new battery mpg less than previous?

Discussion in 'Prius v Care, Maintenance and Troubleshooting' started by James Milbourne, Jun 5, 2023.

  1. James Milbourne

    James Milbourne New Member

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    Hello Folks!
    I just had to replace my 10 year old Prius V battery. Done at the dealership, where I have serviced the car, since I purchased it. With the old battery, the average mpg was about 38.0. VERY consistent. Now with the new battery, the average mileage is jumping around LIKE CRAZY!! Showing me much lower - and much higher than you would expect. Is there some sort of "reset" necessary, or calibration? I'm perplexed!

    Thanks in advance for any input!
     
    #1 James Milbourne, Jun 5, 2023
  2. Air_Boss

    Air_Boss Senior Member

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    Replacing the battery without maintaining 12v power on the car may have reset the long-term MPG, visible on ‘DISP’, which would have been very steady. You are now building a drive by drive replacement for long-term MPG.
     
    #2 Air_Boss, Jun 5, 2023
    Tim Jones likes this.
  3. rjparker

    rjparker Tu Humilde Sirviente

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    Toggle the Display button to Average rather than Instantaneous. There are separate mpgs for Trip A and Trip B along with overall.
     
    #3 rjparker, Jun 5, 2023
  4. James Milbourne

    James Milbourne New Member

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    thanks for your speedy reply! I'm aware of the differences in settings between the "MPG (current)" and the "avg. MPG". The avg. setting had been acting almost as crazy (volatile) as the current. In the last 24 hours, it seems to have settled considerably. (only going up and down 1 to 3 miles at a time. Maybe it is self calibrating? (wishful thinking on my part! ha, ha)
    Thanks again!
     
    #4 James Milbourne, Jun 6, 2023
  5. Air_Boss

    Air_Boss Senior Member

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    As earlier noted, you are now building a drive-by-drive replacement for long-term (average) MPG, which will go up and down by the drive, until the long-term average stabilizes.
     
    #5 Air_Boss, Jun 6, 2023
  6. rjparker

    rjparker Tu Humilde Sirviente

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    The trip averages can be reset anytime. I usually reset Trip A with every fillup. It takes maybe 30 miles to settle. Realize avg mpg is built with instantaneous readings that vary from 99 to 15 mpg all the time. If the hybrid battery is low after a reset charging it takes a short time mpg hit.

    The overall odo mpg normally does not reset but your shop may have done it.
     
    #6 rjparker, Jun 6, 2023
  7. Tim Jones

    Tim Jones Senior Member

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    38 is not very good............. I always got 42/43
     
    #7 Tim Jones, Jun 7, 2023
  8. Air_Boss

    Air_Boss Senior Member

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    In my recent experience, a dead-dead 12V aux battery resets LT AVG MPG (but not ODO) and anything connected to the OBD2 port.
     
    #8 Air_Boss, Jun 7, 2023
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