Prius 250K miles and replaced hybrid battery

Discussion in 'Gen 2 Prius Technical Discussion' started by 2GenPrius, May 30, 2020.

  1. 2GenPrius

    2GenPrius Junior Member

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    So I yanked out my old 12V battery and turns out its a Toyota TrueStart, has date code 4/14 on it. I think with the 84 month warranty, I should still be good to get a replacement if it does turn out to be bad. I took the battery to 2 Autozones, they both said the voltage tested fine, yet I am worried if there is a weak cell in there. Does Toyota do a very thorough battery test when doing warranty exchanges? I hope so.
     
  2. dolj

    dolj Senior Member

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    The warranty is pro-rated in years 3-7. You need to read the fine print, the warranty is something like if it fails in year 1 or 2 then the battery is replaced n/c. If it fails in years 3 -7 there is a 100% rebate, through to, in year 7, a 20% rebate on the new replacement battery. You are in year 7? 20%?? Anyway, check into what the actual details are.
    Yes, they have a digital battery tester they have to use to provide proof the battery is defective.
     
  3. 2GenPrius

    2GenPrius Junior Member

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    Thanks for the help guys thus far. I wanted to circle back and state that the AGM 12V Truestart battery did indeed test bad at the dealer. Apparently, the dealer cannot warranty service it unless it fails the test (there is a test code generated for corporate to validate against warranty). It did test at 12.5V, yet failed some other portion of the test.

    Interestingly enough, as soon as I put that 12V battery in, a lot of woes that started were gone...up until the mid-range of the hybrid battery started registering overheating again. What's the normal operating temp for the hybrid battery? The fan to cool kicked in like an aircraft was ready to take off. Forward bank registered at 123F, middle was 133.5, rear was 113.4.

    There is definitely still something wrong with the hybrid battery, yet it wont throw a code.
     
  4. ILuvMyPriusToo

    ILuvMyPriusToo Active Member

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  5. SFO

    SFO Senior Member

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  6. 2GenPrius

    2GenPrius Junior Member

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    Thanks. Interestingly enough, I ran across a used hybrid battery pulled from a 2009 wreck with 102K miles. Swapped it in and the car performed beautifully for 2+ hours. Didn't fully assemble everything, but did situate it enough to where the fan/ducts are in place. Interestingly enough, the battery ran cool for the entire time (two times on the freeway, a lot of city driving) without dipping in voltage/amps. The heat did start to increase a tad then started hitting 124 in mid-pack by the time I got home. Not wanting to kill this pack as well, I quickly shut it down.

    I'm thinking it has to be something related to the fan not pulling enough air through the vents or the fan itself is bad, yet not throwing a code. Gonna check for obstruction once the car cools down again. Thanks for the PID info for the torque pro app, that'll help me immensely determine if the fan or its relay is going out.

    Or should I just swap in another fan and run it?
     
  7. SFO

    SFO Senior Member

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    What were the ambient temperatures during the test drive, and are you using the AC to keep the cabin cool (recommended).
     
  8. 2GenPrius

    2GenPrius Junior Member

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    About 109-110 driving around initially. Started to slowly climb to 113-115 only in the middle. I was blasting AC in the cabin at max cold, though as I mentioned, still had most of the side moldings apart other than the ducting for the battery.

    I wish that the battery had a secondary fan on the exhaust to use a push/pull or at least a cross flow setup. No offense to the Toyota engineers yet the complexities of running the fan through all that then out again from the same side of the battery seems inefficient.
     
  9. SFO

    SFO Senior Member

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    Do check for obstructions. With spirited driving, and given those higher outside temperatures, that could be normal for the battery pack. Had the HV battery fan been set at a higher setting (with the AC on), the measured battery temperatures would have been lower for sure.
     
  10. dolj

    dolj Senior Member

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    I don't see anywhere where you have confirmed the HV Battery fan is actually working. You can use your apps to command it to speed 6 (which you will definitely hear), or you can place some tissue streamers near the inlet vent to see if there is airflow. If there is no airflow, check the connector leading to the fan. Having said that there should be a code set when the battery gets too hot from a lack of airflow. In any case, it won't hurt to check.
     
  11. SFO

    SFO Senior Member

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  12. dolj

    dolj Senior Member

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    Thanks, @SFO, so much for my speed-reading "skills". :p:oops:
     
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  13. SFO

    SFO Senior Member

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    Been there done that, and please don't get me started on my big boy depends moments. o_O
     
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  14. AzusaPrius

    AzusaPrius Member

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    Big boy Depend* moments.
     
    #34 AzusaPrius, Jul 13, 2020
    Last edited: Jul 13, 2020
  15. 2GenPrius

    2GenPrius Junior Member

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    [​IMG]

    I know I shouldn't be obsessing over it, yet it seems there has been a few evolutions of Toyota's usage of fans with a hybrid battery pack. Seems there are two from the Prius Plug-In. I know there is a set code for if our 2nd gen runs into issues, but doesn't heat in general kill batteries? Has anyone tried to improve over factory?

    I'm thinking of how to get rid of the heat quick to prolong the life of the battery and also prevent heat soak as the temp climbs. Any feedback would be appreciated.
     
  16. 2GenPrius

    2GenPrius Junior Member

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    Something else just came to mind...resistance generates heat as well...how does the HV battery primarily ground itself? I know there are two leads going away from the battery to the inverter, but where would I check the grounding points on the vehicle frame?
     
  17. 2GenPrius

    2GenPrius Junior Member

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    So I did some digging around and noted that I didn't seat the top duct coming from the blower furthest enough into the battery housing. When I finally did situate it correctly, the temp dropped about another 10 degree F. Wish Dr. Prius had a function built-in as well so I could use that display setup to monitor.

    I use an laser thermometer to determine flow and it seems that the battery exhaust is about 97 F. From my hand I could feel there was some leakage of air so its not a tight system. I'm wondering if its because the foam seal around the ducting is not doing the job, so thinking of going to Home Depot to get some stripping and ensuring a good seal.

    Looking at where the exhaust portion ends up near the 12V battery, is this missing an interface of some sort? Why is there a vent above it?

    IMG_20200712_122812.jpg
     
  18. dolj

    dolj Senior Member

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    Nope, that is the exhaust outlet and it just exhausts into the 12 V battery well and out that vent to the outside world.

    If you look at that spot with the fan running, you should see the airflow move the outlet vent's louvres.

    Your other idea of checking and replacing (if required) the foam seals, is a good idea. There are seals inside the battery too, check them also.
     
  19. 2GenPrius

    2GenPrius Junior Member

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    Good results so far. Going to definitely check those foam seals.

    Screenshot_2020-07-14_194053.jpg
     
  20. 2GenPrius

    2GenPrius Junior Member

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    So I drove it around again today, and the temp in the battery pack rose to about 109F. The ambient was a bit up, 85 in the cabin.

    Its funny, I put everything back together and checked as I did, yet as soon as the coverings went back on its like the hybrid battery doesnt like it. I know that if the blower or relay is bad, it would throw a code. I didn't want to run Torque Pro on fan speed 6 all the time, yet shouldn't the fan kick in before 109?
     
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