Key Battery Low

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Mauiman, Dec 3, 2015.

  1. Mauiman

    Mauiman Junior Member

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    I have changed the key battery before in the past with not experiencing this issue. Recently, I got the key battery low warning when parking the car. I replaced the existing battery with a new, fresh battery. All was well for about a week or so. Yesterday, I started getting the key battery low warning again.
    I'm not sure why I am getting that message again after replacing with a new fresh battery?
     
  2. wjtracy

    wjtracy Senior Member

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    Gotta assume battery is low. It is easy to short out these batts. Another issue is if its too close to the car. Probably need to try another batt and visually check inside for any fuzz or anything that might bridge the gap of the battery.

    PS- what battery are you using for Gen3? (CR2032? etc)

    PSS- Is the warning light for the key fob battery? I don't recall that.
     
  3. jdcollins5

    jdcollins5 Senior Member

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    If you are buying the cheap Chinese batteries this may be a problem.

    I bought two different Rayovac batteries from Walmart with Made in China on the battery. I had to replace them in less than 3 months.

    If you can find a Duracell battery they seem to last the longest.
     
  4. bisco

    bisco cookie crumbler

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    how many have you put in? mine are original from 04/12.
     
  5. jdcollins5

    jdcollins5 Senior Member

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    It is not a warning light. The Gen 3 gives a "Key Battery Low" message in the display.
     
  6. wjtracy

    wjtracy Senior Member

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    I use a lot of these in electronics projects, and I saw this recently:
    CHOOSING A BRAND…Hundreds of brands claim to be the best battery but only Energizer, Duracell, Rayovac and Ultralife can live up to this promise.These leading manufacturers produce the most trusted, dependable, high performance alkaline and lithium batteries on the market and are the very best replacement batteries for critical applications. To choose the best battery from these excellent brands, try each kind of replacement batteries and keep track of the life you get from each. One of these top brands is sure to be the best battery for your needs.

    I have seen the Energizer CR2032 to be good. I assume SONY/PHILIPS and the like are good names. On Amazon you can get these really cheap if you plan ahead and get multi-packs.

    Interesting batt tests, he did find a few bad ones
    How much energy can you really get from a coin cell? | Embedded

    http://data.energizer.com/PDFs/cr2032.pdf
     
    #6 wjtracy, Dec 3, 2015
    Last edited: Dec 3, 2015
  7. David Beale

    David Beale Senior Member

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    So at two to three years for each battery (cell, actually), it should only take you, what, 12 years to figure out which one is best by trying them out and recording the life? ;)
     
  8. milkman44

    milkman44 Active Member

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    I've replaced two Walmart Rayovac batteries within three weeks of use and those dudes were 6dollars apiece. Switched to Panasonic @ 5 for $6.00 and no more low battery warnings.
     
  9. Mendel Leisk

    Mendel Leisk Sand Pounder

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    A digital voltmeter will help too, to verify the condition of these "new fresh" batteries. That said, the voltage doesn't seem to vary much, between brand new and dud.
     
  10. bisco

    bisco cookie crumbler

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    seems to be mostly duracell around here, no prolemo.
     
  11. wjtracy

    wjtracy Senior Member

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    Fresh Voltage is about 3.1 volts...whereas 2 volts is considered dead. I suppose it could be possible to have a low quality batt that looked good (3.1 volt) but had shorter life, but I have not seen that documented. The article I posted the guy saw equiv. performance in Duracell, Panasonc, Energizer except he found a few duds.
     
  12. Mendel Leisk

    Mendel Leisk Sand Pounder

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    I've had the car warning about low fob battery come, and checking the voltage I got 3.0, maybe ticking down to 2.9. They're fussy I guess.
     
  13. David Beale

    David Beale Senior Member

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    You guys just had to post this thread! ;) Got my warning this morning. It's time, 3 1/2 years. Hunting for CR1620s now.
     
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  14. wjtracy

    wjtracy Senior Member

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    oh CR1620's
     
  15. DumbMike

    DumbMike Active Member

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    Power of suggestion? Maybe the batteries are starting their own union? If I get my warning within the next week, there will be some major discussion on this topic.

    Mike
     
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  16. bisco

    bisco cookie crumbler

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    gen I = CR2016 gen II = CR2032 /gen III = CR1632 gen IV = we'll cross that bridge when we come to it?
     
    #16 bisco, Dec 4, 2015
    Last edited: Dec 4, 2015
  17. jdcollins5

    jdcollins5 Senior Member

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    Each time I have received the Key Battery Low message the battery has measured right around 3.0V. A new, fresh CR1632 battery will measure 3.3V. I do not know how much longer the key fob will continue to work after receiving the first low battery message. I do not really want to find out, especially for my wife to find out.
    • My OEM battery lasted right at 3 years. Replaced with Radio Shack batteries.
    • Radio Shack batteries only lasted 2 years. Replaced with Walmart Rayovac Chinese batteries. Measured 3.1V new.
    • Only 2 1/2 months on first Rayovac battery. The 3.1V should have been an indication of early failure. 3.32V on new Rayovac.
    • 9 months on the second Rayovac battery. Replaced with Nuon batteries from Batteries Plus. Made in China!
    When the Nuon batteries need replacement I plan to find Duracell for the next replacement, even if I have to order from Amazon.

    Interesting when I saw the Nuon batteries at Batteries Plus were also made in China I told the sales guy about my issues with the Rayovac. His comment was that all of them were coming from China!!
     
  18. wjtracy

    wjtracy Senior Member

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    I have a Panasonic CR1632 from Amazon recently I get 3.27 Volts
     
  19. fuzzy1

    fuzzy1 Senior Member

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    My original also dated to 4/12, had to replace it 8/15. The spouse's fob was giving no warning, but since the voltmeter found it was getting low, I replaced that too.
    I'm seeing a 6-pack of Duracell CR2032s at Sam's Club for $9. Unfortunately that is not the right size for my Gen3, but is the right size for our bicycle computers and some other devices.

    If you Gen2 folks use that size ...
     
  20. Mauiman

    Mauiman Junior Member

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    I used CR1632 battery as a replacement and just replaced it about 2 weeks ago. I get the key fob battery low message when shutting down the engine and parking. I am surprised how often I have to replace the key fob battery - for a 2011 car, I'm now on my 3rd battery (original + 2 replacements).
     
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