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SR & SR+ Battery Questions & Thoughts

Discussion in 'Model 3: Battery & Charging' started by Blu-Ion, May 3, 2019.

  1. Blu-Ion

    Blu-Ion Member

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    Here are some random thoughts I have regarding SR and SR+ model (Mid range as well). Perhaps these questions have been asked before, more concerned about some of my questions and thoughts lower down

    1) The battery is the same 75kw as LR, just software locked to a lower capacity, correct?
    2) Can you unlock the battery (for a fee) to go from SR to LR for example in the future?
    3) Assuming its the same battery pack, the SR+ model is at approximately 75% capacity at "full charge" (give or take %), does this mean that 75% of the batteries are at 100% and the rest are at 0, or is the power spread across all the batteries evenly
    4) Assuming its spread across all the batteries, then if you have an SR, SR+ or MR model, you could in fact charge to 100% every night without any degradation fear, correct? .. since you never really charge to 100% battery cell capacity
     
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  2. MP3Mike

    MP3Mike Well-Known Member

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    1) No.
    2) No.
    3) No.
    4) No.

    The SR and SR+ share a battery pack, the MR has a different battery pack, and the LR is yet another different battery pack.

    So if you have an SR when you charge to 100% you are actually only charging the physical pack to 90%. (Once Tesla gets the software updated.)
     
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  3. Blu-Ion

    Blu-Ion Member

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    Awesome thanks for the insight
     
  4. eprosenx

    eprosenx Active Member

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    Also, the MR and LR technically have the same "pack", but they just de-populated some of the cells in the MR one. So it is not software locked, but it is technically the same "pack" style. My understanding was that the SR/SR+ was a total pack redesign for the smaller pack.
     
  5. GigaGrunt

    GigaGrunt Member

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    Correct
     
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  6. Zoomit

    Zoomit Active Member

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    I was thinking that the initial SR modules were similar to the MR/LR module design, just with fewer live cells, and in the same pack enclosure. Then, when the new TGA line(s) are operating, they'd start the manufacture of SR modules that are better optimized for manufacturability (speed/cost) with maybe a reduced weight or better weight distribution.
     
  7. GigaGrunt

    GigaGrunt Member

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    ‘New’ SR/SR+ modules running on pretty much all lines. TGA line helps with overall efficiency in running all modules. Depop modules phased out. Pack enclosure the same, just reconfigured for SR size.
     
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  8. Zoomit

    Zoomit Active Member

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    #8 Zoomit, May 5, 2019
    Last edited: May 5, 2019
    I hadn’t thought about all the different module configurations before. LR would have two different module configs (inside and outside) and SR would have another two, unless they designed the four SR modules to all be the same size and be interchangeable into any of the four positions. They probably had room for that so that’s where I’ll put my money.

    That would be just three unique module designs going into four pack enclosures: LR 1PH & 3PH plus SR 1PH & 3PH.

    This of course assumes the modules are not sided and have a unique config for their position on the left or right side of car. If so, shoot that engineer!
     
  9. GigaGrunt

    GigaGrunt Member

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    LR has two sizes. Base is built the same for both, larger is inner but needs to be configured to a left or right, smaller is outer, needs to be configured for left or right. SR has one size, one base, configured to be inner or outer. 1PH and 3PH handled by the penthouse, not at module level.

    All the lines trying to manage different configurations is inherently more complex than just 2 lines handling the different configurations.
     
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  10. Zoomit

    Zoomit Active Member

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    Bummer on the four LR module designs then. At least the SR modules sound easier to deal with. It’s amazing how a relatively simple product line gets sooo complex so quickly.

    I’m hoping someone designed the SR modules to be flexible enough to fit in Semi pack enclosures. Though on second thought, they’ll learn a lot before that goes into production and will likely plan to continue to iterate the design. The only thing that’s constant is change!
     
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  11. GigaGrunt

    GigaGrunt Member

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    Not necessarily 4 LR module designs. There are 2. Once the base modules get to a certain sort of the process, they get a couple pieces of hardware mounted that determine if its left or right. 75% of the production process can make the short or long base module, then move on to the next. Only 2 portions o the overall line really deal with the configured module.
     
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  12. Zoomit

    Zoomit Active Member

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    And it sounds like the SR modules are easier yet. I’m looking forward to a tear-down video of the SR pack—really curious to see how the cells are distributed within the module for inertia and thermal management. The extra volume available in the pack provides some interesting options.
     
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  13. GigaGrunt

    GigaGrunt Member

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    Cells within modules are same as LR. Bricks are less dense. Thermal management the same as LR. Module just shorter.
     
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  14. peakshaving

    peakshaving Member

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    Is the enclosure still able to accept LR modules or does the reconfig of the enclosure prevent that? That is- Could someone swap in LR modules into the SR pack?
     
  15. GigaGrunt

    GigaGrunt Member

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    Physically, yes. Would need a penthouse for the correct configuration. Multiple firmware flashes to make it work.
     
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  16. peakshaving

    peakshaving Member

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    Good to know! might be a fun project to do in the far future when my car's out of warranty.

    By lower density bricks do you mean there's dummy cells in the bricks? Wouldn't it have been simpler for production to just round up to the nearest brick count per module? That way you could use the same bricks for all your packs.
     
  17. MP3Mike

    MP3Mike Well-Known Member

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    I think all of the Model 3 pack variants have the same number of bricks. (They are wired in series, so they control the voltage of the pack.)

    Also, the bricks aren't physically separate units, it is just how the cells are wired inside the module.
     
  18. Dan123

    Dan123 Member

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    What the difference in the SR+ and MR battery packs? MR had a 264 range, and SR+ has 240 range. That's less than 10% difference.
     
  19. Zoomit

    Zoomit Active Member

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    Lots. As I understand it, MR packs contain depopulated modules that are basically the same design as LR modules. SR packs have modules updated specifically for the reduced cell count and do not contain inert filler cells.
     
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  20. GigaGrunt

    GigaGrunt Member

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    No dummy cells in 'new' SR/SR+ packs. Lower brick density is less cells per brick.
     
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