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Charging at 30amps

Discussion in 'Model S' started by mbhforum, Jan 25, 2017.

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  1. mbhforum

    mbhforum Member

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    Just got my CPO and noticed when plugging into my 14-50 outlet that I am only charging at 30amps. According to the manual, I might have a problem with my outlet/electric. Anyone else experience this? I texted my electrician too.

    Note: If Model S is charging and detects unexpected fluctuations in input power, the charging current is automatically reduced by 25%. For example, a 40 amp current is reduced to 30 amps. This automatic current reduction increases robustness and safety in situations when a problem exists outside of Model S and its charging electronics. For example, a home wiring system, receptacle, adapter or cord is unable to meet its rated current capacity. As a precaution, when Model S automatically reduces a location's current, it saves the reduced current at the charging location. Although you can manually increase it, Tesla recommends charging at the lower current until the underlying problem is resolved and the charging location can provide consistent power.
     
  2. DMC-Orangeville

    DMC-Orangeville 85D and John Deere 5100E

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    You might have a Canadian 14-50 adapter. They are rated at 32 amps. The odd Canadian CPO ends up in the USA
     
  3. mbhforum

    mbhforum Member

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    Here is a pic of my outlet.
     

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  4. steve841

    steve841 Active Member

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    Don't sweat it... mine does the same thing.

    Personally, I think Tesla did this to help prevent meltdowns with the UMC.
     
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  5. Manzacoty

    Manzacoty Member

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    Mine does the same thing too - everything tests out fine though (with the outlet). I just bought a HPWC and will install this weekend so we'll see how that does. 30 amps is fine with me though for my typical daily needs.
     
  6. msnow

    msnow Active Member

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    It remembers the amperage and location of the last successful charge. Try manually upping the AMP's to 36. If either the car or your panel doesn't like that setting it will automatically downamp your setting back to 30A again so don't worry that you'll break anything.
    Mine used to do the same thing until I had the electric company come out and clean up the power coming from the street.
     
  7. jf2go

    jf2go Member

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    Happens to me as well. I set it to 40A, and it charges at that current for a period of time (days/weeks). Then, for no reason I can determine, one night it starts charging at 30A and stays that way. My remedy is that I have to stay up until the scheduled time for charging to begin and manually change the current back to 40A. It then stays that way through the night and for the next few days/weeks, until it decides to change to 30A again.
     
  8. mbhforum

    mbhforum Member

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    I can set it for 40 manually, but then next time it charges, it goes back down to 30.
     
  9. TexasEV

    TexasEV Well-Known Member

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    There is likely something wrong with your power, anything from the transformer to the outlet, if the safety mechanism keeps kicking in and dropping to 30A. Have an electrician check your setup, it could be dangerous.
     
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  10. msnow

    msnow Active Member

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    Did you try my suggestion to try it at 36 AMPS? Was your charger installed professionally?
     
  11. mbhforum

    mbhforum Member

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    I haven't tried 36 yet. Yes, my electrician who might be reading this installed it.
     
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  12. BestRadar

    BestRadar Member

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    MIne also charges at 30 amps which is actually plenty for me. That is roughly a 30 miles per hour charge and even if battery was empty there is no issue with charging to full over night.
     
  13. ev-now

    ev-now Member

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    Those who have said "mine does this" are indeed right that it is fine, as the manual says, that's the point of the reduction. However it is indicating that there is a problem - it only backs off if there is significant fluctuation, voltage drop over time (and other factors).

    Dropping occasionally as jf2go experiences could easily be supply to the panel, but if it's backing off every time - something is not right. Of course the something not right might be another load on the panel, not necessarily the circuit supplying the MS.
     
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  14. hingisfan

    hingisfan hingisfan_Mark_V

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    Mine does it more in the winter (kick down to 30 amps while charging). I have a very long wire run and I'm assuming I have a bit of voltage drop which makes the car kick down to 30. I gave up trying to figure it out, 30 is fine.
     
  15. TexasEV

    TexasEV Well-Known Member

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    Can't be. It takes 240V at 40A to give roughly 30 miles per hour charge (29 to be exact) in Model S that aren't performance versions.
     
  16. BestRadar

    BestRadar Member

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    Maybe my last charge made it to 40A, I know it said 30 miles per hour. I am at 75% but I will plug it in shortly and see what its showing.
     
  17. Yitt

    Yitt Member

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    Same thing happens to me all the time. I used to manually bump it back up to 40 but it always reverted. The power at my house is dodgy on its best day so I'm not surprised there are fluctuations. Fortunately, even at 30 I still always have plenty of time to get a full charge overnight, so I stopped worrying about it a while ago. Glad to hear from others this is not unusual.
     
  18. MorrisonHiker

    MorrisonHiker S 90D 2017.42

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    It should show 22-23 mph at 30 amps, depending on your voltage.
     
  19. jerry33

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

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    Note that it doesn't reset manually. If your electrical utility has dodgy electricity (like mine does) it will lower to 30 every so often. Then you have to reset it. The thing to do is to lower the setting by two amps and see if it stays. If it doesn't lower it by two more until you get a stable number (which will almost always be higher than 30.

    Note that if your service amps are small or there is some wiring problem, then when some motor comes on, it can lower the charge rate (although what happens to me is that charging stops for a moment and then resumes at the same rate).
     
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  20. BestRadar

    BestRadar Member

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    Looks like I was connecting at 40A to get the 30 miles per hour. The amps change from charge to charge and usually I get 30A but did not pay attention to when it actually charged at 40A.
     

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