Signs/hints that your hybrid battery was on its last legs

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by rubia, Dec 28, 2025.

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  1. indel

    indel Member

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    I reported her several days back and I expect after the latest outburst, she will be removed. Until then, I too, will use my ignore function.
     
    #61 indel, Dec 31, 2025
  2. rjparker

    rjparker Tu Humilde Sirviente

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    One thing for sure is an old Prius needed as a lifeline in a rural area is a concern if you are on a very limited budget and perhaps very little credit.

    A battery or head gasket fail could cause a crisis but the reality is its really not possible to predict one of the big ticket items much less prevent something like the battery, head gasket or brake booster problems. There are theories like changing fluids twice as often and there are lower cost stopgap solutions for batteries and head gaskets once they happen.

    Most of us can afford a better primary car while keeping a gen3 as a local commuter vehicle, or are strong diy with good knowledge or we have enough cash or credit to bail out the car quickly.

    The only real way to improve gen3 reliability is to replace the car with a much newer model.

    If someone has very limited resources and find themselves worrying about what might happen even though its ok now, these cars are really a poor fit. If I found myself in that situation I would set a short term goal to change the car or improve my resources.
     
    #62 rjparker, Dec 31, 2025
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  3. rubia

    rubia Junior Member

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    Thanks for this, Happy new year to you, too.
     
    #63 rubia, Dec 31, 2025
  4. Tideland Prius

    Tideland Prius Moderator of the North
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    Imma need some time to sort through this battlefield. What the heck guys? Can't a brother go away for vacation?
     
    #64 Tideland Prius, Jan 15, 2026
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  5. Tideland Prius

    Tideland Prius Moderator of the North
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    Ok yeah as an outsider reading this, there definitely was some confusion. I only saw one reasonable reply to her initial question on the first page and it seems like once someone misunderstood the question, the rest of the replies followed that misunderstanding. There was talk of Li-Ion battery and battery reconditioning or extending the life. The initial question was simply "how did you know the battery was on its last leg". Not "how to repair", not "how to replace", not "how to extend its life".

    Anyway, FWIW, while I wasn't there for the the last part of the Gen 2's life, I have had questions asked by a family member who was daily driving the Gen 2 and from what I remembered, the two obvious things that occurred before battery failure was

    1. Increased mpg. It was getting 6L/100km instead of the usual 4.7-5.0L/100km in city driving
    2. The battery meter fluctuated more often. The SOC would go from 6 or 7 bars down to 2 bars and back up as the engine recharged much more rapidly than normal. I suppose the engine recharging the battery contributed to point number 1 about increased mpg (in addition to having almost no help from the battery anyway).

    I don't know how long that lasted but I'd wager a few months in advanced. It failed over the winter time. We were still able to hobble the car to the dealer (it didn't outright die. It was still exhibiting those symptoms but I felt like it would probably have died within weeks and would've required a tow).

    I don't know how the newer Li-Ion will fare since those fluctuate in SOC more readily when new (that was a mental note I made when we swapped the Gen 2 for the Gen 4 with Li-Ion). But I suppose the still telltale sign is not being able to drive in EV mode since the SOC would drop at any attempt vs. a new Li-Ion battery. Anyway, no issues on the 2016 Gen 4 yet even though it's coming up on 10 years.
     
    #65 Tideland Prius, Feb 16, 2026 at 7:27 PM
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