the battery drained down to 2 purps. its funny this should happen for the first time the day after i see this post. well anyway i felt the engine turn on and i saw power flow from the ICE to the motor to the battery. it was the fisr time i saw this particular energy flow layout (without arrows to the wheels). so aparently this option is built right into the prius automagicaly.

    and no problems accelerating out onto the highway, have your prius checked.
     
  13. gazz

    gazz Member

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    <div class='quotetop'>QUOTE(Prius Toric @ May 22 2007, 08:06 AM) [snapback]447247[/snapback]</div>
    I had that the other morning, got to the end of the road and battery was low and the ICE stayed on at the juction and the power flowed from the ICE to the battery. Have not seen this before, scangauge shows the ICE running sometimes but the display does not show any power. Tried to reproduce it but cannont must be a low battery thing.
     
  14. morpheusx

    morpheusx Professor Chaos

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    <div class='quotetop'>QUOTE(gazz @ May 22 2007, 09:15 AM) [snapback]447250[/snapback]</div>
    Mine will do this almost every morning for up to about 30 seconds in the driveway if when I start it I dont move before it kicks on the ICE, I noticed this because before I put it in gear I check to make sure my son buckled his seatbelt. It seems to not care what the SOC is as long as the ICE is cold.
     
  15. abq sfr

    abq sfr New Member

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    Yes, mine does this too, anytime stuck for around 10 or 15 minutes (even with full charge initially) without moving, battery will go purple and provide no traction power. It does recover in a few minutes of normal driving. Just pretend you're driving a Yaris for a few minutes. Having AC running makes it worse, traction battery goes down faster and comes back up slower. Watch your heater too... if you had the climate control on 78 cooling in the afternoon and in the morning its still at the same setting you will be heating the air even if you don't know it. IMHO the climate control is the biggest weak point of the car impacting fuel economy, even though the AC is very good and efficient. Controlling it is the biggest problem for me.
     
  16. daniel

    daniel Cat Lovers Against the Bomb

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    <div class='quotetop'>QUOTE(DaveLeePrius @ May 21 2007, 09:29 AM) [snapback]446709[/snapback]</div>
    When in neutral the engine will NOT charge the battery. I don't believe there is ever a valid reason to have the car in neutral except when being towed, or being passively pulled through a car wash.

    Leave the car in Forward, or put it in Park, or even turn it off. But don't put it in Neutral.
     
  17. Zimmer36

    Zimmer36 New Member

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    it is so good to see others who have the acceleration problem too. i never looked at the battery power when it happened. I have heard of one person in my town whose car just died in the middle of the road because the engine cut out and died. He got a new car. This was a toyota salesman who told me. I have read similar things on the internet. When I have acceleration problems in the morning and in traffic jams, I sometimes get a little freaked out about everything dying.
     
  18. john1701a

    john1701a Prius Guru

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    <div class='quotetop'>QUOTE(DaveLeePrius @ May 20 2007, 01:55 PM) [snapback]446210[/snapback]</div>
    The "full" hybrid design doesn't depend on the battery-pack for electricity. In your case especially, it would be coming directly from the engine instead. So you'd have assist regardless.

    As pointed out above, it's ok to be generous with the pedal.
     
  19. richard schumacher

    richard schumacher shortbus driver

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    <div class='quotetop'>QUOTE(Zimmer @ Jul 14 2007, 09:51 PM) [snapback]478907[/snapback]</div>
    That was silly. It would have cost him a lot less to just get the Prius fixed. Probably a TSB or warranty repair.


    <div class='quotetop'>QUOTE(DaveLeePrius @ May 21 2007, 11:29 AM) [snapback]446709[/snapback]</div>
    Quite correct. If you had floored it it would have accelerated much better.
     
  20. KMO

    KMO Member

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    <div class='quotetop'>QUOTE(DaveLeePrius @ May 21 2007, 05:29 PM) [snapback]446709[/snapback]</div>
    Well, there you go. I bet you had no loss of acceleration at all, you just weren't pushing the pedal hard enough.

    The Prius will rev higher when the battery is low, and if you're using the sound of the engine to gauge pedal pressure, that means you were probably pressing the pedal less hard than usual. Ignore the noise, and just push harder if you want to accelerate faster. Pretty simple. :)

    There shouldn't be any real loss of acceleration until it's down to 1 bar.
     
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