Hybrid battery No. 2 Frame wire voltage sensor HACK

Discussion in 'Gen 2 Prius Main Forum' started by Aegean, Dec 21, 2021.

  1. Aegean

    Aegean Active Member

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    I see frequent hybrid battery failures due to P3011-P3024 voltage difference between modules. Is it possible to HACK the system by adding some type of voltage regulator/balancer between the No. 2 frame wire and the battery CPU? This way the CPU will get a similar voltage from all 14 modules using the average voltage value and will not throw codes. Is it going to work?
     
  2. ChapmanF

    ChapmanF Senior Member

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    That seems likely backwards: you see frequent P3011-P3024 voltage difference between modules due to hybrid battery failures.
     
  3. PriusCamper

    PriusCamper Senior Member

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    It's easier to just use Dr. Prius app as you drive to clear codes as they come up... That way you can also monitor battery temp to make sure you don't overheat your pack.
     
  4. Aegean

    Aegean Active Member

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    Temperature control should be covered with the HACK as originally designed with the three thermistors sampling just 3 modules out of 28 and adjusting fan speed. This sampling gave me the following idea for the HACK.

    HACK: We can connect the 14 voltage sensors from the No. 2 frame wire to just 2 blocks instead of 14 blocks. This way the battery CPU will receive identical voltage from 7 blocks at each connection. Even if a cell in a module fails it would not be measured as it will not be connected to a voltage sensor wire. Actually several modules can have voltage difference but as long as they are not in the 2 blocks that are monitored there will be no P3011-P3024 codes.

    For example we can connect wire leads #2, #3, #4, #5, #6, #7 and #8 together at block 4. Similarly, we can connect wire leads #9, #10, #11, #12, #13, #14 and #15 together at block 9. The #1 wire stays as is.

    What do you think of this idea?

    F2D79BB3-4B50-4071-8661-779BBBD4B824.jpeg
     
    #4 Aegean, Dec 22, 2021
    Last edited: Dec 22, 2021
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  5. 2010moneypit?

    2010moneypit? Member

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    Seems unsafe to bypass the safety system. If you have a cell that is very low how do you keep trying to charge it it could overheat.
     
  6. ChapmanF

    ChapmanF Senior Member

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    This seems like another solution to the problem "how do I keep driving on my failed battery until the tops blow off?"

    [​IMG]

    It just seems like one of the more needlessly elaborate solutions to that problem. I think most people who want to do that just keep resetting the codes and driving until the tops blow off.
     
    #6 ChapmanF, Dec 22, 2021
    Last edited: Dec 22, 2021
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  7. mr_guy_mann

    mr_guy_mann Senior Member

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    Why not just fix the actual problem with the car?

    Also, I wouldn't expect it to work as the ecu measures voltage between each of the pairs of wires. 1 to 2, 2 to 3, 3 to 4, etc. Start tying any of the sense wires together and you don't have any voltage difference across them and the ecu will be sad.

    Posted via the PriusChat mobile app.
     
  8. Aegean

    Aegean Active Member

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    You are correct! I just realized the battery CPU does not measure voltage from a single negative post on Block 1 but as you said it measure voltage drop between successive blocks. Maybe there is another way to trick the CPU.

    As far as the need for the hack, I think that the system is very sensitive and throws codes a little early as a warning. I am sure the battery modules could last a few thousand miles more before repair except when there is a burnt cell in one of the modules.
     
  9. Travis Decker

    Travis Decker Active Member

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    Toyota engineers have no idea what they are doing? Just replace the battery if it fails. Not even worth thinking you are smarter than Toyota and “hacking” imho
     
  10. Aegean

    Aegean Active Member

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    Toyota engineers are doing a great job but still many car enthusiasts modifying and improving their cars. If there is the slightest opportunity to optimize battery management why not trying?
     
  11. ChapmanF

    ChapmanF Senior Member

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    Kind of comes down to, what are the odds that corrupting the information the battery ECU relies on to manage the battery ends up optimizing it?
     
  12. rjparker

    rjparker Senior Member

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    There is an opportunity to optimize battery management. You hire a software prodigy, reverse engineer the code in your gen2 and ideally gen3 and gen4, cherry pick the incremental improvements, apply them to reengineered code for your gen2, test and iteratively develop the new code and finally, you have successfully hacked the battery management system.

    Might as well cut to the chase and buy a Rav4 Prime with 300 hp, 42 miles ev and decent mpg. But if you do reverse engineer and improve the Toyota code, a major business opportunity to market the results will appear.
     
  13. mr_guy_mann

    mr_guy_mann Senior Member

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    Toyota engineers were a little "conservative" in their design as they wanted owners to bring a failing battery in to be replaced instead of throwing codes after it had already completely failed.

    Posted via the PriusChat mobile app.
     
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