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Would Inconel improve the P85 (not D)? Why or why not?

Discussion in 'Model S: Driving Dynamics' started by MrJones390, Jul 21, 2015.

  1. MrJones390

    MrJones390 Space Boat

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    Even though there is no Ludicrous upgrade available for P85, I'm wondering, from a technical standpoint, if it could done and what the result would be. I'm guessing it makes no sense, otherwise Tesla would offer it.

    Start the mansplainin'!
     
  2. Jason S

    Jason S Model S Sig Perf (P85)

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    Googled Inconel just to find out what it was. Now that I see what it is, I don't understand how it would be used.

    The new battery pack has 90Kwh, up from 85. That, combined with the contact (or w/e, I really haven't been following this closely), enables a greater transfer of power versus the old P85D.

    Depending how that power is distributed, you might have a case for providing a bit more power to the rear wheels for the P85 but you'd need really sticky wheels to get that extra to the ground imho. My P85 with stock Conti wheels slips a little when flooring it, so an extra 50hp or so from a better battery pack plus xfer prolly wouldn't mean much. Maybe an increase from 4.0s 0-60 to a 3.8s? And that might be optimistic.
     
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  3. mgboyes

    mgboyes Member

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    The P85's peak power output is constrained by its single motor/inverter, not by the current supply limit of the pack.

    Its performance is constrained by traction at low speeds, and by the motor power limit at higher speeds.

    None of these would be improved by having a different contactor in the pack.
     
  4. AmpedRealtor

    AmpedRealtor Active Member

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    Surely applying the Ludicrous updates to a P85/+ would result in greater rear motor output, wouldn't it?
     
  5. mnx

    mnx 2013 P85

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    I've wondered the same thing, but from what I can tell it would make no difference. At 1300A output and an empty pack voltage of 350V (I think Ive seen that # tossed around) that's 455kW. Applying the updates to extract the extra 200A would make no difference since that's already higher than the 320kW or so the P85 outputs.
     
  6. WarpedOne

    WarpedOne Supreme Premier

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    P85 is limited by battery power.
    S85 is limited by inverter/motor capabilites.
    Everything is ultimately controlled by FW that constantly monitors voltage and current and compares with know max values.

    Tesla *might* reprogram P85 upgraded to P90 to draw more current. Or they might not.
     
  7. jaguar36

    jaguar36 Member

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    I think it probably would. There is another thread on this, but Inconel is actually a trade name for a family of alloys, so it would depend what exactly they were using before and after. In general though Inconel has excellent fatigue properties, particularly at high heat. Therefore its likely that the Inconel contractor has significantly better fatigue properties than whatever they were using before. It wouldn't improve performance, but would improve long term reliability. This is further substantiated by the fact that the ludircous upgrade came about from research into making the power train more reliable.
     
  8. mgboyes

    mgboyes Member

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    Source?

    In any case there's no way a P85 can benefit from a fuse that allows a 1300A limit to be raised to 1500A.

    It might be that the P85 has a much smaller fuse that could simply be replaced with a higher capacity but equally dumb replacement, but the 1300->1500A bump makes no difference since the drivetrain can't make use of 1300x350 = 455kW anyway.
     
  9. jbcarioca

    jbcarioca Active Member

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    According to Elon the contactor is presently limited to a 1300a draw, with the Inconel contactor the draw can be up to 1500a. The heat from >1300 a would melt the old fuse and also overheat the contactor. Their custom Inconel has a higher melting point and the new fuse is software controlled to be far more precise than was the old conventional fuse.
    In theory the more precise temperature management could lead to greater battery pack and drivetrain longevity. It will not be a surprise if similar processes show up across the board, with or without extra power.
     
  10. mgboyes

    mgboyes Member

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    My point was that on a P85 there is no performance benefit from moving to a 1500A fuse and uprated contactors, since the P85 drivetrain never draws more than about 900A anyway. Since the fuses and contactor aren't the rate-liming component in a P85's drivetrain, upgrading them doesn't help.

    It's true that an inconel/smart-fuse pack may have a longer life, or lower failure rate, but it won't make the P85 any faster. Over time I expect all packs will be built with the inconel and smart-fuses - after all they did say that this came about as part of a research project to extend drivetrain lifetime.
     
  11. J1mbo

    J1mbo Member

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    I thought that the fuse & inconel also allow the system to deliver more power between 30-60mph, which is definitely one area the P85 could be improved.
     
  12. jbcarioca

    jbcarioca Active Member

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    They permit higher amperage in all circumstances, but Elon said that 0-30mph was traction-limited so no increase in delivered power would happen anyway.
     
  13. J1mbo

    J1mbo Member

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    I said 30-60? Agree that 0-30 won't change, hard enough to use the power that's there, more power would be wasted.
     

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