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Can I recharge my 12V battery?

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by sherlockcrypto, Jan 20, 2022.

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  1. sam spade 2

    sam spade 2 Senior Member

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    Well that's a pretty good point actually. (y)

    But I would hope that the electronics in the car are designed well enough so that they will NOT come on just from the application of operating power.
     
    #21 sam spade 2, Jan 21, 2022
  2. sam spade 2

    sam spade 2 Senior Member

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    Not true.
    It can, and probably will, charge just fine at a voltage somewhat below that.
    If the nominal float voltage of your battery is 12.8, it will charge with the application of any voltage above 13.4.
    Slowly maybe but some.
     
    #22 sam spade 2, Jan 21, 2022
  3. sam spade 2

    sam spade 2 Senior Member

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    That is exactly how it is supposed to work.
    You are close to being done........hopefully.
     
    #23 sam spade 2, Jan 21, 2022
  4. Mendel Leisk

    Mendel Leisk Senior Member

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    One of the array of electronic 12 volt battery testers is what you need, to assess the battery's health. Watching a charger struggle with it doesn't really tell you that much. I use an older Clore Solar BA5; current itteration is BA9, and there are lots of choices. Antec is popular I think. These sorts of testers are what the dealership use, and automotive retailers. The latter will typically test for free.

     
    #24 Mendel Leisk, Jan 21, 2022
    Last edited: Jan 21, 2022
  5. sherlockcrypto

    sherlockcrypto Junior Member

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    Thanks for the replies everyone. I've learned a lot about car batteries the past few days.
    After charging overnight, the charger shows 100%. Multimeter is showing 12.92V

    This is an AGM battery btw. So from what I am figuring out is that even at 12V, the other metrics like CCA might not be good enough? or that it will lose charge quickly? I will bring it to an Autozone near me for a battery health check...

    With Prius however, my understanding is that we don't need that much CCA since all the battery does is start the system, not the engine? The battery i am using is rated for 325 CCA.

    I will let it sit for a few days and then see what the voltage is then to see if it loses charge quickly. Hopefully it should still start prius.
    I am also wondering how long the car battery can last if i keep doing this? Is it possible to have the car battery last 10+ years? I am already at year 7, averaging only about 7000 miles per year, as I am a light driver. Even if only at 50% health, if i can get another 3 years, that is a win in my book...

    upload_2022-1-21_11-36-32.png
     
    #25 sherlockcrypto, Jan 21, 2022
    Mendel Leisk likes this.
  6. sam spade 2

    sam spade 2 Senior Member

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    Not really. The "nominal" fully charged voltage for an AGM usually is about 12.8 to 12.9.
    12.0 is about 50% discharged.
    Those tenths of a volt are important.

    You have a good plan. Just keep an eye on it for a few days.
    But at 7 years old it is on borrowed time.
     
    #26 sam spade 2, Jan 21, 2022
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