12 volt battery Cold Cranking Amps

Discussion in 'Prime Technical Discussion' started by D Beloy, Apr 4, 2020.

  1. D Beloy

    D Beloy New Member

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    The battery in my Prius Prime says 295CCA(EN) and this morning at the dealer , they tested the battery and it is putting out 344CCA. Does that make sense? It is rated at 295 and it is putting out 344. I called their parts department and their replacement battery which costs about $180 has a rating of 470CCA. I’m confused. Why does the label on the battery that is installed in my prius saying 295 but it is putting out 344? Do I need my battery replaced by the dealer? The battery did say (EN) which means European Norm. So what does that mean? Thanks for your thoughts on this issue.
     
  2. schja01

    schja01 One of very few in Chicagoland

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    I think cold cranking amps is almost meaningless as it doesn’t need much more than two lantern batteries to “start”. The traction battery does all the heavy lifting. The 12 just boots the computer and powers some 12v accessories when not in READY Mode.
     
  3. sam spade 2

    sam spade 2 Senior Member

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    It tests BETTER than nominal. Why would you think that is a problem ?
    It isn't.
    BUT that alone isn't a really good test either.

    Why are you having it tested in the first place ?
    At only 2 years old, it likely is just fine.
     
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  4. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    "Cold Cranking Amps (CCA) CCA is a rating used in the battery industry to define a battery's ability to start an engine in cold temperatures. The rating refers to the number of amps a 12-volt battery can deliver at 0°F for 30 seconds while maintaining a voltage of at least 7.2 volts." - Cold Cranking Amps (CCA) | How to Choose Your Battery | Autobatteries.com | Clarios

    I am betting it was not 0°F in Hawaii.
     
  5. Elektroingenieur

    Elektroingenieur Senior Member

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    Yes; as @JimboPalmer kindly pointed out, the test conditions were probably more favorable than those used to determine the rating on the label. As long as the battery can provide at least its rated current, the CCA test passes. Other tests might pass or fail, depending on the battery’s condition.

    As @schja01 kindly mentions, the auxiliary (12-volt) battery on a Prius car is never required to deliver its full current, since the engine is started by MG1 in the transaxle, using energy from the much larger HV battery, but CCA remains a useful measure of battery performance.

    In the Repair Manual (more info), Toyota writes, “When replacing the auxiliary battery with a new one, use an auxiliary battery with the same physical dimensions (LN 1), a cold cranking ampere (CCA) 295 A or more, and a 20-hour rate capacity of 45 Ah or more.”
    Not unless there’s some other problem that you haven’t told us about.

    If you do need a replacement, it doesn’t have to be from a Toyota dealer, unless they’d provide it for free under warranty. Batteries of the correct size and rating are now widely available; see my January 2019 posting.
    My posting linked above discusses the EN battery standards.
     
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  6. Mendel Leisk

    Mendel Leisk Senior Member

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    It's very normal for a battery to measure higher than rated CCA. If it were lower, then I'd get concerned.
     
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