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Trouble Putting Back Together HV Battery Pack

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Spud Spadoni, Jan 19, 2022.

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  1. Spud Spadoni

    Spud Spadoni Junior Member

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    Hi all,

    This community has been a huge help, as I have learned to do many things on my prius. I am currently reconditioning the battery, went through all the discharge/charge cycles, took the pack apart, took out 6 bad modules and have 6 from ebay to replace. HOWEVER, I am having an extremely difficult time getting the pack back in. It has taking extreme effort to push the modules in and screw them down. I am on the last three modules to go in and for the life of me I can't get them to fit and put the white piece on.

    Any suggestions on putting the pack back together without having to be a body builder?

    Could I try discharging all the batteries? Would that make them even incrementally smaller? I am afraid to do any kind of charge or discharge without the pack strapped in but they only swell on the charges right?

    Any help or advice would be incredibly appreciated.
     
    #1 Spud Spadoni, Jan 19, 2022
    C Wagner likes this.
  2. JC91006

    JC91006 Senior Member

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    Well I hope you have some power tools to help you in assembling and disassembling of the battery case. To do this correctly (and not be hulk)you would need to separate the battery modules from the entire case. Remove the bottom metal case from the modules. To do this, you would need to remove all the 8mm bolts from under the battery pack.

    The easiest way to do this is stand the case up vertically, it will stand securely and will be quite stable. Remove all the 8mm bolts and you can work just with the modules. There are only 4 large bolts holding each side of the modules, loosen up those bolts (I only do one side) and you have easy access to all the modules.
     
    #2 JC91006, Jan 19, 2022
  3. Spud Spadoni

    Spud Spadoni Junior Member

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    Hi JC, Thank you for your response. I have removed all the modules from the pack after doing the reconditioning. The problem is now that I can't get the modules aligned with the 8mm bolts underneath to get all pack reassembled. Any suggestions on reloading and putting the pack back together?
     
    #3 Spud Spadoni, Jan 19, 2022
  4. PriusCamper

    PriusCamper Senior Member

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    As @JC91006 describes above the modules are mounted on the rack first, two white plastic caps and 4 metal rods that hold them together... But I think what you're explaining here is damage to modules. You can only recondition modules when they are bolted together on a rack. If they aren't clamped down the sides of the them will swell and expand when they heat up during charge and discharge. So you probably need to find the swollen ones and replace them. If none of them are swollen and it's just a tight fit, don't worry to much about all 28 bolts under the chassis, as long as you can get most of them. I've worked on packs before that have had warpage in modules from heat damage so I just get rid of the worst ones and clamp it back together, then once the pack heats up enough they tend to straighten out a little under rack pressure and next time I work on pack I'm able to get all 28 bolts in place.

    In general, I remove the pack in its rack from chassis before I do testing and reconditioning because it's easier to keep the pack cool with fans this way.
     
    #4 PriusCamper, Jan 19, 2022
    Last edited: Jan 20, 2022
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  5. Spud Spadoni

    Spud Spadoni Junior Member

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    Hi Camper,

    Thank you for your response, I did leave them bolted while reconditioning and before removing any modules. I think like you mentioned, it was just a really tight fit. I gave up getting all the bolts into the modules and was able to get the white piece and bolts back onto the end. Although I didn't get the last 4 modules screwed into the bottom, I don't see them ever shifting it was so tight. I am about to start cycling the 6 modules I got off ebay. Fingers crossed they are solid and similar to the capacity I have with my original modules. I would absolutely dread taking it apart again right now. Thanks again :)
    Spud
     
    #5 Spud Spadoni, Jan 19, 2022
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  6. alftoy

    alftoy Senior Member

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    This video has tips on reassembling HV battery, at about the 17-21 minute mark. Standing on end helps as well.

     
    #6 alftoy, Jan 20, 2022
    Last edited: Jan 20, 2022
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  7. C Wagner

    C Wagner Member

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    Great video for the OP’s issue as well as his to balance. Note: I used thick solder for the long wire on plus and minus and DONT use an impact or even power drill to tighten busbar bolts!!!
     
    #7 C Wagner, Apr 2, 2022
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