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Battery Voltage difference between models

Discussion in 'Model S: Battery & Charging' started by randvegeta, May 24, 2018.

  1. randvegeta

    randvegeta Member

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    I have a 2014 S 60 with 50kwh (estimated) usable capacity.

    Probably one or 2 of my modules has a dodgy cell in it, but even if that is the case, original capacity is only 58KWH usable? Not very much.

    Does the voltage of each pack differ depending on capacity?

    As far as I know, each module is about 4.5KWH (assuming no degradation), so I guess the S 60 has 14 modules? And an S 85 has 18 modules?

    Since there are more cells in the S 85, does that mean the voltage is higher?

    Does anyone know if there is some empty space in the S 60 packs where you can just insert 4 more modules and basically turn the car into an S 85?

    Anyone have any experience with this?
     
  2. MP3Mike

    MP3Mike Well-Known Member

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    The original 60kWh pack has 14 modules, with blank/empty cells placed throughout each module. The 85 kWh pack has 16 modules that are fully populated with cells. (The 70 kWh pack has 14 fully populated modules just like the 85 kWh packs.)

    No, you can not just add 2 modules to a 60kWh pack to make it a 85kWh pack.

    The 60/70 kWh packs are ~350 volts, while the 85/90/100 kWh packs are ~400 volts.
     
    • Informative x 1
  3. randvegeta

    randvegeta Member

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    This is interesting. Presumably then you could replace the 60kwh battery pack with a 70kwh battery pack and you don't even need to update the Tesla's computer. If the voltages are the same, it should just charge and discharge normally, but it will just have more power right?

    So will the BMU re-calibrate over time to account for the extra capacity?
     
  4. scaesare

    scaesare Well-Known Member

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    The car's firmware configuration knows what model it is. Simply swapping packs won't change that, and I suspect there will be some issues there.
     
    • Helpful x 1
  5. apacheguy

    apacheguy S Sig #255

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    Definitely cannot swap packs without updating the vehicle config.
     

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