1. Attachments are working again! Check out this thread for more details and to report any other bugs.

When should I replace the hybrid battery?

Discussion in 'Gen 2 Prius Main Forum' started by Dummy, Sep 7, 2024.

  1. Dummy

    Dummy Member

    Joined:
    Mar 24, 2019
    108
    22
    2
    Location:
    Colorado
    Vehicle:
    2005 Prius
    Model:
    II
    I’ve got a 2005 with 250k miles still running the factory battery. It gets 42 mpg on the dash readout and I’ve read on here that it should be bumping 50. My math tells me that the extra 5 mpg won’t be enough to justify the cost. Today I started wondering if the slightly weak hybrid battery is putting more stress on the engine. What all should I consider when deciding to replace it or not?
     
    #1 Dummy, Sep 7, 2024
  2. mr_guy_mann

    mr_guy_mann Senior Member

    Joined:
    Sep 3, 2020
    3,668
    1,715
    0
    Location:
    NJ-USA
    Vehicle:
    2006 Prius
    Model:
    Four
    Really, the only consideration I have is if (when) the battery starts "acting up".

    Dashboard warning lights, rapid increase & decrease on the battery gauge, big drop in mpg (by 10-15 MPG or more), engine "revving much higher".

    All of these are common symptoms when the hybrid battery is failing.

    Posted via the PriusChat mobile app.
     
    #2 mr_guy_mann, Sep 7, 2024
    Brian1954, dolj, Dummy and 1 other person like this.
  3. Dummy

    Dummy Member

    Joined:
    Mar 24, 2019
    108
    22
    2
    Location:
    Colorado
    Vehicle:
    2005 Prius
    Model:
    II
    I’ve got none of those symptoms, just the slightly lower fuel economy. Occasionally I’ll have a tank that averages 39 mpg (about every 4th or 5th tank).
     
    #3 Dummy, Sep 8, 2024
(You must log in or sign up to post here.)