12v Battery Age?

Discussion in 'Prius v Care, Maintenance and Troubleshooting' started by kevinprius416, Nov 19, 2025 at 10:37 PM.

  1. kevinprius416

    kevinprius416 New Member

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    I picked up a 2015 Prius V the past summer with 130k km (80k miles) which had all service done at a Toyota Dealer. I decided to check on the 12v battery to figure out the age and if I should replace it now that winter has rolled in. I believe the original 12v battery is in the car, 311014 is the code if I'm not mistaken. There is also a 2434 stamp on the casing which could be a 2024 battery?

    Car has had no issues starting or exhibiting any weird electrical issues/inconsistent codes. I do fully intend on replacing the battery if the date code is indeed 2014.

    priusv-battery-date.jpg
     
    #1 kevinprius416, Nov 19, 2025 at 10:37 PM
  2. rjparker

    rjparker Tu Humilde Sirviente

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    Looks pretty new. Can't be a 2014 - they don't last that long.

    The definitive test is an old school load test, usually free at an auto supply.
     
    #2 rjparker, Nov 19, 2025 at 11:43 PM
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  3. Mendel Leisk

    Mendel Leisk MMX GEN III

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    I’d load test it (with one of the electronic load testers), go from there.

    last battery I put in our 2010 was September 2015, still testing like new. I’m using a Solar BA5 (latest iteration Solar BA9).

    note, the pictured battery is an Optima Yellow-Top, with 450 CCA spec, and maybe 38 Amp Hours. Not really optimal for Prius; when I replace it I’ll go with something with specs closer to original, say 325 CCA, and higher Amp Hours.
     

    Attached Files:

    #3 Mendel Leisk, Nov 20, 2025 at 8:04 AM
    Last edited: Nov 20, 2025 at 8:41 AM
  4. VelvetFoot

    VelvetFoot Active Member

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    While I've never used the old school tester, I have a digital tester and based on my experience, wouldn't trust that too much. It's easy and cheap, but I'm not sure how accurate. Which type do the auto supply places use? I suppose it varies.
     
    #4 VelvetFoot, Nov 20, 2025 at 8:57 AM
  5. BiomedO1

    BiomedO1 Senior Member

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    If that car was always dealer serviced; you should be able to pull up the history through it's VIN.
     
    #5 BiomedO1, Nov 20, 2025 at 9:42 AM
  6. rjparker

    rjparker Tu Humilde Sirviente

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    If the "old school" load tester (still available everywhere) has analog meters and ventilation it is more likely to be accurate. The better units are called "carbon pile" load testers.

    Image.jpeg
     
    #6 rjparker, Nov 20, 2025 at 12:40 PM
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  7. BiomedO1

    BiomedO1 Senior Member

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    I think harbor freight still has the lower pictured one for around $20; pretariff price. That intel is more than a year old....:(
     
    #7 BiomedO1, Nov 20, 2025 at 12:46 PM
  8. rjparker

    rjparker Tu Humilde Sirviente

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    The David Letterman Battery Tester

     
    #8 rjparker, Nov 20, 2025 at 1:18 PM
    Last edited: Nov 20, 2025 at 1:36 PM
  9. kevinprius416

    kevinprius416 New Member

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    I borrowed an analog load tester and ran a 10s test after driving the car a good 25km (i.e. 12v battery should be charged). The load tester indicated "weak" which is below 200 CCA on this tester. With temperature compensation from the chart on the tester and the ambient temperature at time of test, I should be removing about half step, so I guess it's (weak - 1/2 step) = still weak? :)


    In Canada, Toyota does not have the service records online unfortunately. I flipped through the paper invoices from Toyota and none were for a battery, I even called the servicing dealer and they said it was never done.

    I also emailed Yuasa asking how to read the manufacturer date and they indicated Oct 31 2014 is indeed the manufacture date. I was a bit surprised they answered my inquiry so quick.

    So either the previous owner replaced the original Yuasa battery with another 2014 Yuasa and some how it still works, or it is the original 11 year old battery that still works... The battery build date also makes sense based on the build date of the car.

    I'm going to replace the battery, appreciate the tips and ideas!
     
    #9 kevinprius416, Nov 20, 2025 at 5:14 PM
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