Best way to mod 12v terminals?

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by ryguy, Oct 14, 2021.

  1. ryguy

    ryguy New Member

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    I purchased a deep cycle 35AH AGM motorcycle battery that has flag posts on it. Obviously the prius uses JIS connectors. Now, keep in mind, I am NOT mechanically inclined WHATSOEVER, I am HORRIBLE with tools. It doesn't matter how many youtube videos I watch, it is just something I am not good at. With that in mind, what would be the easiest way to make this connection work? Would it work to drill through the JIS connectors and put my screw/bolt through that hole and through the hole on the flag post?
     
  2. TMR-JWAP

    TMR-JWAP Senior Member

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    Now, keep in mind, I am NOT mechanically inclined WHATSOEVER, I am HORRIBLE with tools. It doesn't matter how many youtube videos I watch, it is just something I am not good at. With that in mind, what would be the easiest way to make this connection work?

    Acknowledging this is half the battle for you. I just question, with this knowledge you have, why would you buy a non-direct fit battery that requires more than just simple installation? Now you're looking at jerry rigging the 12v connections. Although simple, the 12v connections are some of the most important connections in the vehicle.

    That being said, and assuming that perhaps this was the only option for you, take a look at some postings by @PriusCamper . I believe he has used batteries with a similar type top connector.
     
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  3. PriusCamper

    PriusCamper Senior Member

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    Not sure what you mean by "flag posts?" Can you share a link to what your terminals look like?

    In general I've found a big washer on the top and bottom of each battery terminal in your Prius will allow you to sandwich the terminal between them and bolt it down.
     
  4. dolj

    dolj Senior Member

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    Flag terminal:

    upload_2021-10-15_12-36-26.png

    You could get some adapters like these: Flag to Post Adapter. These likely will be SAE posts, so you might need to file them thinner to make JIS posts - caution! The lead filings are potentially toxic, handle and dispose of with care. I couldn't find any JIS sized adapters.

    Another option would be to use the existing bolt and clamp and undo the nut, open up the gap, sandwich the flag terminal between, then bolt it back up. That may not be possible, due to space, with the flag oriented as shown above.
     
  5. PriusCamper

    PriusCamper Senior Member

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    I saw a tik-tok video once where a guy arc-welds the terminal to the battery. That could work. :) Of course it'll wreck the battery and maybe the car too.
     
  6. ryguy

    ryguy New Member

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    Because the price for one is absolutely ridiculous. I bought this battery for 60 bucks with a 2 year warranty.
     
  7. ryguy

    ryguy New Member

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    This is the exact battery: [​IMG]
     
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  8. burrito

    burrito Member

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    The terminal clamps have a bolt and nut which you're supposed to tighten when you place the clamps over the battery terminals. You can use that bolt to go straight through the flap post, thereby attaching the clamps from the side, rather than actually clamping them onto anything. You may have to use your own bolt and nut. Maybe add washers.
     
  9. ryguy

    ryguy New Member

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    I'll try this. If that doesn't work, do you think I could just make sure those connections are touching and then tape it up tight with electrical tape to ensure they stay connected? I've never heard of anyone doing this but wouldn't it achieve the same result?
     
  10. dolj

    dolj Senior Member

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    No. Just don't.
    There's a good reason for that.
    No.

    The connections need to be bolted.
     
  11. Another

    Another Active Member

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    Tape it?
    Yikes!
     
  12. TMR-JWAP

    TMR-JWAP Senior Member

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    This question, all by itself, explains exactly why you should not have bought this battery. I recommend you just connect it with giant alligator clips and call it a day.
     
  13. xliderider

    xliderider Senior Member

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    Do it, if you want to create electical arcs between the poorly connected terminals/cables that can burn the tape around it and cause a fire.

    Your call...

    Posted via the PriusChat mobile app.
     
  14. koco

    koco Member

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    You could get a couple of these copper pipe clamps and use a nut and bolt to attach them to the flag posts. You will probably have to drill all the holes a bit larger. The positive one will bolt right on to the car's connector once you remove the battery clamp from it. The negative side could be attached with a cable that has ring terminals on either end as long as its an 8ga. cable at least. It is not science of rocket by any means. As long as you have good connections, the car will never know the difference.

    And make sure you get a dirty chunk of 2x4 to put under the battery hold down since the 35ah battery is slightly shorter than the original.

    This solution is no worse than most of the battery terminals I've seen in cars, especially the kind with the 2 little bolts on top that clamp down on crusty green frayed cables.

    pipe clamp.jpg
     
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  15. ryguy

    ryguy New Member

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    So, really strange behavior has happened with my Prius when I went to go replace the battery. It went from not even responding to my key fob lock/unlock to firing right up the next day when I put key in ignition. I'm now wondering if the battery perhaps isn't the problem and it's the connections themselves. Something also strange is that typically the key will not move when the car is on and in the ignition, but I made a glancing blow on the key and it wasn't locked into the ignition like typical, it was able to move freely? Anyone know what this behavior might be a symptom of?
     
  16. Another

    Another Active Member

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    Makes me wonder if this OP is just a hoaxer. Surprised he isn’t trying twist ties or something.
     
  17. xliderider

    xliderider Senior Member

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    I know people who put duct tape on everything.

    Me? I'm partial to zipties.

    Posted via the PriusChat mobile app.
     
  18. burrito

    burrito Member

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    Check the connection of the ground wire between the 12V battery and the body of the car. All connections should be snug and free of corrosion (or tape, or zip ties, etc.).
     
  19. ryguy

    ryguy New Member

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    A quote from you not 10 minutes after posting this:

    Boy, that is ultra rich.

    In any case, I sincerely appreciate the help of those who aren't acting like they're experts on every subject in life and never need help with anything.
     
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