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Problem at Newark Supercharger?

Discussion in 'Model S: Battery & Charging' started by pdq, Apr 25, 2016.

  1. pdq

    pdq Member

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    Location:
    Philadelphia
    I pulled into the new Superchargers near Newark DE yesterday afternoon. 1 side of each of the 5 "pairs" of chargers were occupied, but 6 A & B were open, so I went to 6B. My battery at the time was in the mid 20% range. At first, things looking to be charging at a normal rate, then the rate of charging started to rapidly decline. I know that the charging slows down significantly as the battery starts to reach it's capacity, but I was far from that, so I started taking pictures on five minute intervals with my cell phone. Weather was good with an outside temp of 69F. Here are the results:

    Battery% W V A
    3:10 114 368 313
    3:15 95 373 256
    3:20 78 379 205
    3:25 66 382 173
    3:30 56 58 385 152
    3:35 62 54 388 139
    3:40 67 48 391 126

    Is this normal? If I'm interpreting the above correctly, the often repeated stat that Superchargers can add at a rate of 150 - 170 miles of energy in 30 minutes seems very doubtful. Am I interpreting the above correctly?

    If anyone in Tesla land wants to see the pictures I took, I'm happy to share them.

    pdq
     
  2. pdq

    pdq Member

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    For whatever reason, all the columns above were compressed versus how I had them spread out. The reason that starting at 3:30 there's an additional set of numbers as I included the % of batter charge, so in looking at the above jumble of numbers, work from right to left.

    pdq
     
  3. JohnQ

    JohnQ Active Member

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    Would be helpful to know your battery % at the start and end of the charging period along with whether you have a 60, 70, 85 or 90 kWh battery. I can't parse it out from your data.

    I'm presuming 3:10 to 3:40 is the 30 minute period where you recorded the data.

    I was at Newark on Friday and charged with no surprises so not sure of your experience.
     
  4. mikeash

    mikeash Active Member

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    It's hard to say without knowing the battery percentages for the first data points, but you don't look too far off normal. Compare to the graph in this post:

    Cold battery means not so super supercharge

    For your first data point with a battery percentage, you show 56% and 58kW, while that graph shows 70ish kW at that state. Your last data point is 67% and 48kW, while that graph shows around 55kW at that point.

    I'm not sure what the difference would be, but for example if you have a 60 or a 70 that would probably do it, since they'll taper off faster than the 85 I believe that graph is from.

    150+ miles in 30 minutes is doable, but you need to pull in when nearly empty for that to happen.
     
  5. pdq

    pdq Member

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    Thanks Mikeash, but as stated in my original post, my battery was in the mid 20% range when I pulled in.

    My car is a 2015 P90D which is 6 months old.

    I'd been driving almost consistently for 2 hours, and combined with the fact that the temps were at 69F as originally stated, I don't see how a "cold battery" could come into play, so the comparison to that graph wouldn't be relevant. Rather, I think I pulled in with absolutely prime charging conditions, but despite the fact that the battery went from mid 20's to 67%, charging slowed from 114W to 48W in the final 30 minutes of my stay..

    Is that steep a decline at only 67% charged normal?

    If you only pull into a Supercharger when nearly empty, you, my friend, are 100x braver than me!!!!! :)))

    pdq
     
  6. mmccord

    mmccord Member

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    Charging from 25 to 70% will be much slower than charging from 0 to 45%, even though the number of miles gained is the same.
     
  7. mikeash

    mikeash Active Member

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    The graph I showed is for charging with a normal battery temperature, even though the surrounding discussion is about cold. So, yes, a sharp decline like that is normal. And yeah, I don't pull in with zero miles remaining, a buffer is good, but if you're after charging speed you want to cut it as closely as you can.
     

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