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25 MPG, New Yellow Top, Dr. Prius 50% Life Expectancy

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by goodjobkale, Aug 8, 2024 at 11:30 AM.

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  1. goodjobkale

    goodjobkale Junior Member

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    2009 Prius.

    Title says most of it. I've been driving the car a lot more % of the time now that my wife has a job she can public transit (or bike) to. And I've been suspicious of the proclaimed MPG for a while now (I know they're not terribly accurate). It's been dropping from 46-ish when we bought the car in 2016 to 39-ish now.

    At some point in the past8 years, I did calculate the mpgs and it was close enough that I didn't sweat it.

    However, recent calculations put my mpg at about 25. That's mostly city miles, with many very short trips (<2 miles to the grocery store). New yellow top battery with less than 500 miles on it. Recent vacation trip (lots of highway miles) read as high as 50 on the display (higher than I ever recall before) and, if I recall correctly (boy, I wish I wrote it down) was acceptable when manually calculated (40+ mpg).

    So my current working assumption is that highway miles are ok and city miles are terrible.

    I pulled out the Dr. Prius app and battery life expectancy was stated at 50%. Battery health check didn't show any errors, although I can't run the "accelerate hard, brake hard" where I live (will do it this weekend when I visit family in the 'burbs).

    So... how trustworthy is Dr. Prius life expectancy? 50% is also edging up against Dr. Prius's "poor" life expectancy rating. And, lastly, is this the expected behavior with a failing HV battery (low city, ok high MPG).

    Thanks!
     
    #1 goodjobkale, Aug 8, 2024 at 11:30 AM
    Last edited: Aug 8, 2024 at 11:43 AM
  2. bisco

    bisco cookie crumbler

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    how many miles on her?

    'many short trips' is a big mpg killer

    dr hybrid life expectency isn't that accurate, but i don't think anyone has quantified it.

    the battery is used more around down, so it would likely have a larger effect on mpg's vs highway.

    get a free load test on the 12v at many auto parts stores, don't just trust the age.

    many other parts and systems in your car could be affecting mileage, proper maintenance is crucial.

    lastly, extreme heat and cold are mpg killer's, what is it like in the milky way?
     
    #2 bisco, Aug 8, 2024 at 2:03 PM
  3. TMR-JWAP

    TMR-JWAP Senior Member

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    Those many 2 mile trips are the mpg killer. The first 5 minutes of 'on' time are basically a warmup stage for the car. I've had a handful of Gen 2s and they pretty much all land around 25-28mpg during that first 5 minute block. If you rarely do 20-30 minute steady drives, the car never gets the opportunity to experience the 55+ mpg blocks to raise that average. I wouldn't consider it to an abnormal situation that requires any repairs or anything.
     
    #3 TMR-JWAP, Aug 8, 2024 at 2:59 PM
  4. PriusCamper

    PriusCamper Senior Member

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    I'm not a fan of the life expectancy test... There's too many variables to be accurate. But it does give you a general sense of how your pack is doing.

    My advice is to learn all you can about hybrid battery reconditioning which will bring your pack back up to 96% capacity and if done every 18 months you'll significantly extend the lifespan of the pack. Learn more here: FAQ - Hybrid Automotive

    Also, if you're on a budget, or just want to save money you can build your own equipment to do this: Build Hybrid Battery Maintenance Gear For Under $100 | PriusChat
     
    #4 PriusCamper, Aug 8, 2024 at 3:08 PM
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