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Is there a way to test HV Battery ECU?

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Tan_Prius_2007, May 16, 2016.

  1. Tan_Prius_2007

    Tan_Prius_2007 Junior Member

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    I've pulled the HV battery from my 2007 Prius with 144, 000 miles given recent Red Triangle of Death (P0A80) and looking to replace battery pack but want to rule out the ECU. I've searched the threads and found mention of testing the ECU but wasn't clear.

    Does anyone know how to test the HV Battery ECU in or out of the car? Using a volt meter and light bulb, etc......I would really like to rule out the ECU before putting $600-$800 dollars in a rebuilt battery pack.
     
  2. S Keith

    S Keith Senior Member

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    It's not the ECU. You would have received a different code.

    ECUs fail very rarely, and when they do, fire is typically involved (search this site). HV batteries fail all the time in comparison. Under magnification, carefully inspect.the ECU pins and the voltage sensing harness (orange connectors) for indications of corrosion. The presence of corrosion indicates a potential for subsequent failure.

    Did you find a significant voltage disparity when you opened the pack?

    Typically the 2 end modules will be 0.05 - 0.20V lower than the middle 26. The middle 26 are typically within .05V or less. Anything outside that range is likely confirmation of the P0A80.

    You can also reinstall the battery and conduct the discharge test in my signature and confirm the reduced capacity.

    Lastly, severe corrosion of the bus bars AND sensing wires can lead to bad input that can trigger a code. Doesn't happen often, but it can.

    Steve
     
    #2 S Keith, May 16, 2016
    Last edited: May 16, 2016
  3. Tan_Prius_2007

    Tan_Prius_2007 Junior Member

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    Ok I do have some light corrosion, I'm attaching photos. I'm also including the voltage reading, taken about 2-3 hours after disconnecting and removal of the HV Battery. Just FYI, my wife and kids have complained since I bought the 2007 Prius/80k miles, 3 years ago, that it smelt like a barnyard in the cabin of the car. I noticed the smell on the test drive and mentioned it to the previous owner who claimed that his wife bordered a horse and used the Prius to take trips to take care of the horse.....hind sight, that may have been BS to cover problem with batteries....but have had no problems for past three years.
     

    Attached Files:

  4. S Keith

    S Keith Senior Member

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    IMHO, the smell of a battery is not "barnyard" in nature. It is specific. Having smelled several, it's subtle and consistent.

    I suspect your odor issues are more related to fecal matter on the previous driver's boot/clothes. :)

    Your voltages are a little messy. 7.63 - 7.75, and they don't follow the typical spread. Were they taken after the bus bars were removed? If not, I recommend you re-measure directly on the terminals.

    Look at the back side of the bus bars. The copper "circle" that contacts the terminal should be relatively clean even if the surrounding area is heavily corroded.

    At a minimum, you need to completely clean your bus bars and sensing wires.

    You might want to consider the Hybrid Automotive Prolong reconditioning system instead of replacement; however, without a discharge test confirming consistent in-car voltage response, I can't be certain.
     
  5. Tan_Prius_2007

    Tan_Prius_2007 Junior Member

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    The copper connections appear to be clean on the bus bar for the battery side, with corrosion around the outside circle. The voltage readings were taken with bus bars removed. I will put the battery back together install in car for discharge test and report back.

    Thanks Keith!

    If I may go off topic for a second. I'm a newbie and have a couple questions.

    1) What is Forced Charge?
    2) What does 'placing the car in Lock mode' when parking in driveway/garage?
    3) Since I have the battery pack out of the car, should I shuffle outside batteries to inside, and inside batteries to the outside, keeping paired batteries together?

    Thx again!
     
  6. S Keith

    S Keith Senior Member

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    1) as described in the test; Ready mode, in "D", parking brake set, foot brake firmly pressed, full throttle to charge until it stops charging as described.
    2) Not sure.
    3) Not really. Capacity distribution in the middle 20 modules is pretty random. IF you knew the individual capacities of your modules, then yes, populating strongest in the center and getting weaker outwards is good practice. If you don't know the capacities, it's a crap shoot. Might make it better or worse.
     
  7. S Keith

    S Keith Senior Member

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    I didn't see that you mentioned it, but you have to remove the ECU to inspect the pins in the orange connector. Best results or had when you use 10x magnification
     
  8. Tan_Prius_2007

    Tan_Prius_2007 Junior Member

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    Ok, I cleaned the copper connections on the HV battery modules, re-installed the HV battery and followed your directions on the Forced Charge (thanks by the way, worked well!) and watching the voltage drop under Load (AC, rear defroster and headlights while in Drive) I discovered 'HV Block5' dropped faster than the remaining modules. All remaining modules dropped in unison.

    I performed the Forced Charge and Discharge twice, and both times 'HV Block5' dropped below the remaining HV Blocks. I've attached images below.

    Question: Could I extend the life on my HV Battery Pack by buying two matching modules to replace HV Block5..?


    IMG_0323.PNG

    IMG_0324.PNG IMG_0326.PNG
     
  9. Tan_Prius_2007

    Tan_Prius_2007 Junior Member

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    I have not inspected the ECU yet, was wanting to perform the Forced Charge/Discharge first.
     
  10. JC91006

    JC91006 Senior Member

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    Forget checking ecu, block 5 is the problem

    SM-N900P ?
     
  11. S Keith

    S Keith Senior Member

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    Yes (sorta).

    The good module in block 5 is probably fine as it was "protected" by the failing module; however, there seems to be a preference for replacing pairs. This is likely due to the assumption that a presumed good pair from another pack will be well matched to one another. This is just playing the odds that a pair will better match each other than a single module with the block's good module.

    It's totally chance. If you actually recondition/rebalance, then yes, you have a very good chance of significantly extending the life of your pack. If you just swap in a replacement single or pair, it's a total unknown.
     
  12. JC91006

    JC91006 Senior Member

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    I'm quite surprised at the resting voltage of block 5, wouldn't even know a problem existed. I guess if you let it sit a week, the true colors would show

    SM-N900P ?
     
  13. S Keith

    S Keith Senior Member

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    This is true in some cases where one or more cells have excessive self-discharge; however, it can just be a symptom of a very weak cell compared to the rest. I have a module that is only 2700mAh capacity and will hold boss voltage for months. If I run the discharge down to 5.4V, the capacity approaches 4000mAh indicating the other 5 cells are carrying the weak one.
     
  14. dolj

    dolj Senior Member

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    You probably will get more benefit at this point by using the HA grid charger, as mentioned by S Keith previously (Post #4) before tearing your pack down and doing any replacements.
    You've done at test now and got some metrics.
    As it is all easily accessible at present, it would still be a good thing to do, even if just for the sake of thoroughness. In any case you cannot categorically make the statement above, it may be a factor. It is not necessarily the factor.
    And as an aside JC, can you seriously not change that default sig to say something like "Posted from my SM-N900P" or just blank it out? And why the question mark at the end? Is it not sure what it is? It causes so many noobs unnecessary confusion.
     
  15. JC91006

    JC91006 Senior Member

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    Using quick reply in tapa talk, that sm-n900p comes up automatically, only way that I'm able to turn it off is doing non quick replies.

    I'll have to look into it some more

    SM-N900P ?
     
  16. JC91006

    JC91006 Senior Member

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  17. Tan_Prius_2007

    Tan_Prius_2007 Junior Member

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    Any recommendations for on-line websites for module replacements? In searching the PC threads I found the following site HAC V4.0 for $49 each. I'm also looking at HV charging/re-conditioning system given my wife also drives a 2010 Prius, I personally would like to get 2-3 more years out of my 2007 HV Battery.

    Thanks to all for assistance and advice, I will be ordering a replacement module this week and report back on status.
     
  18. S Keith

    S Keith Senior Member

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    Most get them from eBay. Total chance.

    You need clarification on what's warranted. They need to guarantee CAPACITY, not voltage. If they're just giving a "voltage" warranty, it's a shot in the dark just like eBay, and the wording concerning their "testing" sounds like it's voltage based.
     
  19. ericbecky

    ericbecky Hybrid Battery Hero

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    I almost always sell modules in pairs.
    Because the reality is if you have one bad module now, you will have more in the future.
    This way you have a spare and you limit the amount of variables as you replace module in the future.
     
  20. Berch1943

    Berch1943 Member

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    I noticed the main question of this topic still hasn't been answered.
    The discussion has quickly shifted into battery modules. I had the same question too, so it may be helpful for others in the future.
     
    rrcharti likes this.