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Replacing the 12v battery in a 2009

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by jsquareg, Oct 22, 2010.

  1. jsquareg

    jsquareg New Member

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    I want/need to replace the 12v battery in my 2009 Prius. I know where it is located but would like to find instructions on how to remover it and put the new one in. I have found a lot of discussion here in the forums and elsewhere on the web but none have been specific to the 2009. Is there any special thing I need to know?

    The replacement Optima with the installation kit is on order.

    Thank you.
     
  2. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    The 2004 to 2009 model years, called Gen II, should all be the same in this regard.
    You should see a number of existing Gen II 12 v battery replacement threads just below the Quick Reply box.
     
  3. jsquareg

    jsquareg New Member

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    Thank you. I thought that might be the case.

    And, I had seen those threads during my search for info.
     
  4. 2009Prius

    2009Prius A Wimpy DIYer

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    Shouldn't it still under warranty?
     
  5. ETP

    ETP 2021 Prime(Limit),24 Venza Limit,B52-D,G,F,H

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    Is this covered under the 3/36?
     
  6. richard schumacher

    richard schumacher shortbus driver

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    The Optima kit from eLearnaid comes with completely detailed instructions. If that's what you ordered then no worries. If not, then, ehh, maybe the instructions are posted on their website.
     
  7. MJFrog

    MJFrog Active Member

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    I just replaced my wife's battery with this kit. Being a complete amateur with this process (a standard battery for a non-hybrid is child's play to this), it took me the longer end of the time range (1.5-2.0 hrs). :(

    There was nothing horribly confusing, difficult, or mysterious about it...just that I wished I was a lefty instead of right-handed. I could have saved half the install time if I were. And of course, during the very last step I dropped my 10mm socket down in the battery well. Which is where it will stay until I change the battery again in about 5-6 years. :pout: The instructions that came with the kit were very good, but I would have liked a few more pictures detailing some of the steps.

    I made an attempt to save the car settings by hooking up a low-amp 12v charger on the front jump terminals, but maybe it didn't have enough juice to save the settings...I lost them.

    I'm glad I read in another thread about the sparking that occurs when you connect the negative lead. I'd probably have had a heart attack trying to hook that thing up. It's possible my clumsiness connecting it to the body could have lost the car settings too. :confused:

    If I had it to do over again, I think I would connect the negative lead to the car body before I connected it to the battery.

    Anyway, it's finished and I didn't destroy her car in the process. It will need to charge for a while, since I've had the Optima just sitting around for a few months in anticipation of needing to change out either hers or my battery.
     
  8. Patrick Wong

    Patrick Wong DIY Enthusiast

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    1. You may find that a telescoping wand with a magnetic tip on the end will help you to retrieve that socket, as well as misc hardware that you might drop from time to time as you are working on your car. (I've used this tool a few times and am glad to have it in my toolbox.)

    2. Is it possible that the charger will refuse to provide voltage when the battery is disconnected? Many chargers work that way.
     
  9. 2009Prius

    2009Prius A Wimpy DIYer

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    I thought the reason for connecting the negative cable to the body last is that the spark will be farther away from the battery. Making the last connection at the battery would introduce the spark right there and risk igniting hydrogen gas that occasionally escape from the battery.
     
  10. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Yes. Also as a practical matter, it is harder to access the battery's negative terminal while the battery is mounted in the car. It is much easier to remove the negative lead at the body, remove the battery (after disconnecting the positive terminal and the mounting bracket), then disconnect the negative cable from the battery and swap over to the replacement battery.
     
  11. PoutyPrius

    PoutyPrius New Member

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    Jealous! How did you get the 12mm bolt off of the positive terminal on the metal arm that goes in to the fuse box? I had that thing solidly clamped on my table saw table (bad idea) and almost busted it off. Was it easy to get off for you? Mine is a 2005. Let me know if you have any tips!
     
  12. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Maybe it might help to try loosening that nut while the positive terminal connector is still attached to the old 12V battery, so that you are using the battery and the car as your "vise".

    Of course, disconnect the negative terminal side first so that in case your wrench contacts the car's body you won't cause a big spark.
     
  13. MJFrog

    MJFrog Active Member

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    Didn't really expect to come back to this thread...

    As Patrick says below, I loosened the bolt before I took the pos terminal off. Bent the metal strip a bit, but it straightened back out using a couple pairs of pliers.