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Parked with Accelerator

Discussion in 'Gen 3 Prius Main Forum' started by eglmainz, Sep 21, 2009.

  1. eglmainz

    eglmainz New Member

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    I had noticed somewhere on this 2010 forum, a mention that when you are in 'park' with the Prius, but in "Ready' mode, if you press the accelerator, the ICE will come on. This can be useful for having someone diagnose an issue on the ICE, but I am curious to know if it will also charge the engine during that period.

    I think it does not, because of the following: When I am parked somewhere for a while, in Ready mode, I notice that when the battery drops to two 'pips', the ICE will come on for about 2-3 minutes, during which time the battery will gain one to two 'pips, making for 3 to 4 before the ICE shuts off. However, if I wait till the two 'pips' on the battery indicator are there, and then I press the accelerator pedal, which in turn, activates the ICE, even after 3-5 minutes of it running, the battery level still has only two 'pips', and the ICE starts up soon afterwards to recharge everything.

    Does anyone know for certain (maybe who has read the technical documents) whether this will cause the ICE to recharge the battery, or is it designed to bypass this in these cases?

    While the second question seems pretty different, I think the question is very similar. Other time, when driving, I sometimes place my car into "N" , allowing for a longhill downhill coast, without requiring my feathering the pedals to keep it in the 'stealth' mode. The second question is when in 'Neutral', if I apply the brakes slightly, I see that the 'Hybrid System Indicator' does not reflect any energy being sent to the battery, but I have to assume, since some braking is still taking place, and is likely not the friction brakes, does this generated energy still go to the battery, and is just not displayed on the screen, or is 'wasted', and not captured at all?
     
  2. Blind Guy

    Blind Guy New Member

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    * The manual states that in "N", NO electrical power is captured.

    David (aka Blind Guy)
     
  3. eglmainz

    eglmainz New Member

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    David,

    Thanks for the response. The reason for my asking is that while I saw that as well, I also noticed that when using the brakes in that sort of situation, it is all regen braking. Additionally, this weekend while going down a 2 mile grade, I saw that although I placed in neutral at the top of the hill, with only 4 bars in the battery meter, at the end of the grade, as I went back into the 'D' mode, the battery meter was now showing 6 bars, although a second after the ICE jumped back to life, I only had 5 bars again.

    So while I agree that the manual does indicate that the 'no electirical energy is captured', it would seem as though some may be getting captured, even if only inadvertently.
     
  4. Manksgloob

    Manksgloob Member

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    On the Gen II, hitting the brakes while shifted into neutral used the mechanical brakes rather than the regenerative ones.

    It was a great way to clean off rust from the rotors. =D

    Perhaps someone else has an explanation as to why your battery meter went up.
     
  5. a priori

    a priori Canonus Curiosus

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    The Owner's Manual, page 30, provides the clear answer David noted above:
    Charging the battery

    l As the gasoline engine or regenerative brake charges the hybrid battery (traction battery), the battery does not need to be charged from an outside source. However, if the vehicle is left parked for a long time the hybrid battery will slowly discharge. For this reason, be sure to drive the vehicle at least once every several months for at least 30 minutes or 10 miles (16 km). If the hybrid battery becomes fully discharged and you are unable to jump-start the vehicle with the 12 volt battery, contact your Toyota dealer.

    l If the shift lever is in “Nâ€, the hybrid battery (traction battery) will not be charged. When driving in heavy traffic, operate the vehicle with the shift lever in “D†or “B†to avoid discharging the battery.
    I know you've acknowledged this and simply are wondering why the SOC display varied so much. My best guess is that the SOC displays based on demand and anticipated use. If there is very heavy draw, the display is likely to drop very quickly, to advise you of the usage. It could be that once you stopped drawing (by taking it out of drive), the SOC display jumped up to reflect the "current" draw. It also likely dropped quickly for similar reasons.

    Perhaps we have an EE or someone really familiar with these gauges who can give a proper response.
     
  6. eglmainz

    eglmainz New Member

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    Thanks. I did not doubt David, his answers are often very concise and accurate. It was simply re-iterated to ensure that this information source (the manual) was not wrong (as it was with 88 Octane Gas, or the Valet Key, etc.).

    Since my observation in real-world was different, I thought I would ask. It does make sense that the SOC indicator would be off. I know that I have seen similar issues with other SOC indicators in everything from my iPhone, to my Laptop, so I suppose it would be possible on the Prius too.
     
  7. a64pilot

    a64pilot Active Member

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    I think the SOC is merely a volt meter. I think any battery under load will show a voltage drop that may not be in line with it's actual charge state, and a battery under no load will display a voltage that may seem to indicate a higher than it should SOC.
    I think any display on the Prius is intended for informational purposes only, they aren't meant to be real accurate and errors are there.