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Timer function needs improvement

Discussion in 'Gen 1 Prius Plug-in 2012-2015' started by fberger, Apr 13, 2012.

  1. fberger

    fberger Junior Member

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    With a limited capacity such as on the Pip, many owners will recharge more than twice a day. I for one am recharging 3 to 4 times per day. Given that Toyota recommends to let the battery rest after use and schedule charging to end just before using the car again, I constantly need to manually adjust the charge start or stop time to protect the battery.

    I need Toyota to add a simple function to the timer that is not based on a specific hour, but rather based on a time delay. Toyota should make a recommendation to let the battery rest at least a certain amount of time after use, and that amount could be instantly selected. If the time is based on previous discharge rate, or current temperature of the battery, then Toyota could even calculate a recommended value that can then be overridden based on personal schedule needs.

    Whenever I use the timer function, I could hit the timer button and toggle between start time, end time and delay. Then, engage the timer and I would know that charging would start at a time that is healthy for the battery.
    This added functionality would not cost Toyota any more and make my life easier every time I need to charge.
     
    #1 fberger, Apr 13, 2012
    1 person likes this.
  2. ukr2

    ukr2 Senior Member

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    You should add this to http://priuschat.com/forums/toyota-prius-plug-in/105508-wish-list-pip.html
     
    #2 ukr2, Apr 14, 2012
  3. ryogajyc

    ryogajyc Active Member

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    Where does Toyota recommend this? I think the two relevant points from the Owner's Manual pg. 93 are:
    I believe the first point applies to leaving the car undriven for a few days. The second indicates the car should be charged just before driving, not not charged after driving.
     
    #3 ryogajyc, Apr 15, 2012
    1 person likes this.
  4. fberger

    fberger Junior Member

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    Re-reading that part of the manual, I think you are absolutely right. We only need to worry about not leaving the battery fully charged for too long, instead of letting it rest before recharging it. I think I got that advice somewhere here on PC, but if we follow the manual then that is not necessary.
    From now on, I will time my recharging based on when I plan on driving.
     
    #4 fberger, Apr 15, 2012
  5. Allannde

    Allannde Just a Senior

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    I think the last point is because if a fully charged car is left to sit, the charge "leaks out" and you have less charge when you go to drive. Charging just before you drive means you have more charge. It is only an issue of battery preservation if the car sits for long periods of time without use.

    If the drive just before you stop is short or gentle, battery temperature should not be an issue. I check my traction battery temperature and never see an alarmingly high temperature. If I expect more drives during the day, I charge right away.
     
    #5 Allannde, Apr 15, 2012
  6. jim335

    jim335 Member

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    It is not that the charge will leak out, it is that it is not good for li-on batteries to sit fully charged for long periods of time. nimh batteries will discharge much more quickly than li-on batteries.
     
    #6 jim335, Apr 20, 2012
  7. CharlesH

    CharlesH CA HOV Decal #5 on former PiP

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    And just to complete the picture, lead-acid batteries should be stored fully charged.
     
    #7 CharlesH, Apr 20, 2012
  8. Biking Maniac

    Biking Maniac Five Prius – have not sold one yet!

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    I have a question about the timer function. I set the timer to be done by 7 am. The car seems to start charging right before 4 am regardless of the state of charge. Two nights this week, at 2-3 miles of EV remaining, the charge finished by 6 am. Last night we had 8 miles of EV remaining and the charger was on from 4-5:30 am. Has anyone found that the charger planned ahead based on remaining charge, or does it really just start charging three hours ahead of the "ending" time?
     
    #8 Biking Maniac, Apr 20, 2012
  9. rogerv

    rogerv Senior Member

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    I have just noticed that mine behaves in a similar fashion. I have the "finish" time set, and the charger starts exactly three hours ahead of that time, regardless of the number of EV miles remaining. Even when it is down to nothing, the charging finishes in just under two and a half hours.
     
    #9 rogerv, Apr 20, 2012
  10. Rebound

    Rebound Senior Member

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    Your only solution will to buy a smarter charger. They're bound to hit the market sooner or later.
     
    #10 Rebound, Apr 20, 2012
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