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Sitting in Park with A/C on - Is Pack Drain Normal ?

Discussion in 'Gen 2 Prius Main Forum' started by sas0611, Jun 5, 2008.

  1. sas0611

    sas0611 Member

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    Today I was eating my lunch in the car with the A/C in auto mode and in Park. The car was in 'ready state' (not accessory mode). I made sure that the car was powered on because I recall reading somewhere in the manual that it should be if running A/C at a standstill for any length of time.

    After about 20 minutes I was ready to take off. I put the car in drive and I noticed every time I pressed the accelerator the ICE was coming on. Since I was in a flat parking lot I was surprised that I wasn't starting out in electric mode. I'd never had the ICE coming on with every depression of the accelerator at sub 5 miles per hour..

    I switch to INFO mode on my MFD and saw that the pack had been nearly fully depleted (1 purple line was left). It may have been depleted completely since I didn't look at it until a few accelerations after idling.

    I immediately took it out on the road and did a series of manuevers to recharge pack. This experience has me asking the following questions of the more senior members or those who aren't newbs like me.. Thanks in advance for your responses.

    1. Why didn't the ICE come on intermittently while I was eating my lunch to replenish the pack before it hit this seemingly fully drained condition.

    2. Would the ICE have eventually come on had I sat there longer drawing power for the A/C from the pack or would it then move on to deplete the 12 Volt standard battery after depleting the pack.

    3. Is this similar to a run out of gas condition which damages the hybrid system. I'm guessing an out of gas situation continues to pull from the pack until the pack no longer can provide and energy and thereby damages it. Is damage to the hybrid system possible in this way ?

    4. Is there something wrong with my prius or is this a design flaw in all of them or is this functioning as designed.
     
  2. Maytrix

    Maytrix Member

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    The ICE would have come on to charge the battery if it had dropped much lower - you were probably on the threshold. The ICE turning on at every press of the gas pedal was normal too as it will do that when its very low.

    I have done the same thing and noticed the ICE would come up around 2 bars. It would run for 2 minutes or so and then shut off. Then would repeat after awhile.

    Why would you bother doing anything to try to charge it? Just drive it - The car will take care of itself. I have seen mine down to 1 bar, but never lower than that. If it wasn't showing any bars, there might be reason for concern.
     
  3. prius729

    prius729 New Member

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    I did the same thing today, sat in the car in park and at exactly 2 bars remaining the ICE came on to recharge.
    Next time leave it in INFO mode and witness it yourself.
     
  4. Maytrix

    Maytrix Member

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    What I found most interesting is that the timing was consistent. The time between it turning on and the time it remained on. I suspect this would be different each time depending on other factors such as outside temp, whether the car is in the sun or shade..etc, but it definetely had a pattern.
     
  5. john1701a

    john1701a Prius Guru

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    Everything was working completely normal. There was no need to intervene. Nothing was actually required of you.

    The system was taking advantage of recharging opputunities, rather than running when the power of an engine was overkill. The battery-pack was still above 40% capacity. Lower than that simply isn't shown, since displaying it serves no purpose. The system doesn't allow discharge below that.

    Next time, just drive it.

    .
     
  6. morpheusx

    morpheusx Professor Chaos

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    This is normal. I look at this as being another advantage of having a Prius. You were able to sit there in the hot parking lot and enjoying the air conditioner with the engine just coming on for a few minutes at a time to maintain your battery. You can do the same thing in the winter sit in the parking lot with the heat on and the engine will cycle on for about 2 or 3 minutes then shut off for about 5 - 10 minutes depending how cold it is to keep the heat going.
     
  7. richard schumacher

    richard schumacher shortbus driver

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    Completely normal. When sitting as you were the battery level will bounce between 2 and 3 or 4 bars. When you launched it was at 2 bars and got depleted to 1 bar because of the immediate energy demand of driving, and the engine needed to run a lot to make it up.
     
  8. abq sfr

    abq sfr New Member

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    Yup... Wendy's drive-up here is sooooooo slowwwww, I can have a full battery... less than 15 minutes later I'm down to 40% with ice coming on, and I still don't have my burger :mad: and when I get it the order's wrong 80% of the time. I digress. Don't be afraid to turn your AC up to 80 degrees or more, I'm more comfortable with it on 80 than 72 if outside its 94, give it a try. Running the battery down to 40% is one of those things you get used to eventually.
     
  9. alanh

    alanh Active Member

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    1. You were probably on the verge of it coming on. I've sat parked in 100F+ weather and it does cycle on and off.
    2. Yes, the ICE will come on to charge the hybrid battery if it gets too low. The A/C runs off the hybrid battery only; it cannot drain the 12v battery.
    3. No. The hybrid system will not allow the battery to get too low. Even at zero bars, the battery still has about 40% charge left. The Prius will run the ICE to charge it as necessary.
    4. No, it's working as designed. Just relax.
     
  10. jayman

    jayman Senior Member

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    Completely normal, there was no need to "make" it charge

    The Prius A/C is far more efficient than regular belt-driven automotive A/C. It's variable speed and will run at just the speed needed to maintain cabin temp
     
  11. Gilbert

    Gilbert Member

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    some time ago i tinted the car windows front and back, the next day i went to get some lunch and refuel, i was stuck on the drive thru for a while and the battery went down to 1 line, and i had to turn the ac off, and cook myself inside because i didnt want the battery to run out and could not roll the windows down because of the tints... and i was also on my last blinking bar of fuel. i also turn the ac off when im in traffic to void running the battery to the purple lines.
     
  12. richard schumacher

    richard schumacher shortbus driver

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    There is no need to shut off the AC to avoid running down the battery. The car manages its own battery and will start the engine whenever needed to recharge it.

    Shutting off the AC on a hot day might in fact reduce MPGs, because the battery system gets its cooling air from the cabin. If the battery system gets too hot it can throttle itself and charge and discharge less than it should. Leave the AC on and don't worry about it.
     
  13. ZC1

    ZC1 Junior Prius Owner

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    Easy answer. Despite the need to recharge the battery, the preprogrammed car needs to keep the catalytic converter hot enough for pollution purposes. This is why, in the future, you won't be surprised that you are not starting out in electric mode.

    The pack doesn't allow itself to get depleted, your assumption is the MFD is showing you the 0%-100% charge of the battery. It actually shows 40% to 80%.

    You should of heard it from others here, that is completely unnecessary.

    My guess is in 5 minutes the ICE would have come on, possibly sooner. The bar level gauge is not very accurate opposed rather to a digital readout. This happens to me all the time, one purple bar when not actually driving, then eventually the ICE starts up.

    The ICE would have come on, unless you had a very very specific kind of ECU failure the batteries would charge as necessary.

    NO, it is not similar to an out of gas condition.

    Nothing is wrong with your Prius, it's functioning normally as one would expect.

    ZC1
     
  14. ZC1

    ZC1 Junior Prius Owner

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    It's your car so you can do as you wish. Running to the purple lines is NORMAL and expected in design.
    This is like saying " I shut the engine down in traffic cause I want to avoid running the gasoline to the low levels. Except in this case, the Toyota recharges itself.

    ZC1
     
  15. jayman

    jayman Senior Member

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    As others have stated, this will cause the NiMH battery pack to run abnormally hot. There is a cooling fan for the pack, but once the pack heat-soaks your fuel economy will drop.

    The NiMH battery pack is most efficient, and will last longest, at normal room temps
     
  16. sas0611

    sas0611 Member

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    Thank you all for your replies - it seems that my concern was founded in not knowing that a 40% reserve was maintained even when MFD reports 1 bar remaining on charge. Also, had I given it another minute or two, I'd probably have forced the ICE to come on. Your posts filled some of the many holes I have in my understanding of how the prius negotiates the seemingly unlimited combination of conditions it can encounter. The more I drive it the more I realize that the car is a brilliant piece of technology and engineering. It is all so seamless and smooth. It seems as though it is an entity of sorts - self monitoring, self correcting, anticipatory capabilities, concerned with self preservation even when it lands in the hands of clueless new drivers. I am already looking for decals for my super white which is at some point going to arrive. Something like ' rotate the pod HAL' would be appropriate (from Kubricks 2001 space odyssey.
     
  17. jayman

    jayman Senior Member

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    Personally, I would go for stickers "Open the pod bay doors Hal"

    As long as the Prius doesn't respond

    "I'm sorry Dave, I can't do that"
     
  18. aminorjourney

    aminorjourney Mum to two prius!

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    I have always thought that it would be nice to utilize some of the features of certain electric vehicles out there, and have the AC come on a few minutes in the morning before you get in so that you're not getting into a boiling hot car.

    Perhaps some hack, where you can text your car and get it cooled down before you drive off...

    Oh the possibilities are endless ;)

    (I'm being a bit silly here, and of course, I'd never advocate wasting energy in such a way ;) )
     
  19. lenjack

    lenjack Active Member

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    You figured it out. 1 purple bar is not nearly depleted...it's 40% charged at which point the ICE will kick in. The car will not allow the battery to fall below 40% charge.