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Does supercharging harm the battery?

Discussion in 'Model S: Battery & Charging' started by GenIIIOwner, Nov 16, 2012.

  1. GenIIIOwner

    GenIIIOwner Member

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    Hi all,

    I'm trying to figure out whether or not I need the supercharger? I know that any high-amperage charge is bad for the battery, but how much does it actually effect the pack?
     
  2. jerry33

    jerry33 S85 - VIN:P05130 - 3/2/13

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    It only charges at full rate for the bottom half of the battery. At 50% the rate is reduced by half and I believe it goes down even more as it approaches full. There shouldn't be any more deterioration than with a home charge.

    What's bad for the battery is charging to 100% (range charge) and then leaving it sit at 100%.
     
  3. Jason S

    Jason S Model S Sig Perf (P85)

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    It isn't that high-amperage is bad, it is just that a Roadster owner verified charging at 30-40 amps was optimal for that car.

    Could charge at higher amps, but lose electricity to overhead like cooling. I don't think anybody has measured it and shared the results for the Model S yet.
     
  4. stopcrazypp

    stopcrazypp Well-Known Member

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    The specific cells that the Model S uses were cycle tested at 0.5C (AKA fully charged from 0%-100% in 2 hours). Other Panasonic 18650 cells are cycled at 0.7C. The supercharger at peak power charges at ~1C (90kW of power to 85kWh of battery). In general charge rates peaking at 1C is perfectly fine for most 18650s (as in you will get the rated life of the cell).
    http://www.teslamotorsclub.com/showthread.php/5220-Panasonic-cells-for-Model-S/page2?p=61317&viewfull=1#post61317
    http://batteryuniversity.com/learn/article/charging_lithium_ion_batteries

    As for the relative effects of different charging rates on battery life, I wasn't able to find data on that (there's plenty of data though that shows high temperatures and storage at or near 100% for long periods of time significantly degrades the battery).

    Like Jason S says, there's data on the efficiency of various charge rates for the Roadster (that's easier to gather since you can do so with only a few charging sessions). Battery life characteristics is harder to gather because you have to do hundreds of cycles to do so.
     
  5. Larry Chanin

    Larry Chanin Model S Perf Sig 1055

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    Jerry,


    I understand that the communication between a Tesla Supercharger and a Tesla battery is much more sophisticated than conventional fast chargers. However, do you know for a fact that when Supercharging in Range mode that the average current after 50% state of charge does not exceed the current during home charging in Range mode? Or stated another way, does the Supercharger really convert itself to a home charger after it reaches 50% state of charge?

    Based on Tesla's statements I have little fear that Supecharging in Standard mode hurts the battery. Likewise Tesla is clear that charging in Range mode will definately accelarate the deterioration of the battery. While I seriously doubt that Supercharging in Range mode a few times would "murder" the battery, I'm just not convinced that Supercharging in Range mode would be no worse than home charging in Range mode.

    Larry
     
  6. strider

    strider Active Member

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    Hi Larry, not sure what your point is as I believe you and Jerry are in agreement that supercharging in standard mode is no different to the car than AC (home) charging. The folks who used the SC's in Gilroy and let them sit for awhile noted that the charge rate continues to taper off as the battery fills up.
     
  7. Larry Chanin

    Larry Chanin Model S Perf Sig 1055

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    I was under the impression that Jerry was saying the Supercharging in Range mode is not different to the car than charging at home. We all agree that the charging tapers off as the battery fills up. The question does it taper off to the same degree as a home charger?

    Larry
     
  8. richkae

    richkae VIN587

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    Tom Saxton ( Roadster owner ) tested charging the roadster at different rates - to find out which was the most energy efficient.
    Tesla Roadster Charging Rates and Efficiency - Tom Saxton's Blog
    The testing had nothing to do with what was bad for the battery - it would take years and many cars to do those tests, and be very hard to isolate the variables. We have very little hard data on what is "bad" for the battery at this time. It is most probable that the charging rates supported by the roadster are indistinguishable in terms of battery degradation. All the other factors are likely to reduce any difference from charging rate into rounding error.
     
  9. Eberhard

    Eberhard #421 Model S #S32

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    #9 Eberhard, Nov 17, 2012
    Last edited: Nov 17, 2012
    supercharging will not murder your batterie. i assume that you will immediately leave the supercharge and continue your travel. Even then charging in range mode will not hurt your batterie. But you will loose on time because the current will constantly drop and charging will slow down. better go off after 30min and head to the next supercharger. only charge high and sit will damage your batterie over time. the cells used in Model S 85kWh are even more stable as those used in the Roadster and in the 60kWh and 40kWh pack.
     
  10. jerry33

    jerry33 S85 - VIN:P05130 - 3/2/13

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    My understanding is that because of the spacing of the Superchargers (SC) you won't normally have to do a range charge using an SC. Doing a standard SC charge should cause no more degradation than doing a standard home charge because of the cooling ability of the Model S and the SC's reduction in power after 50% is reached. Presumably (needs confirmation) if you do a range charge in an SC the rate of charge will slow down to the same as a home range charge so it will (confirmation needed) take much longer to get that extra 10% of charge. As I understand it, the SC plan is to start charging when about 25% of the charge is left and charge to about 75% or 80%. (30 to 60 minutes), then drive to the next SC.
     
  11. bonnie

    bonnie Oil is for sissies.

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    [mod note: I changed the title from 'Does supercharging murder the battery?' to 'Does supercharging harm the battery?' to better reflect the discussion. b.]
     
  12. Larry Chanin

    Larry Chanin Model S Perf Sig 1055

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    Thanks Jerry,

    I agree that the practical aspects of Supercharging, and not waiting forever at the Supercharger, will render academic discussions regarding harming the battery moot. In other words, due to practical considerations there rarely would be a need to risk Supercharging in Range mode.

    Larry
     
  13. Brian H

    Brian H Banned

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    The only exception I can think of is when planning to leave the "Charger Net" before getting to the next S/C, and wanting to get as far as possible before having to do a slow-charge.
     
  14. garry753

    garry753 RoadsterS753 ModelS P1449

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    Now that people are finally getting to do some realworld tests of the Supercharger network (waiting for them patiently down here in Texas), are you seeing any any negative effects on battery life?
     
  15. EcoHeliGuy

    EcoHeliGuy Member

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    If there was any chance of this we a few year away from knowing, giving family and friends joy rides will Likily effect the pack sooner.
     
  16. lolachampcar

    lolachampcar Active Member

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    We have one solid data point. Tesla is responsible for the battery for 8 years with unlimited milage using the SuperCharge (of thier design). If it hurt the battery, the people that warranty it would not be the ones providing the gun to kill it.
     
  17. William3

    William3 Member

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    Tesla's battery warranty doesn't cover the kind of damage (slight loss of charging capacity) that the superchargers would cause.
     
  18. stopcrazypp

    stopcrazypp Well-Known Member

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    The impact is so negligible it'll take years and tens of thousands of miles to see any differences. Think of it as increased wear, not "damage".

    Plus as I pointed before, you will likely still get the rated life of the battery using range charging + supercharging (what Tesla expects is ~70% capacity in 7 years and 100k miles), because that's how 18650 batteries are tested in the first place. But if you want to get more life out of your battery than what Tesla expects, shallower cycles will help (don't use range charge that often). Charging speed seems to have less effect.
     

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