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Consistently low mpg - Battery issue?

Discussion in 'Prius v Care, Maintenance and Troubleshooting' started by caedward, Aug 21, 2017.

  1. Beachbummm

    Beachbummm Senior Member

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    im in florida and with the heat I find the batteries to have issues northern states don't have.. under 35 mpg on a prius is a joke ..I get worried when I see under 42mpg and I have an 08.. I think you are on the right track with a weak battery but if its under warranty id call Toyota customer service and let them authorize a replacement. its not going to get better as it ages.
     
  2. DanMan32

    DanMan32 Senior Member

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    A weak 12v battery shouldn't matter much. The inverter provides all of the 12v power once it is in Ready or Ig-on.
    A weak traction battery is another matter.

    Posted via the PriusChat mobile app.
     
  3. bisco

    bisco cookie crumbler

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    your battery is close to dead. and when it is weak, needs to be constantly recharged by the hybrid battery which needs to be recharged by the ice running more.

    many reports here of people replacing a weak battery and seeing increase in mpg's.
    replace yours before you get stranded somewhere.(y)
     
  4. mikefocke

    mikefocke Prius v Three 2012, Avalon 2011

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    Beachbummm

    Comparing the MPG of a lighter hatchback Prius to the MPG from a station wagon shaped, heavier, differently geared v is apples and oranges and not very helpful to the determination of what may be different about the OP's experience with his v.
     
  5. AMP

    AMP April 2012

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    You could be right about the traction battery.
    I am no expert, so I am just throwing this out. Those numbers are close to cold weather numbers, or the ICE is not warming up. Is it possible the coolant thermostat is stuck open. It wouldn't matter on a long trip, where you are getting good miles, but on short trips, the engine never quite warms up, so the car doesn't kick into electric drive.

    Just a thought.....
     
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  6. Robbomac

    Robbomac Junior Member

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    Here are a couple of shots of my dashboard on a routine trip - outside temperature was 88F. The first picture is immediately after powering on the car - notice the battery at 2 pips and the ICE is on.

    3 minutes later, I am leaving my building's garage. The battery shows 3 pips and the car is in EV mode.

    In typical city driving, I rarely see the battery at more than 5 of 8 pips. Also notice, my tank mpg of 36. This is the same tank where my wife logged 48 mpg on a mostly-highway excursion in the first 80 miles.

    IMG_2659.jpg IMG_2660.jpg
     
  7. Beachbummm

    Beachbummm Senior Member

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    was the AC on when she logged 48mpg?
    that's the biggest draw on the battery but it still should not drop that much with it on..
    think a trip to the dealer for testing would be in order, might get a free replacement battery
     
  8. bisco

    bisco cookie crumbler

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    great pics, it's definitely your commute, no worries.(y)
     
  9. Robbomac

    Robbomac Junior Member

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    I had my Prius v serviced yesterday, and asked to have the traction battery checked. The service advisor said the battery was OK, and only gave me this one page report for the tests that were done. I had hoped for something more detailed. Should I be content with this?

    Scanbot Sep 11, 2017.jpg
     
    #29 Robbomac, Sep 12, 2017
    Last edited: Sep 12, 2017
  10. mikefocke

    mikefocke Prius v Three 2012, Avalon 2011

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    Did you ask what the first line meant. Update = yes. Did they or did the test indicate it needed to be done? Any recalls done?
     
  11. Robbomac

    Robbomac Junior Member

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    They said nothing about this sheet when I picked up the car except to say that the battery tested OK. I was hoping someone here might be able to fill me in on what the service advisors at Servco Toyota didn't tell me!
     
  12. bisco

    bisco cookie crumbler

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    how much did they charge you for the battery health check?
     
  13. Robbomac

    Robbomac Junior Member

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    Fortunately, nothing. But I got pretty much what I paid for...
     
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  14. bisco

    bisco cookie crumbler

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    maybe they don't know how to do battery health test. otoh, it wouldn't be worth paying for one, since the computers monitor the battery voltage parameters, and report with a trouble light when they go awol.
     
  15. lrisius

    lrisius Member

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    I had a thought for a test that you could do. I've noticed with our v that mileage is not great for the warm up period but once it is warmed up, the mileage is very good. Our 2015 Level 3 v displays the mpg since the last re-start. Could you do a test where you drive the car for 15 minutes or so (enough to get it warmed up good) and then turn it off and restart so your mpg indicator resets and see what the mileage is then? That would tell a lot about how your hybrid system is functioning and whether something is really wrong.
     
  16. DanMan32

    DanMan32 Senior Member

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    It is normal for the battery to be around 2-3 when left idle (not moving) for long periods. It will only start charging to a higher level when you are driving.

    I tend to agree, it seems your trips are so short, you never come out of warm up.

    Posted via the PriusChat mobile app.