12v Battery Charger recommendation?

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by bobzchemist, Aug 25, 2017.

  1. Grit

    Grit Senior Member

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  2. sam spade 2

    sam spade 2 Senior Member

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    IF.....it is has a well designed "automatic" function, the total capacity is pretty much meaningless because it will reduce the charge as needed depending on the charge in the battery.

    Most have a fairly low capacity because that is all you need to maintain a battery that starts out fully charged.

    You should NOT leave a non-automatic "trickle charger" continuously connected to a battery, no matter what the capacity.
     
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  3. Rocky Mountain Priusman

    Rocky Mountain Priusman Active Member

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    Do you have any simular concerns about leaving the HV battery for days not in use? How much can it handle sitting around? I know multiple months of inactivity is bad for the HV battery, but let's say you only drive the car once a week?
     
  4. Mendel Leisk

    Mendel Leisk MMX GEN III

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    Ours is behaving like new still, and it sits multiple days, often a week. The 12 volt with suffer without a charger though, in that scenario.
     
  5. CR94

    CR94 Senior Member

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    Not a problem, assuming it starts with moderate charge level.
     
  6. sam spade 2

    sam spade 2 Senior Member

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    Entirely different battery chemistry.
    Entirely different situations.
    So the answer is: NO.
     
  7. Bill Norton

    Bill Norton Senior Member

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    It depends on what kind of HV battery you are talking about.
    A Gen 3 Prius has a Ni-Mh chemistry, which has a known 'self-discharge' rate. You can look this up.
    A Li-ion pack has very little self discharge.

    It's the 12V that has duties to power when sitting around.
    It's nice to have a 'Battery Minder' on it if you're leaving it for a long time.
    I recommend that brand and have the 2A version with the 'desulfator' function. I put it on all my 12V's around the ranch for a few days, about once a month or so. I seem to be getting great 12V life from those batteries.
     
  8. LoveourPrius

    LoveourPrius Junior Member

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    Has anyone ever had any luck with reviving or de-sulfating a 12 V AGM battery?
    If so then how reliable was the revived AGM battery?
    How many months or years did it last?

    I've tried the "Repair" and the 'Force Charge' features of the NOCO Genius5 charger / maintainer with no success. I also tried the Schumacker SC1359 with no success.

    Next I will try a good AGM battery in parallel with the failing battery to see if it tricks the 'smart' charger into charging the failing battery.
     
  9. Prodigyplace

    Prodigyplace 2025 Camry XLE FWD

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    or the low cost involved, just replace it. When my son had his 2005 Prius, he replaced the AGM battery after 8 years because he did not want to get stranded away from home. He found it cheap insurance.
     
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  10. ASRDogman

    ASRDogman Senior Member

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    It's dead, let it rest in peace. They don't last forever...

     
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  11. rjparker

    rjparker Tu Humilde Sirviente

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    The answer is no. The 12v battery charger in your car is as good as it gets and that applies to worn out nimh modules as well.

    In the case of nimh batteries, a "reconditioned" is simply one where the bad modules have been replaced with slightly better used modules and maybe cleaned up bus bars. Which you can not do on a sealed lead acid or agm battery.
     
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  12. Mendel Leisk

    Mendel Leisk MMX GEN III

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    Maybe just get a battery tester? I’m using a Solar BA5; the latest iteration is Solar BA9. There’s various other brands.

    You typically set battery type and rated CCA, run the test and in a split second it displays tested CCA, voltage, and a verdict.
     
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  13. LoveourPrius

    LoveourPrius Junior Member

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    Thanks for the replies. I'll swap it for a good 12V, and will pick up a SOLAR BA9.

    Re: nimh cells - Is there an easy way to test the strength of nimh cells to determine which ones to swap.
     
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  14. Mendel Leisk

    Mendel Leisk MMX GEN III

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    That tester's made by Clore, which is as American as they come, headquartered in Kansas City, Missouri. I wouldn't be surprised if those tester are made for them in China though.

    That said, the BA9 is readily available on Amazon.ca, but on Amazon.com (US site), there's the apparently identical tester, but without the term "BA9". Not sure why, could be just some badging vagary, not sure.
     
    #54 Mendel Leisk, Sep 7, 2025 at 11:58 AM
    Last edited: Sep 7, 2025 at 12:04 PM
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  15. ASRDogman

    ASRDogman Senior Member

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    Make sure you charge the new 12v at 5amps or less for 6-8 hours so it has a full charge.
    They never charge them so they slowly discharge, you want to start with a fully charged 12v battery.
     
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