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S60 @ 100% vs S75 @ 90%

Discussion in 'Model S: Battery & Charging' started by D.E., Oct 18, 2016.

  1. D.E.

    D.E. Member

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    The S60 is software upgradeable so has the larger S75 capacity battery. Since 100% charging is suboptimal, can the S60 be routinely charged to 100% which should be 80% of the full S75 capacity?

    I think the question comes down to whether the S60 unavailable charge is at the top or the bottom of the battery, in other words does a fully charged S60 fully charge the battery, then software limits capacity by not allowing the bottom 20% to be used or does the S60 only allow an 80% charge?

    It seems the latter would allow 100% charging of an S60 while maintaining battery longevity while the former would not.

    Anyone know?

    David
     
  2. WannabeOwner

    WannabeOwner Member

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    Yes

    Also, when charged to 100% (of the "60" capacity) Regen braking is still available.

    There is a detailed thread about this on here somewhere :)
     
  3. chillaban

    chillaban Member

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    Every time this conversation comes up, most agree that all evidence points towards the lower portion of the battery capacity being unlocked, so charging to 100% on a 60 is like charging 80% on the underlying 75.

    However, that doesn't change that Tesla's official recommendation is still to charge to 90% regardless of your model unless taking a trip, and the car still triggers "range charging may shorten battery life" warnings. Furthermore, the warranty also excludes "normal" wear and tear due to usage patterns, including normal battery degradation.

    So you do risk setting yourself up for a denied range loss warranty claim, however small the chances, because Tesla can point back to your charging habits of consistently charging to 100%.
     
  4. emir-t

    emir-t Member

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    I suppose at that point you could ask for the battery voltages or just ask for the pack SoC % instead of the virtual pack you purchased.

    All evidence points out to the new 60 pack being 80% of the 75. Value is still there while supercharging too, from all the data I could see it seems like Tesla is getting the taper rolling in later with the 60, resulting in the pack reaching full 4.2V per cell voltage earlier in the constant current stage of charging. They made it so that cells hit 4.2V per cell just at 100% aka 80% of the actual 75 pack. Be it a 75 they'd want the taper rolling in earlier to get cells reaching 4.2V per cell later on because after 4.2V has been reached per cell the constant voltage state starts, meaning they'll lower the current continiously so that voltage keeps at 4.2V.

    Overall supercharge session would take longer with the 60's late taper on 75 since it would make the CV (constant voltage) stage longer. While 60 doesn't care about the constant voltage state and gets the cells up there a little quicker, just at 80% to be specific. (100% of the 60)

    Great value for money IMHO. If I could afford it, I'd go for it.
     
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  5. MP3Mike

    MP3Mike Active Member

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    If you are getting to 4.2 volts/cell then the pack is at 100% of it's 75 kWh capacity. So if you are seeing the voltage get to 4.2 on a 60 that is software limited 75 Tesla has made it use 20-100% of the actual pack capacity. And you don't want to charge it to 100% all the time.
     
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  6. emir-t

    emir-t Member

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    Not when you're supercharging. Charging voltage gets to 4.2V. Just check when the good old 85 packs reach 403V (which is 4.2V per cell) A battery isn't full when it reaches the CV stage. If you stop charging as soon as you hit CV stage you'll see voltage falling down. See my post on the original thread where I wrote in more detail.

    With regular charging you're putting in amps in very low C rates to cells so it takes a long time for voltage to reach 4.2V, meaning it doesn't with the 60.
     

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