Low usage contributing to part failures? (2009 Prius)

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by JCooper, Sep 29, 2019.

  1. JCooper

    JCooper New Member

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    Hello.

    Can low usage contribute to electric part failures?

    I have a Gen 2 2009 Prius.
    For about a year now, I have worked from my apt., so I rarely use it.
    I am driving an average total of nine (9) hours, 250 miles per month. Broken down, it's a half-hour weekly trip, and 2 long trips at the end of the month. Car is at 60,000 miles.

    I am getting a lot of electrical part failures recently, seemingly every 1-2 months. My battery computer assembly (part no. 89890-47092), electric inverter water pump (04000-32528), my brake actuator assembly, and now some battery cells have all failed and needed replacement. Admittedly two of the items mentioned have enhanced warranties or recalls, (and it's probably about time battery cells start failing), but I had had zero issues with the car in the 9 years prior to this, and all of these have occurred in the span of half a year.

    So my question is the following: Is a Prius ill-suited for such a sedentary lifestyle, or are these problems just natural for my car's age?
    Even if the latter, are these extended periods -sometimes about a week long- of idleness contributing to these part failures?

    I'd like to be able to take an informed decision on whether I should ride it out, or if it's time to move on, and/or if I'm actively contributing to my own misery.

    Thank you for any insight.
     
    #1 JCooper, Sep 29, 2019
  2. bisco

    bisco cookie crumbler

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    welcome!

    have you owned it since new?

    as you said, two of the failures are unrelated to usage.

    the battery ecu is unusual, and the only relationship might be corrosion, but that isn't related to usage i don't think.
    the hybrid battery, now you're talking. a new one is $1,600. and will get you another 10 years, but you're not saving anything with that kind of mileage over a straight gasser.

    i'm surprised you aren't having 12v problems.
     
    #2 bisco, Oct 2, 2019
  3. pasadena_commut

    pasadena_commut Senior Member

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    Sitting like that isn't going to be good for either battery. The cells in the HV battery will all have slightly different discharge rates. If the car is being used it will be, or at least should be, doing things to keep everything balanced, but if it sits for a week that will let them drift apart. (Civic Hybrids have a warning in the user manual saying the car must be driven frequently to avoid this.) If there is enough parasitic load the 12V might be discharged quite a bit. That one you can test even without a voltmeter. Without touching the brake press the power button once and then pull up the diagnostics in the MFD. (I don't recall the magic incantation off hand, but you can find it in this forum.) That will show the 12V battery voltage without starting the inverter which would bump it back up again.

    I can sort of see why the inverter pump might have gone too. When pumps like that are on their way out they often become harder to start, but will run once started. If it sits long enough the parts might bind together enough that they don't start, and then the overheat condition applies the coup de grace. However, this would not kill a healthy pump, just put a sick one out of business a little earlier.

    The brake actuator failure is probably just a coincidence.
     
    #3 pasadena_commut, Oct 2, 2019
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