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Battery SOC on speed control vs foot pedal.

Discussion in 'Toyota Hybrids and EVs' started by CamryDriver, Jul 17, 2018.

  1. CamryDriver

    CamryDriver Active Member

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    The battery seems to stay at 3/4 to 7/8 full while using the foot pedal to regulate the speed of the car. The actual SOC might go higher or lower but the car seems to "like" the battery to be mostly full.

    The situation is completely different on cruise. The battery will drop to about half charged and stay there while on cruise.

    Has anybody else noticed this type of behavior? How about with other Toyota hybrids?
     
    #1 CamryDriver, Jul 17, 2018
  2. Anthony Poli

    Anthony Poli Junior Member

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    If the soc is always at 3/4, maybe your foot is too heavy. From my own experience the cruise control will use ev, but manually I can use ev and make it last longer than on cruise control.
     
    #2 Anthony Poli, Aug 16, 2018
    Last edited by a moderator: Aug 16, 2018
    LasVegasaurusRex likes this.
  3. LasVegasaurusRex

    LasVegasaurusRex Active Member

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    the cruise control is not very intelligent and can eat away as much as 5mpg
     
    #3 LasVegasaurusRex, Aug 23, 2018
  4. CamryDriver

    CamryDriver Active Member

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    Ahh, yes you could purposely use EV mode to deplete the battery but they say that isn't a good idea.

    I've heard a couple of reasons for avoiding excessive EV use. The first is that the less you use the battery the longer it should last. Deep cycling a battery is hard on a battery or so they say. I'm sure this does not apply to certain battery chemistries that develop "memory".

    The second reason is that charging and discharging a battery is said to be inefficient. It is strange but evidently true that for a hybrid to get the best mileage one must avoid using the battery as much as possible. Of course you use it some but excessive use is said to be less efficient.
     
    #4 CamryDriver, Aug 24, 2018
  5. Trollbait

    Trollbait It's a D&D thing

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    The secret to how hybrids get great fuel efficiency is in the engine. The electric side helps the engine efficiency by letting it shut down or give it a boost during the time the engine would be burning fuel under less efficient conditions.

    The gen2 Prius had a smaller displacement engine than the base one in the US Corolla, that was also trading off power for efficiency through the Atkinson cycle. Just using that engine alone would yield better fuel economy over the Corolla, but the performance would be intolerable for most. The electric motor and battery restore the performance, and allow efficiency increasing techniques like regenerative braking and turning the engine off while coasting and at stops to more than make up for the loses of adding them.

    As for manually using EV in hybrid, the main reason we warn people about using it is that it is quite easy to reduce your overall efficiency by over using it. When the SOC is low, the system wants to charge it back up. Dropping it low regularly means will result in having the engine running inefficiently at some time in order to charge the battery.
     
    #5 Trollbait, Aug 24, 2018
  6. Anthony Poli

    Anthony Poli Junior Member

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    Making the EV last longer, in terms of the maximum range quoted in the manual v driving efficiently on EV.

    My manual states 0.5 miles, which I have managed to stretch that to 5 miles. Making the most of regenerative braking and keeping momentum, using the engine to accelerate to your desired speed, then letting the car switch back to EV.

    The way Toyota limits the use of the batteries, extending the life of the batteries. So you do not have to worry about using EV.

    EV and EV mode are different.



    iPhone ?
     
    #6 Anthony Poli, Aug 25, 2018
  7. CamryDriver

    CamryDriver Active Member

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    I understood that you were doing that, I suspect by keeping the torque meter under the critical spot just above the word ECO. What I'm saying is that the way you are driving is less efficient as a result of your increased electric only time. We don't plug in our cars so the energy to drive 5 miles on electric comes from the gas engine. They say, and I believe that it is more efficient to use engine power directly than it is to add the additional inefficiency of charging and discharging the battery.

    This is different than recovering energy that would be lost to friction braking which is "free" energy that would otherwise be lost on a non-hybrid.
     
    #7 CamryDriver, Aug 25, 2018
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  8. Trollbait

    Trollbait It's a D&D thing

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    Run the SOC down with EV mode, and don't recharge it right away with regen, then the engine comes on and will run harder to charge the battery. This can mean a reduction in overall efficiency because replenishing the battery invokes conversion losses.

    The half mile range quoted in the manual is for EV mode, and this mode intended purpose is mainly for when you need to shuffle parking spots or pull the car out to get to the lawnmower; times when there really isn't a trip to keep the engine off.

    Managing to keep the ICE off for extended distances it different; it likely won't drain the SOC as far as EV mode will. In the past, this was referred to as gliding or coasting.
     
    #8 Trollbait, Aug 25, 2018
  9. Anthony Poli

    Anthony Poli Junior Member

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    You said what I was thinking and made a better job of writing it.





    iPad ?
     
    #9 Anthony Poli, Aug 26, 2018
  10. CamryDriver

    CamryDriver Active Member

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    Based on this quote I had the impression you were using the battery beyond what occurs in a glide.

    A glide might display "EV" on the dash but as I understand it a glide attempts to neither charge or discharge the battery. A glide is like being in neutral. Glides are said to be very efficient. Using the battery beyond what would normally be captured by regen less so.

    Battery University claims that charging a lithium battery is much more efficient due to the lower internal resistance of a lithium battery. If this is true then the conventional wisdom might not apply to hybrids sporting lithium batteries...
     
    #10 CamryDriver, Aug 26, 2018
  11. Trollbait

    Trollbait It's a D&D thing

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    The wisdom still applies. It just means Li-ion doesn't lose as much as NiMH to the conversion losses.
     
    #11 Trollbait, Aug 27, 2018
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