TMC is an independent, primarily volunteer organization that relies on ad revenue to cover its operating costs. Please consider whitelisting TMC on your ad blocker and becoming a Supporting Member. For more info: Support TMC

How many MPH on 120V @ 12A and 16A?

Discussion in 'Model 3: Battery & Charging' started by AWDtsla, May 30, 2018.

  1. AWDtsla

    AWDtsla Active Member

    Joined:
    Mar 3, 2013
    Messages:
    3,777
    Location:
    NE
    We know the Model 3 should charge miles about 30% faster than S due to efficiency, but we don't know if Tesla has managed to improve the large overhead while charging that leads to slow charging being very inefficient. Does anyone have real data on this, preferably captured with any logger other than the Tesla mobile app?

    My napkin math says [email protected] should be 5.75 MPH, including overheads
     
    • Like x 1
  2. KJD

    KJD Supporting Member

    Joined:
    Dec 14, 2013
    Messages:
    1,007
    Location:
    SLC, UT
    The Tesla doc says your number is a bit high. It looks to be more like 4 mph on this page.
    Screen Shot 2018-05-30 at 9.14.23 AM.png

    I think this is a good example of why you want to use 240 volts instead of 120 volts for charging.

    Screen Shot 2018-05-30 at 9.16.49 AM.png

    More details are here.
    Home Charging Installation
     
  3. P=VI

    P=VI Member

    Joined:
    Apr 8, 2018
    Messages:
    23
    Location:
    Columbus, Ohio
    I see around 3 to 4 MPH @120V/12A and 4.5 to 5.5 MPH @120V/16A.
     
    • Informative x 1
  4. Skotty

    Skotty 2014 Model S P85

    Joined:
    Jun 27, 2013
    Messages:
    2,203
    Location:
    Kansas City, MO
    This chart can be a little misleading. Take note that all rows are for 240v, even though some of the amps listed would be far more common at 120v (a model 3 will only charge 5.5 miles per hour on a standard 120v 15 amp outlet with charging at 12 amp).
     
  5. omgwtfbyobbq

    omgwtfbyobbq Active Member

    Joined:
    Aug 24, 2013
    Messages:
    1,246
    Location:
    Southern California
    I see 4+mph (mostly at 4mph, at times at 5mph) charging at 110+V/12A.
     
  6. AWDtsla

    AWDtsla Active Member

    Joined:
    Mar 3, 2013
    Messages:
    3,777
    Location:
    NE
    Thanks for the RTFM response, but those docs are inaccurate, if nothing else other than they lack precision. S75D would be almost 10% faster than P90D, depending on conditions. Just for one example.

    Real world data please.
     
  7. WileyTheMan

    WileyTheMan Peanut Gallery Member

    Joined:
    Apr 20, 2016
    Messages:
    852
    Location:
    Los Gatos, CA
    According to the car, using the UMC I got with the car provides a solid 4m/h on a 110v/12a circuit. I don't have a 16a circuit available.
     
  8. quantumslip

    quantumslip Member

    Joined:
    Mar 3, 2015
    Messages:
    259
    Location:
    Houston, TX
    Could someone retest but set to use kilometers? That would have better resolution and possibly provide a better idea of charging efficiency. Otherwise, a watt meter and other data could be used.
     
  9. AWDtsla

    AWDtsla Active Member

    Joined:
    Mar 3, 2013
    Messages:
    3,777
    Location:
    NE
    You get precision down to tenths of a mile using the API. Watt meter doesn't tell you what the internal losses are, therefore you can extrapolate nothing about the actual charging rate.
     
    • Informative x 1
  10. quantumslip

    quantumslip Member

    Joined:
    Mar 3, 2015
    Messages:
    259
    Location:
    Houston, TX
    didn't know the api had that resolution; if one only could use the car display the km would be your best bet.

    i guess watt meter would be useful if the amperage is rounded, but that is more of a rounding issue at that point
     
  11. AWDtsla

    AWDtsla Active Member

    Joined:
    Mar 3, 2013
    Messages:
    3,777
    Location:
    NE
    I would encourage you to use it for that purpose, you may find some interesting things. I'll leave it at that.
     
  12. GregRF

    GregRF Squirrel Power

    Joined:
    Jul 22, 2014
    Messages:
    356
    Location:
    CA
    According to TelsFi I was getting ~4.25mph on 12A. States around 72% efficient.

    Since I upgraded to 240V I've been getting ~30mph @ 32 amps and 90% efficient.

    Here are a few of the longer charges on 120V:
    upload_2018-5-30_10-29-12.png

    And my longest charge so far with 240V:
    upload_2018-5-30_10-31-5.png
     
    • Informative x 4
  13. jsmay311

    jsmay311 Member

    Joined:
    Apr 22, 2016
    Messages:
    715
    Location:
    Chicago suburbs
    Wow. That's a huge difference.

    Other studies I've seen comparing 120V and 240V charging efficiencies on Volts and Leafs have found much smaller efficiency penalties for using 120V instead of 240V... like only 2%-5% lower. (Excluding short-duration low-kWh charges, which show higher differences).
    A comparison of electric vehicle Level 1 and Level 2 charging efficiency - IEEE Conference Publication
    https://www.veic.org/documents/default-source/resources/reports/an-assessment-of-level-1-and-level-2-electric-vehicle-charging-efficiency.pdf

    The only explanation for this that I can think of would be if Model 3s / Teslas have much higher parasitic loads during charging than other EVs/Volts/Leafs(?). (Maybe the bigger battery could play some role in this as it would require more energy to initially heat/cool the larger pack to some target temperature for charging, but I wouldn't think the differences would be so dramatic unless it was charging in extreme temps.)
     
    • Informative x 1
  14. AWDtsla

    AWDtsla Active Member

    Joined:
    Mar 3, 2013
    Messages:
    3,777
    Location:
    NE
    It does, this is a main problem. It's not charger efficiency. This also means solar panels on the car are out of the question, because anything below ~300W won't even make it to the battery, you'll actually end up with a negative charge rate.
     
  15. GregRF

    GregRF Squirrel Power

    Joined:
    Jul 22, 2014
    Messages:
    356
    Location:
    CA
    Most of this charging would be taking place in 50-60 F ambient outdoor temps, so the parasitic losses shouldn't be due to temperature extremes.
     
  16. CWFLY

    CWFLY Member

    Joined:
    May 9, 2018
    Messages:
    46
    Location:
    San Diego
    FWIW, I charged my car last night via 120V/15A, which gave me roughly 110V at 12A. MPH fluctuated between 3 and 4.

    Two questions:

    1. Does anybody know what constant Tesla uses to convert Miles to kWh?
    ???? 310 mi / 75 kWh ????​

    2. How does the UMC know the difference between 15A and 20A for 120v? I know the 20A has a little bend in the tab, but is there some sort of logic/code built into the adapter? (probably answered my own question)
     
  17. AWDtsla

    AWDtsla Active Member

    Joined:
    Mar 3, 2013
    Messages:
    3,777
    Location:
    NE
    One of you brave early adopters can figure that out, and I'd really like to know. Get data from your car via API. Remote S app or teslafi will work for this. Enable high precision, and note "Rated Miles" before starting charge. Finish a long charge, then note "Energy Added" and ending "Rated Miles". Do this *immediately* after finishing charge, it may not be valid even minutes later.

    Energy added/(End-Start) = Rated Wh/mi.

    Repeat the experiment to confirm. You should get a number with very high consistency.

    Yes.
     
    • Like x 1
  18. CWFLY

    CWFLY Member

    Joined:
    May 9, 2018
    Messages:
    46
    Location:
    San Diego
    Here is a more accurate number...

    25 miles added in 6.5 hours = 3.8 MPH.
    Conditions: 110V/12A, around 67F.

    begin-IMG_5573.JPG end-IMG_5578.JPG
     
    • Informative x 2
  19. eladts

    eladts Member

    Joined:
    Jul 31, 2016
    Messages:
    236
    Location:
    Brookline, MA
    In order to charge at 120V/16A you have to use the optional 5-20 adapter for the UMC. This adapter will not physically fit to 5-15 sockets, as the neutral blade is rotated. If you use the standard 5-15 adapter there is no way for the UMC to know that this is a 20A circuit.
     
  20. timk225

    timk225 Active Member

    Joined:
    Mar 24, 2016
    Messages:
    1,237
    Location:
    Pittsburgh
    My 3 consistently shows 5 mph on both the in car screen and on the phone app when charging at 118-119 volts and 12 amps. This could really be anywhere from 4.50 to 5.49 mph due to rounding. I don't always charge on a 5-15, but I've done it to try it out a few times.

    My 14-50 plug charges at 31 mph on 243-244 volts and 32 amps.

    I'm installing a 6-20 this week to charge the car when it's too much hassle to get the 15 foot 14-50 extension cord out and unplug the oven. My Tesla mobile connector adapter is on the way now.
     

Share This Page

  • About Us

    Formed in 2006, Tesla Motors Club (TMC) was the first independent online Tesla community. Today it remains the largest and most dynamic community of Tesla enthusiasts. Learn more.
  • Do you value your experience at TMC? Consider becoming a Supporting Member of Tesla Motors Club. As a thank you for your contribution, you'll get nearly no ads in the Community and Groups sections. Additional perks are available depending on the level of contribution. Please visit the Account Upgrades page for more details.


    SUPPORT TMC