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Another 12v Battery Phantom Draw Thread

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by EastR, Jul 9, 2014.

  1. EastR

    EastR Junior Member

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    Recurring problem with my 12v Aux battery on my 2006 Touring. It is an Optima yellow-top purchased in October 2012 (less than 2 years old). One month ago after driving to work (45 mins) in morning, car would not start for drive home at 5pm. Jump-started to get home and left a trickle charger on the battery overnight until the numbers came up to an acceptable charge (per Diagnostic mode). Battery worked fine for 3 weeks, then went out of town for 4 days, returned and the battery was completely dead again. Able to jump again and get to work; returned to Advanced Auto Parts (where I purchased the Optima with a 3 year warranty) and they tested the battery which showed a 391 CCA out of the 450 so it tests "good" and they say cannot be replaced under warranty.

    Before the first dead battery I was frequently using the DC connector under the glove box to charge my iPhone while commuting. After reading the forums, I don't use the DC power anymore. Now I have turned off the key fob sensor under the steering wheel until I figure out what is drawing this phantom power from the 12V. Any more advice? My only other option is to buy a new Optima on Amazon for $147. Thanks!
     
  2. ursle

    ursle Gas miser

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    Contact optima, they piss me off but you might get a nice public relations person, yer battery isn't going to get better, replace it.
    The dc connecter under the glove box, is it hot when the car is off, if it is I'd kill it. Any accidents that would meld wires?
     
  3. EastR

    EastR Junior Member

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    Rear bumper parking lot scrape that required replacement of entire rear bumper. How to disconnect DC connector? I will check if it is hot. All other interior lights are off.
     
  4. nh7o

    nh7o Off grid since 1980

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    The DC connectors are switched off when the car is off, and charging your device while driving won't contribute to this situation. First thing is to read the battery voltage, using the inspection mode:
    Weird stuff happening? MPGs dropping? Test The Battery | PriusChat

    Report the values here.

    If you suspect a drain problem, the only way is to measure it. Use a digital volt meter, in amps setting, in series with the battery lead, and place it in a window so it can be seen from outside the car. After the doors are shut and the car sits for a bit, SKS off, the current draw should ~20 mA.
     
    #4 nh7o, Jul 9, 2014
    Last edited: Jul 9, 2014
  5. EastR

    EastR Junior Member

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    Great, I will hook up the mulimeter and report back later this week. Going to use alligator clips directly to the battery in the trunk and will also check the Diagnostic screen for voltage numbers.
     
  6. Easy Rider

    Easy Rider Active Member

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    It is important to note the voltage while driving too.
    Phantom drains are an extremely rare thing.
    In a situation like this, the battery is at the top of the list.
    Second is not being charged properly while driving.
    Third is a bad connection somewhere, often at the battery posts.
    WAY down on the list is a phantom drain.
     
  7. EastR

    EastR Junior Member

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    Battery numbers this morning before driving:
    ACC: 10.3V
    Load: 9.6V
    Charge/Start: 14.4 V

    Battery numbers after driving 45 min highway commute:
    ACC: 11.8V
    Load: 11.1V then over 5-8 seconds slowly drops to 9.9V
    Charge/Start: 14.3 V

    As a side note, going from ACC to Load before driving MFD shows "Caution - There is a problem with the transmission "P" lock mechanism. Park your car on a flat surface, and fully apply the parking brake." This intermittently shows up (once every two weeks?) and car still starts normally. I've searched the forums on this but heard reports of not being able to repeat the error at a mechanic and I've done all the regular maintenance (currently at 154k miles).
     
  8. css28

    css28 Senior Member

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    Replace your battery.

    Honestly, I'd stay away from Optima, given the behavior of your current one (and its early mortality).
     
  9. dolj

    dolj Senior Member

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    I second what css28 said on both counts.

    Your battery is toast and needs replacing--the caution message on the MFD is a dead giveaway. There are better alternatives than the Optima if you don't want to use OEM, but honestly the OEM is perfectly good choice and I'd recommend you consider using the larger one.
     
    #9 dolj, Jul 10, 2014
    Last edited: Jul 10, 2014
  10. EastR

    EastR Junior Member

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    Local dealership has the OEM - Part # 28800-21171 for $192. I'll probably go that way unless there's any other way to convince Advance Auto to replace the Optima under warranty (i.e. free).
     
  11. Mike500

    Mike500 Senior Member

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    From reading through all the threads on the Optima battery, it appears that the OE replacement battery is worth the extra cost as the savings from others is not worth the $50 or so in savings.
     
  12. EastR

    EastR Junior Member

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    Another local dealership has this battery for only $153. Does it look right? I have the 2006 Touring but I think it should be the same as the 2007.

    2007 - Toyota - Prius Touring - 1NZFXE - L4 - 1.5L - ELECTRIC/GAS
    ELECTRICAL / ELECTRICAL / BATTERY / Battery
    0054421171325 - Battery 12 VOLT, w/"Smart key"
    PARTS: Battery marked S46B24R.MSRPCoreOnline Price
    $192.13$0.00$153.70

    Part Discontinued
    Part Superceded to 0054421171325
    View Part Diagram -- Item #1
     
  13. dolj

    dolj Senior Member

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    Yep, that looks like the one -- S46B24R