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New OEM hv battery post stud snapped

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by jgcannon2, Jan 1, 2021.

  1. jgcannon2

    jgcannon2 New Member

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    Newby here, 1st post

    I have a 2008 Prius that was showing codes for bad modules, so I decided to buy a new OEM traction battery and just replace it.

    I was assembling old parts to new parts and had new cables to attach. As I went to tighten down the 8 mm bolts to the battery modules to 60 inch pounds, I snapped 2 of the posts off!

    What's my next best course of action?

    My reading here says that I've destroyed these two modules and need to replace them. Am I likely to be able to talk the dealership into selling me two new replacements? How might that conversation go?

    Or, how do I find essentially brand new unused modules that I can buy to replace them? (The old modules have some ridges in the plastic next to the vent ports, while the new batteries do not have ridges there.)

    And, I guess the warranty's shot after this.

    I guess, as a stop gap, I could pull two of the old modules and put them in with the whole new battery pack just to get it to run. But, I'm guessing that may not be advised given the age and usage difference between old and new?
     
    #1 jgcannon2, Jan 1, 2021
    Last edited: Jan 1, 2021
  2. JC91006

    JC91006 Senior Member

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    You cannot buy 2 new modules, you would have to return the battery for another one. I think an understanding person at the Toyota parts counter will be able to exchange that for you. If the person is an older person at the parts counter, tell them you ate some spinach right before torqueing the bolts (hopefully they get the joke)

    No you do not want to mix 26 brand new modules with 2 used modules, that's just asking for trouble.
     
  3. 2k1Toaster

    2k1Toaster Brand New Prius Batteries

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    60-in-lbs is the wrong value.

    You cannot buy 2 new modules. The whole problem I solved was because Toyota does not sell new modules individually.

    You may be able to lie your way into a new battery with the dealership, but really since you broke it they don't have to give it to you.

    As a stop-gap you can use some used modules, but now you have a used pack. You're going to be playing whack-a-mole from the beginning which offsets the reason to buy a new pack in the beginning.

    Your second best option may be to buy a couple Yabo modules. They are form-factor compliant to the PrimeEarth's but they are crap. They're better than any used module you can buy, you should be able to get 4-5 years out of it.
     
  4. PriusCamper

    PriusCamper Senior Member

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    This makes no sense because a brand new pack comes with new bus bars and wire frame already bolted to the modules? Why would you replace brand new with your old used ones? Or maybe you're referring to the bolts where the module mounts to the chassis? but again that all comes pre-mounted?

    If your efforts to get a new pack with the dealership fail, which seems likely, I'd recommend you find someone with a drill press/machine shop and drill a small hole in the terminal posts and reattach the snapped off posts with a small screw and a bit of solder...
     
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  5. ChapmanF

    ChapmanF Senior Member

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    Can you say more about where you got this 60 in-lb figure? It's the wrong figure, which is why they snapped, but if you found it in some source that others might stumble into and rely on, maybe identifying it here will save someone else the same grief.

    It could also be worth mentioning that when we talk about the size of a bolt, stud, or nut, we give the diameter of the threaded portion, not the size across the hex head or nut or the socket size you would use to turn it. If you would use an 8 mm socket to turn some bolt or nut, one thing you know for sure is that is not an 8 mm bolt or nut.
     
  6. SFO

    SFO Senior Member

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    If the two (2) brand new modules aren't saveable, then reach out to @TMR-JWAP and ask for 'newish' pair to them replace with.
     
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  7. jgcannon2

    jgcannon2 New Member

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    I was afraid that the answer was going to be "No, you can't buy 2 new modules". Still, you give me some hope that I may be able to get a replacement at the counter, so it's worth asking anyway. Thank you.

    Yep, 100% my own fault, so no room to demand anything.

    Nice to hear your solution may bypass that shortcoming of Toyota's policy.

    I had seen a YouTube replacement where they quoted 60-in-lbs for the buss bar nuts. Looked more later for other sources and saw 50-in-lbs for the 2 studs where the orange interlock attaches. But yet another diagram showed 48, so I don't know which is correct? Can you clarify for me?

    Thanks for the recommendation on the Yabo cells as an option. Are there any sources you can recommend?

    Thanks for your reply.

    Actually, with the new replacement packs, you get the tray of modules without the head sub tray that holds the ECU that you have to transfer. Then they include new cables to attach, 2 connections on one side where you attach the cable to the orange safety interconnect, and 2 on the other side to attach the + and - lines that connect to the cars orange cables, so, 4 nuts the installer must attach. All the rest are pre assembled, as you described.

    I have a drill press and wondered about the drilling out option. Wasn't sure if standard rosin-core solder could handle the current and temperature? And concerned about how much depth there is to work with.

    Thanks for weighing in.

    Don't laugh, but from the ChrisFix YouTube replacement video and his attached PDF.

    Interesting point on the size nomenclature. I think in the video, for car disassembly, he was referring to nuts by the driver size needed for attachment, so I was quoting that. Certainly is not an 8 mm post, but that was the socket size needed.

    Great to have multiple suggestions for back-up options. Thank you!
     
    #7 jgcannon2, Jan 2, 2021
    Last edited by a moderator: Jan 2, 2021
  8. jgcannon2

    jgcannon2 New Member

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    It was a new torque wrench l never used before. Just picked it up to have something light enough for this use. Could be operator error, but on repeat reading, I was following directions. Thought I should test it out a bit on some non critical use before using it for the battery again. Maybe I'll compare with another ft lb unit to see that it's working right. Thanks for relating your experience and providing values.

    Thanks, too, for your offer for potential replacement modules. Let me consider all this advice, and I'll get back to you either way.

    Thank you one and all for the input!
     
  9. TMR-JWAP

    TMR-JWAP Senior Member

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    Couple things here.
    1. You need to check whatever tool you were using for torqueing. There's no way a true 60 inch pounds (5 ft-lb) should snap one of these studs. I've tested them at their weakest condition (with no cable or busbar attached), and it took ~110 in-lb to cause damage. The torque spec is 48 inch pounds (4 ft-lb) but I use 60 quite frequently and have never had a problem. I've seen several youtube videos that discuss using 60 also.
    2. If you need a couple modules that near the capacity of a new module, I can help you out. A new module is rated at 6500 mah, but usually tests in the 6900-7200 range or better, when new (using my methodology). Using the same exact methodology as I used for testing new modules, I have many modules that test to a similar range and should be effectively indistinguishable during operation.
     
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  10. TMR-JWAP

    TMR-JWAP Senior Member

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    I have a drill press and wondered about the drilling out option. Wasn't sure if standard rosin-core solder could handle the current and temperature? And concerned about how much depth there is to work with.

    Please don't do this. It's a catastrophe waiting to happen. I have a Gen2 battery where the original owner accidently broke several studs using a ft-lb torque wrench instead of an inch pound while attempting a DIY rebuild. Mistakes happen. The problem was multiplied when they attempted to drill all those broken terminals so they could just screw into it to mount the busbars. It doesn't work and makes a holy mess of everything. It effectively turned that entire battery into scrap.
     
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  11. Mendel Leisk

    Mendel Leisk Senior Member

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    Any chance you did foot pounds??
     
  12. edthefox5

    edthefox5 Senior Member

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    Whenever I use T wrench I always check it out on a tire lug nut which can handle lot of torque. It’s a wrench most people don’t use often easy to set it up wrong.
    Some t wrench’s click when torque reached some like my craftsman just do a subtle release feel have to pay attention.
    On this battery I would not use a bigger socket wrench than a 1/4 inch.

    I always thought a factory Toyota battery came with all the battery’s installed and assembled already.
    What new battery did you buy and where and how much please.?
     
  13. Mendel Leisk

    Mendel Leisk Senior Member

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    You can also get T-handle wrenches, preset to low torque values. I think they just slip once torque is achieved?
     
  14. ChapmanF

    ChapmanF Senior Member

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    Don't worry, I'm not laughing, just trying to help figure out where incorrect information is being found so we can make it easier to avoid.

    It's an easy mistake to make, but it can have disastrous consequences if somebody uses that size to search in a generic table of torque limits by size.

    The most important point there is that, yes, the torque spec is 48 inch pounds, from the Prius repair manual:

    studs.png

    The fact that there might be "several youtube videos" (or their attached PDFs) that give different information is a powerful reminder of why important things should be looked up in the manual.

    If the nut size fits an 8 mm socket, then the stud is an M5. If you go looking for M5 in just a generic table of torques for graded steel fasteners:

    trqs.png

    you would find that for a class 5.6 stud you wouldn't go over 1.99 foot pounds (less than 24 in lb), and even for a class 8.8 you wouldn't guess more than 4.54 ft lb (less than 55 in lb). I copied the untreated/black section of the table; the torques in the zinc plated section are slightly lower.

    Of course generic tables like that are published for steel fasteners that are strength-graded and meant for structural assembly. The studs on a battery module are going to be made of some material chosen for its electrical properties more than its structural strength, and there aren't likely to be generic tables showing their torque limits. That's the kind of situation where it's critical to use the information from the manufacturer about the intended torque. Specified torques are a bit conservative, of course, to have a safety margin. One might have used a higher torque "quite frequently" and even gotten away with it, but that isn't a good reason to make new readers sort through conflicting information about what the specified torque is.
     
    #14 ChapmanF, Jan 3, 2021
    Last edited: Jan 3, 2021
  15. jgcannon2

    jgcannon2 New Member

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    Appreciate your advice on this. I was picturing trying to use a tap and die set and just drilling right through everything...
     
  16. jgcannon2

    jgcannon2 New Member

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    I'm sure. I have a 1/2" and a 3/8" in ft lbs and picked up this 1/4" in in-lbs just to prevent that mistake. Good suggestion, thanks.
     
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  17. jgcannon2

    jgcannon2 New Member

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    I wish I'd thought of that, trying it out on something first where I couldn't do damage. Thanks for the suggestion, and I will next time! Yes, this is a quarter inch in in-lbs.

    Right, as I replied to someone above, the new factory packshave everything put together except for four bolts for attaching new cables.

    Was from my local Toyota dealership for $1,655.


     
  18. donbright

    donbright Active Member

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    Ah yes. Perhaps you mean the infamous "I bought the most hated car on the internet and made $1000.00" with over 6 million views now. He takes a bunch of used modules, calls them "rebuilt", claims he was told they will last 6 years, promotes the "rebuilder" company, and links to the installation document provided by that company, which lists 60 inch-pounds as the torque spec.
     
    #18 donbright, Jan 3, 2021
    Last edited: Jan 3, 2021
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  19. jgcannon2

    jgcannon2 New Member

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    I appreciate the explanation, and I'm learning a lot. Thank you. Yeah, I was just following a youtube, and didn't even think to look in the manual. Expensive lesson, this one!

    Didn't know that, thanks. If the one I'm using is defective, I may need to get one of those.

    Yep, bingo! That's the one!
     
    #19 jgcannon2, Jan 3, 2021
    Last edited by a moderator: Jan 3, 2021
  20. Mendel Leisk

    Mendel Leisk Senior Member

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    Considering the costs and ramifications, maybe these rebuild kits should come with a t-handle 48 inch/pound torque driver, the kind that slip when they reach target torque. They likely wholesale for something like $15. Or at least have them on offer, part of an install kit.
     
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