One last HV battery question before I let my Prius die....

Discussion in 'Gen 2 Prius Technical Discussion' started by Kactus, Oct 16, 2021.

  1. Kactus

    Kactus Junior Member

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    I'm finally ready to let my Gen2 move on to the Great Hybridyard in the Sky due to modules going bad whack-a-mole style on me. I was warned about this by my Prius mentor (hey eric!) but it's became more about the challenge / curiosity for me than saving a Prius w/ 210k miles on it. I'm less annoyed at giving up on my Prius than just knowing what's going on. I guess at the moment of death we all look for answers.

    My question: is there another component that could be causing strong, load-tested modules to suddenly go bad? Or are old HV packs inherently unstable which can cause any mod to go bad suddenly?

    (*Note** 12 months ago I'd previously and successfully replaced a bad mod so I know how to do a mod replacement.)

    Background:

    So...

    - few months ago I got red warning (!)
    - opened up pack - did stress test on each module
    - results showed that 4 modules were bad: #6, #10, #12, #15. (see attached chart)
    - found 4 replacement cells with good charge. did stress test on each and results were good.
    - swapped bad mods with good mods
    - charged all mods to 7.8v
    - reinstalled pack. no red warning light. drove for 10 mins and got the warning light.
    - did a Carista check and it came back w error codes: P3019 & P3023
    - checked my previous load test and those blocks (#9 & #13) seemed fine?

    Any final words of insight or wisdom would be greatly appreciated!
     

    Attached Files:

  2. Aegean

    Aegean Active Member

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    Excellent work with the 2 min load test. However, you might need to also do the 3-5 times charge/discharge cycle to identify modules with low capacity. There are some more things like balancing etc. Probably you have seen here posts like the one below:
    Prius High Voltage Battery Reconditioning | PriusChat
     
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  3. Kactus

    Kactus Junior Member

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    thanks for that. I hadn't seen that post. there is part of me that wants to scratch that itch but another that says, say goodbye to a great car and move on ;)

    I guess in my case, even though I did a stress test, I wasn't getting a true reading of which mods were bad.
     
  4. TMR-JWAP

    TMR-JWAP Senior Member

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  5. Another

    Another Active Member

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    Maybe just sell it to someone who wants to spend time fixing it.
     
  6. Aegean

    Aegean Active Member

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    Maybe it is a good idea to fix the car and keep it. Here, the resale value is around $3300 and not ready for scrap yet. Note that used car prices went up by 25% due to supply chain issues. A used Prius will continue to be more valuable than other used cars as gas prices remain high.

    Now back to the hybrid battery. You have completed step 1 to check for lower module voltage by about 1.2v and identify a bad module with a single burn cell. You have completed step 2 to load test each battery module and identify modules that can not hold charge like the rest. You can do step 3 using hobby chargers to charge discharge the modules 3-5 times and identify modules that have low capacity. And step 4 to do the same for the replacement modules. Last step is to get each module at identical voltage with the rest and connect in parallel and let all modules equalize for a day before you do final connections and install it.

    Even if all the steps are completed correctly, the battery package is still 17 years old. The possibility of another module failing in the next 2 months or 2 years is now rather high. Another more costly approach is to buy an OEM Toyota battery G951047031 for around $1550-$1700 depending on dealer discount and install it DIY but this option makes sense only if you plan to keep the car more than 4-5 years.
     
  7. mr_guy_mann

    mr_guy_mann Senior Member

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    Even if you have all "good" modules, that doesn't mean that they all have the same capacity anymore. I did LOTS of reading here on the forums when I bought my Gen2 with a failed HV battery. Ended up getting 4 hobby chargers and 5 ebay modules. Took about 5 weeks here and there to cycle all the modules (3-6 times each) until all measured 5500-6000 mAh.

    Knock on wood, still working well (0.2-.3V difference) after 17k. When it goes, I'll probably get a new pack.

    Posted via the PriusChat mobile app.
     
  8. Kactus

    Kactus Junior Member

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  9. Kactus

    Kactus Junior Member

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    A very astute analysis. Even if I could tame the pack with further steps...another module could go in months and it's back to the same problem....

    Have been factoring in the supply chain issues as well so leaning towards a new OEM pack. Does one buy these directly - and only - from a dealership? Do I buy only the 28 modules or does it come with a new ECU etc? Any other tips on buying an OEM pack?

    Thanks in advance!
     
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  10. bisco

    bisco cookie crumbler

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    there are many threads here on pack replacement. you can shop around for an oem, as far as you are willing to drive, and compare to the new modules from 'newpriusbatteries' and dr. prius lithium modules.

    on the oem, you do swap a lot of stuff over.
     
  11. Aegean

    Aegean Active Member

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    Nothing like the tested OEM battery. I see one dealer in your area selling for around $1699. You need to check different dealer prices with
    Toyota Parts and Accessories - Official Online Store


    https://parts.tustintoyota.com/productdetails.aspx?makeName=toyota&modelYear=2004&modelName=prius-hatchback&stockNumber=g951047031&ukey_product=63533084&referer=parts.toyota.com&machineIDT1=l43tbi0jsb45kdz1dtr4qqxu

    I asked my local dealer last week and he said there is absolutely no issue selling me the OEM hybrid battery as retail. The price was $1535 online. Note that they need to keep a core deposit which eventually would be returned.
     
  12. MikeSF

    MikeSF Member

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    Man I wish I could get that price here, if I drive 75 miles I can find it for $1699, if I drive 30 miles and cross 1 toll bridge $1755, or any actual local store (<20 minutes) full MSRP at $1950 :(
     
  13. Another

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    Is 75 miles too far to drive?
     
  14. Mendel Leisk

    Mendel Leisk Sand Pounder

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    Good question.

    Up here, just north of the 49th parallel, there's "post box" services, in small towns just south of the border. Sometimes US retailers flat-out won't ship to Canada, or if they do it's with onerous shipping charges. So these post box services have a viable business model: if you're prepared to drive down (to Blaine in my case), and contend with possible duty charges at the border as well. I think with the latter you get waved through as often as not.
     
  15. Another

    Another Active Member

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    75 miles from SF doesn’t sound like a trip to the moon to me. In a Prius that’s 3 gallons of gasoline round trip. Even in California that’s only $15.
     
  16. rjparker

    rjparker Senior Member

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    Old is old. Getting it to run again with a better used module just means you have another mix of used modules which do have an end of life close to each other.

    My understanding is you move some of your electronics to the new assy.
     
  17. Tombukt2

    Tombukt2 Member

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    I just bought an OEM pack just beware for the 1699 you are only getting the battery rack and cover the front end of the battery with the computer and whatnot is not there you have to keep your old one I had to take mine off at the dealer because they swore up and down the battery was complete if I can attach the pictures I will so at the dealer I took the front end of my battery off which houses the connection to the car the relays the battery computer and I think that's about it the new battery comes with the harness that goes to the plug or goes to the fuse and shut off the big orange plug all the other wiring is already on the battery you're only going to apply the plug harness for the removal of the battery I hope the pictures will post

    SM-A715F ?
     
  18. Tombukt2

    Tombukt2 Member

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    Duh the photo. Luckily the parts guy at this dealership was very unknowledgeable I basically took a whole bunch of parts off the battery He didn't care do whatever and so I did 20211104_154612.jpg

    SM-A715F ?
     
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  19. Aegean

    Aegean Active Member

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    Congratulations! Excellent choice and price.

    Please let us know what exactly needed from the old battery when you install it. Based on your description and photo I assume we will need to transfer:
    1. Upper battery carrier (computer case)
    2. Battery ECU
    3. No 1, 2 and 3 system main relays and wiring
    4. Main resistor
    5. Current sensor
    6. Orange plug ( service plug with orange wires is from new battery)
    7. Plastic terminal covers
    8. Junction terminal
    9. Mounting screws and nuts
    Is anything else needed?
     
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