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Question re: 12-volt battery, please?

Discussion in 'Gen 2 Prius Main Forum' started by Julia2001, Aug 14, 2012.

  1. uart

    uart Senior Member

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    I agree with this. They may replace it out of good will, or to a avoid a "scene", but if they want to dig their heels in then they will go by a strict pass/fail test.

    They'll first charge it and then apply some load tests and it will either pass or fail, and the voltage that it reports in a Prius wont even enter into the equation. I'm about 99% certain that if they give it a pass/fail type test then it will pass.
     
  2. Note, reply above.
     
  3. As for 12 Volt Battery being a stickey, I concur, should have been a long time ago.
     
  4. dorunron

    dorunron Senior Member

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    Julia2001, for the record what was the final outcome on your "Yellow Top" battery. What did you finally end up doing?
     
  5. Julia2001

    Julia2001 Member

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    Nothing yet. I'm taking readings and writing them down daily so that if necessary I can present them to Advanced Auto should I find that my battery does not charge sufficiently...I have been taking some longer trips this past week and have another even longer trip for work this week.

    So far the battery is still not where it should be.
     
  6. dorunron

    dorunron Senior Member

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    There is such a thing as a "load test". It is similar to what you do when you check the voltages with the MFD and noting the voltages at the various stages (accesory, ignition on). In post #301 uart did mention that. Based on what you have said and reported in the past, I think it would be wise to get a second opinion from someone who has a good battery load testing machine. Most good mechanics (car repair) shops/centers will have that machine. It would not surprise me if one of those shops would perform the load test for free if you asked nicely. If you have the time, it might be a good idea to get the battery load tested. If it fails, have that individual record that in their records and get a copy of it. If it passes, then I would consider going on down the road with the battery you have.

    If you do try to return it, more than likely they are going to do what uart said: charge it and then run a load test. If it passes, they probably won't give you a new battery, but if it fails then they should exchange it. The longer you wait, the more chance of you paying a pro rate amount on the exchange.

    It is a shame that you seem to be having problems with the new yellow top. I would think by now the battery would be charged up as it has been a while since you installed it.

    Best of luck to you.

    Ron

     
  7. Julia2001

    Julia2001 Member

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    My test today...after ALL THAT DRIVING over the past few days...

    12.1 / 11.9 / 14.0
     
  8. dhanson865

    dhanson865 Expert and Devil's advocate

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    all that driving? Was it one long trip or did you turn the car off repeatedly? Every time your car goes from Ready to Off and from Off to Ready it drains the battery enough to offset a short to medium length trip. Only long periods in READY mode without turning the car off and back on will help to charge the battery and then only if you don't have a large load on the 12v system.

    Did you have your headlights on? Radio? AC or heat? Cell phone charger, GPS, or satelite radio? Radar detector? Aftermarket alarm system? Defroster? Leave a turn signal on for half the trip?

    The prius charging voltage is rather weak vs the possible load you can put on the battery (they did increase the charging voltage for the Gen III 2010 and newer, but us Gen II 2009 and older drivers have to put up with a slower charge rate). I wouldn't expect the Gen II Prius to charge a battery to anywhere near full unless you unplug/turn off every possible power drain the entire time you use the car for an extended period (probably a few weeks, maybe months depending on the time in READY mode per trip).

    Put it on a smart charger and it can be charged in a day or two.

    Even then if you have a non standard load on your Prius 12v bus the voltage on the MFD will appear to be lower no matter how good the battery.
     
  9. Julia2001

    Julia2001 Member

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    No, I drove about 100 miles one way...turned off the car. Left it for a few hours, and drove 100 miles back.

    The next day I did the same, only about 75 miles each way, and the following day two 45 mile trips.

    PLUS I already supposedly "fully charged" the new battery using a charger for 9 hours.

    It should not be reading 12.1 volts and 11.9 volts from all I've read, including from the Optima rep himself.

    I'm not arguing...I'm just saying...No, I didn't drive three miles and stop, drive four miles and stop, etc. I took some trips, as I said.

    Sometimes I had the radio on and sometimes the AC, and that's all.

    And the best reading I've ever gotten from this brand new battery AT THE POSTS USING A DIGITAL MULTIMETER is 12.38.

    Good enough? Not by comparison to others here using the Optima Yellow Top and definitely not good enough according to the Optima rep.

    11.9 in Ig-On is what I was getting from my old battery from 2007!

    In ACC mode I was getting better than this!

    So - you can argue all you want that I should not expect better readings than this from my brand new battery, but I disagree, based on all I've read.

    With that said, I HOPE I'm wrong. I hope I have a delightful, superbly performing new battery here...but according to the voltage readings I've been measuring, that doesn't appear to be the case.
     
  10. uart

    uart Senior Member

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    Hi Julia. I agree that your voltages are lower than what I'd expect, but remember that these prius measured values are typically lower than the true readings taken with a voltmeter right at the battery terminals (in the rear hatch). Could you humor us and take a reading with your voltmeter right at the battery.

    BTW. The only thing that looks good about your reported battery voltage (12.1/11.9) is that the voltage drop at Ig-On was only 0.2 volts. Typically a small voltage difference here is a good sign that the battery internal resistance (a measure of battery ill health) is low.
     
  11. Julia2001

    Julia2001 Member

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    I have been taking that measurement (right at the battery with a digital multimeter) right from the beginning.

    12.38
     
  12. dhanson865

    dhanson865 Expert and Devil's advocate

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    At the battery with the battery sitting on the floor or in a box? Or at the battery while hooked up to the car?

    My higher reading was sitting on the floor of the garage not hooked up to the car.

    As soon as you hook it up the SKS and other systems start putting a load on it and lower the reading.

    I'm not saying your battery is good or bad, I'm just trying to make sure you understand some of the ways that checking a battery can give you a bum reading because you may not take a variable into consideration.

    In the end if you think it isn't up to snuff swap it or get a refund and buy a different brand.
     
  13. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Hi Julia,

    I think you've given your battery sufficient charging and driving time. If you want to replace it, my suggestion is that you initiate that process now.
     
  14. uart

    uart Senior Member

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    Ok 12.38 volts. What mode was the Prius in when that was measured, eg "off", "acc" or "ig-on"?
     
  15. hb06

    hb06 Member

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    My Optima 12V battery died within 1 year. Got a replacement at Autozone. I also could not get it charged up even after driving LA-OC. Checking the serial # which includes the Julian date, it was manufactured 1 year and 7 months ago-too old! A voltage meter also confirmed replacement battery was bad. They are now going to replace it again with a different Optima with a newer date. According to Optima, 7-8 months old is fairly normal or under 1 year. For some reason, there is a Plastic Sticker date on the battery which does not coincide with the Julian date. Got different answers from the store.
     
  16. hb06

    hb06 Member

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    My recent Optima replacement battery would not charge to the required voltage and was determined to be in bad condition with a voltage tester. The Optima Serial number includes a Julian date which is the actual date of manufacture. After receiving this replacement Optima from Autozone, the Sticker said January, 2013 but the Julian date was 1 year 7 months old! The store did not have an answer as to why the "Sticker" date was completely different from the actual date of manufacture as shown by the Julian date on the serial number. Am now getting yet another Optima replacement and verifying first the Julian date of manufacture. Under 1 year is acceptable according to Optima.