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Replacing Optima 12V with Toyota OEM 12 V battery

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by kabiblueline, Nov 9, 2023.

  1. kabiblueline

    kabiblueline Junior Member

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    My '05 Prius has an Optima yellow top 12 V battery that has lasted for 12 years, but it needs to be replaced.
    I've already purchased a Toyota OEM as a replacement. But I have run into a couple issues:
    1) I forgot that I must have done the conversion to SAE terminals ( and the original parts are long gone ). Are the shims that convert JIS to SAE an acceptable solution, or should I really get new JIS terminals?

    2) For the life of me, I can't get the vent tube out of the Optima. I know these are not easy to come by, so I'm trying to be as gentle as possible while wrenching on it. Any tips for getting it out of there? Will the vent tube in the Optima fit the OEM?
     
    #1 kabiblueline, Nov 9, 2023
  2. dolj

    dolj Senior Member

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    The OEM vent tube (that I believe is also accepted by the Optima) is a bayonet-type fitting so it just needs to be turned (I want to say ΒΌ turn anticlockwise) and then pulled out.
     
    #2 dolj, Nov 9, 2023
  3. Tombukt2

    Tombukt2 Senior Member

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    I've not had a vent tube since I've gone to gel and AGM battery some time ago. And I haven't died yet or smelled any funny fumes so I'll take it that everything is okay My later model HV battery also does not have the vent tubes holes or the two running out the side of the chassis and down into the floor anymore It's all been plugged up with factory rubbers from cars that don't have the vent so on and so But the vent tube generally snatches out of the battery and plugs right into the new one If it breaks I think they're pretty much readily available I thought the optima came with one attached to its plastics look carefully for you throw them out.
     
    #3 Tombukt2, Nov 10, 2023
  4. kabiblueline

    kabiblueline Junior Member

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    I've seen that there has been discussions about the necessity of a vent tube.
    I guess I figured I have a perfectly good one, why not just put it on the new battery (which does have a hole for one).
    Certainly no harm done.

    But I cant' get the darn thing off.

    I don't think it is a bayonet fitting, because it rotates freely 360 degrees.

    The mechanic at the dealer parts shop encouraged me to keep mine, because he said they are "impossible to get".
    I took the old battery home instead of leaving it with him to recycle, just so I could get the tube off.
    A quick search found one for ~$13 with $50 shipping... no thanks.
     
    #4 kabiblueline, Nov 10, 2023
  5. bisco

    bisco cookie crumbler

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    it's a safety feature in a rear accident
     
    #5 bisco, Nov 10, 2023
  6. Tombukt2

    Tombukt2 Senior Member

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    If you have an accident in the rear and you get your rear quarter crushed your battery is probably going to be cracked I doubt any venting is going to be going through the tube it'll just be going right through the big gaping hole that's been cracked into your plastic case of your battery pretty simple but the fumes you'll be out of the car long before you have to worry about AGM battery fumes. The vent tube usually you can take a pair of long needle nose turn the rotating fitting so it's level with the top of the battery apply the long needle nose at the very base under the neck and against the battery squeeze the needle nose gently while prying against the battery to pull the bung out of the battery.
     
    #6 Tombukt2, Nov 10, 2023
  7. kabiblueline

    kabiblueline Junior Member

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    Followup: I was able to remove the vent tube from the Optima battery with constant steady pressure.
    However, that vent tube does not fit in the OEM TruStart battery.

    So, for now, I'm going tubeless.
    Otherwise, the OEM battery worked perfectly for me. I apparently had SAE-sized terminal connections (which I must have added when converting to the Optima 12 years ago.. but I cant' remember what I had for breakfast, so I definitely don't remember that...). Just bought some cheap post adapters on Amazon and they did the trick.
     
    #7 kabiblueline, Nov 20, 2023
    bisco likes this.
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