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4 temperature sensors in my gen. 2 battery pack not 3

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by bmparent, Jun 12, 2019.

  1. bmparent

    bmparent Member

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    So I'm trying to put my battery back together and seeing that my pack has 4 temperature sensors, 3 wired from the bottom, 1 from the top. I'm clear that I have to re-clip the sensors onto the new modules but according to the manual I'm using there should only be 3. The 3 wired to the bottom area of the ECU were clipped to the bottom of the old modules, and the 4th one, the one wired to the top, was clipped onto on of the bars that runs a long the length of the battery, connecting the compression plates. I suppose I could just try to arrange things so that it's in the same place when I put the battery back together, but I was planning to clip the bottom-wired 3 sensors to the top of the new modules (as the manual recommends) so I don't know if a 4th would be redundant on top or maybe it's better somehow clipped to the bottom of the modules.
     
    #1 bmparent, Jun 12, 2019
  2. TMR-JWAP

    TMR-JWAP Senior Member

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    The one on top is NOT a module temp sensor, it is intake air temp. Please put them all back where you found them or you're going to cause yourself a whole host of problems.

    And what manual are you using? The author of that manual apparently has a serious misunderstanding of why they are where they are.

    One issue....The ecu is looking for an approximate temperature difference between inlet air and exit.
    another issue....Putting the module sensors on top defeats the purpose of having them. They'll have cool air flowing past them at all times. Most batteries start getting debris, etc on the top, which can clog the cooling passages. A temp detector on the bottom can pick this up. Put them on top and they won't. temp detectors on top will not detect any abnormal flow issues or heat issues..
     
    #2 TMR-JWAP, Jun 12, 2019
    Last edited: Jun 12, 2019
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  3. bmparent

    bmparent Member

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    Thanks for telling me that that's not a temperature sensor. This explains why it is where it is so I'll make sure I'll put it back. I'm using the newpriusbatteries kit. The manual recommends to put the 3 temperature sensors on top because of the design of the modules for reasons that I don't recall in this moment.
     
    #3 bmparent, Jun 12, 2019
  4. TMR-JWAP

    TMR-JWAP Senior Member

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    hmm..I was assuming you were rebuilding with prismatics.. 2K1 is a totally different design of modules, and I firmly believe 2K1 knows what he's doing. I doubt there's any way in the world the passages between those modules would ever get clogged. I'd probably go with what he recommends. It's his design.
     
    #4 TMR-JWAP, Jun 12, 2019
  5. bmparent

    bmparent Member

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    I'm in touch with him. I think it's likely it should go back to the position it came from if it's air intake, like you say. I'll see what he says. Since it's not something that actually touches or connects to the modules, maybe that's why it's not referenced in the manual. Luckily the connectors are all still in place so that it'll clip back on, theoretically...
     
    #5 bmparent, Jun 12, 2019
  6. bmparent

    bmparent Member

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    Just a quick update, I finished putting the 2K1Toaster battery together, put it in my car, and took 'er for a 40 mile test drive. No engine lights, SOC was at 6 blue bars 95 % of the time and I got an average 56MPG for the trip. My car hasn't run like this in years.
     
    #6 bmparent, Jun 16, 2019
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  7. George W

    George W Active Member

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    What was your average mpg before? Asking for a friend (not really, asking for myself).
     
    #7 George W, Jun 16, 2019
  8. bmparent

    bmparent Member

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    Before the original battery died, I was getting 52 in ideal conditions (good roads, no driving over 65, tires well inflated and aligned). After I had the reconditioned pack put in, the one that died last month after one month of service, I was only averaging 40-45 in good conditions. I haven't driven the new battery over the course of a whole tank yet, so I haven't got a tank average.
     
    #8 bmparent, Jun 16, 2019
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