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Torque OBD reader shows HV battery charging at 14kw

Discussion in 'Gen 2 Prius Main Forum' started by BrokenWrench, Oct 23, 2019.

  1. SFO

    SFO Senior Member

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  2. BrokenWrench

    BrokenWrench Junior Member

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    Good News my HV leak appears to be one or more of the HV battery cells. I did the test as StrawBrad outlined via video and my meter shows just over 115 volts and does not bleed down.

    I suppose the thing to do is buy a couple of cells before pulling the battery. I pulled the battery about 18 months ago just to clean all the post and take a look. At that time all the cells test about 8 volts each.
     
  3. BrokenWrench

    BrokenWrench Junior Member

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    After clearing the codes I could not get the car to repeat the POAA6 code but did the test again and it showed there is a HV leak. Thus, I pulled the battery and removed the nuts that connect all the cells together and tested each cell and a found five that had showed small leaks. With my volt meter set to 20volts dc my 5 seeming leaking cells showed .24v, .14v, .03v, .28v, and -.01V (that negative reading surprised me and I did not have the terminals reversed)

    I also did the above test with all the cells still connected and the results were a bit different and I can see how that would be possible so I ran the test with the cells separated and got what I think is a more accurate test.

    Any thoughts? Is it worth replacing the individual cells or is it really new battery time. The car has 235,000 miles and has some minor body damage, the transmission makes a little bit of a howl at 75 MPH and above so it's probably not worth putting a lot of money into it.

    .........maybe some good used cells are the way to go and keep it within AAA's 200 mile towing distance or use as my back-up plan car : )
     
  4. strawbrad

    strawbrad http://minnesotahybridbatteries.com

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    That shows that your leak is 115 volts from the negative side of the pack. Gen 2 modules leak from small cracks next to the mounting bolts. The hairline cracks form inside the rectangular recesses next to the mounting bolts. They are too small to see. Leaking modules will also leave stains on the case bottom.

    Check for voltage between each module terminal, both positive and negative, and a good ground on the case bottom. Leakers should measure close to full module voltage. The leak is opposite the terminal that shows voltage.

    This module was charged enough to create a little pressure. A little soapy water shows the source of the leak.

    132999_leak.jpg
     
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  5. BrokenWrench

    BrokenWrench Junior Member

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    20191121_142333.jpg 20191121_181026.jpg 20191121_181309.jpg 20191121_221516.jpg


    With the bus bar removed and re-testing for leaks the only leak I can find is the one cell farthest from the computer side and it shows only .01 which might not really be a leak. All others are read "0" leak.

    I am wondering if the dirty bus bar contacts created the leak?

    20191121_142333.jpg 20191121_181026.jpg 20191121_181309.jpg 20191121_221516.jpg
     
  6. BrokenWrench

    BrokenWrench Junior Member

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    Any thoughts on the dirty bus bar.
     
  7. strawbrad

    strawbrad http://minnesotahybridbatteries.com

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    Dirty bus bars do not cause a leak.

    The sixth module from the right has a stain under it. That's a prime suspect. How does the other side look?
     
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  8. BrokenWrench

    BrokenWrench Junior Member

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    Yep, if I press down on the cell I get an intermittent reading and 3 others down on that end of the battery as well.

    (Now whoever heard of an intermittent electric issue : )

    I think my next move it to pull the cells and inspect. Thanks again!
     
  9. BrokenWrench

    BrokenWrench Junior Member

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    BTW, the stain on #6 does not show on the other side but I think you are correct and when I pull the cells it will show.
     
  10. strawbrad

    strawbrad http://minnesotahybridbatteries.com

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    The adjoining modules could just have been leaked upon by #6 and be fine.
     
  11. PriusCamper

    PriusCamper Senior Member

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    When you say: "cell farthest from the computer side and it shows only .01"
    what do you mean by that when your voltage numbers for that module #28 looks normal?

    Also are these voltage numbers from a self-discharge test or a load test? They all appear to be relatively normal and when you're using a free harbor freight multi-tester, I'd be more willing to blame that then your pack.

    Lastly, it looks like the bus bars were at some point treated chemically in a way that converted the corrosion into some kind of black laminate? Did you do that treatment or is this evidence that previous owner had work done on the pack?

    As for bus bar cleaning you can either put them in a rock tumbler for a few days, or you can buy brand new solid nickle bus bars at https://www.reflexconcepts.com/ Or a new wire frame no. 2 for $50 from Toyota will replace one side of your bus bars, as well as replace the voltage sensor wires. Corrosion tends to travel up those wires into the ECU so check that plug for signs of corrosion.
     
  12. PriusCamper

    PriusCamper Senior Member

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    Duplicate post deleted...
     
    #32 PriusCamper, Nov 22, 2019
    Last edited: Nov 22, 2019
  13. dolj

    dolj Senior Member

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    This statement (correct me if I'm wrong) leads me to believe you think the P0AA6 is talking about voltage leaking from a module–in your case being 0.01 V down. Voltage is involved, but it really is talking about physical electrolyte escaping from a module and dripping down to the case, whereby it creates an unintended current path. (This is why strawbrad said to look for staining–the electrolyte stains the case.) This unintended current path creates the voltage leak. So, modules physically leaking are what you should be looking for. Look hard, because the electrolyte is nearly invisible. Once you have found and replaced your leaking modules, you need to remove the modules from the case and clean the modules and the case thoroughly to remove any trace of electrolyte.
    I would do this anyway as a matter of course.
     
    #33 dolj, Nov 22, 2019
    Last edited: Nov 22, 2019
  14. PriusCamper

    PriusCamper Senior Member

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    Yeah I was thinking there seems to be some communication confusion related to voltage leaks vs. electrolyte leaks. Most electrolyte leaks aren't going to have noticeable difference in voltage compared to modules that aren't leaking. Spraying everything down with vinegar and looking for fiizzing or changes in color can help sometimes...

    Lastly, the proper rebuilding of a battery pack is not based on finding leaks which is similar, but not the primary focus. The focus is based on the concept of finding the bad cell that caused the pack to fail. There are 6 cells in a module and in most cases 28 modules in a pack and because it's wired up in a series rather than in parallel, that means if just one of the 168 cells in your pack fails, the whole pack fails and you will have to replace and match at least one module / 6 cells to the existing pack.
     
  15. BrokenWrench

    BrokenWrench Junior Member

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    Yes, electrolyte escaping and causing a voltage path from individual cells. I was finding a path on 5 modules with the HF meter....I suppose its possible that some of the modules may be contaminated by the module next to it as StrawBrad said may be possible.

    My current plan is to replace the 5 modules.

    battery box .jpg
     
  16. strawbrad

    strawbrad http://minnesotahybridbatteries.com

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    Are you reading close to full module voltage? That's a leak. .1 or .01 volts is not a concern.

    It's okay to wash the modules with soap and water. Don't leave them submerged.
     
  17. BrokenWrench

    BrokenWrench Junior Member

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    deleted double post
     
  18. BrokenWrench

    BrokenWrench Junior Member

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    None of them were leaking near full voltage and .28 volts was the highest voltage shown on my meter set to 20v DC. (I checked with a 2nd meter to confirm)

    Yet, the stains are on the base of the battery box and the code did throw.

    It would not surprise me that if I replaced the one cell, cleaned the others - painted the stained areas with rustoleum and bolted it all back together ..... perhaps the issue would be fixed. (I don't know that I'll do it that way but that would not surprise me)

    I'm wondering if I put a 12v trickle charger on the modules and did a soapy water test ... perhaps this would show any leaks. I could probably rig a lower voltage charge if the the 12v at about 2 amps is any cause for concern.

    I get back on it after thanksgiving : )
     
  19. PriusCamper

    PriusCamper Senior Member

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    are all the serial numbers on your modules the same? If they are not it could mean that the leak stains on the chassis were from already replaced modules...
     
  20. dolj

    dolj Senior Member

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    If they were original modules, they wouldn't have the same serial number. They would be sequential with the last few digits incrementing.
     
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