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

What ameprage do you supply your Wall Charger?

Discussion in 'Model X: Battery & Charging' started by studioloft, Nov 4, 2019.

  1. studioloft

    studioloft Gavin

    Joined:
    Nov 4, 2019
    Messages:
    38
    Location:
    Norwalk, CT
    I just purchased a Gen 2 Wall Charger. I am reading in the manual that you can supply anywhere from 20A to 100A to the charger. I am reading in the manual that if I feed the charger 100A it will supply the car 80A of power. I currently have a 200A service on my 1500sq ft house. (Central AC, electric stove, clothes dryer, etc.

    I just upgraded my home's service from a 100A to a 200A service. At 100A every time the AC kicked in all the lights in the house would dim. On that note is it the most wise decision to feed the charger off a dedicated 100A breaker? Living in Connecticut I am aware there are also certain electrical codes for what size pipe & gauge of wire must be used for a given amperage. I am thinking there might be a sweet spot for how many amps to feed the charger or what might be considered a sweet spot.

    Any help would be appreciated!
     
  2. Tdreamer

    Tdreamer Supporting Member

    Joined:
    Sep 10, 2017
    Messages:
    629
    Location:
    Bedford, Massachusetts
    How much you want to send to the wall charger kinda depends on the car and it's charging capabilities (75D vs. 100D, date of manufacture as that may impact if it can charge at 72A vs. 48A max) and you're charging needs (how many miles you tend to drive daily and how often you anticipate charging.

    I have a 90A breaker / 72A wall charger at our house, with 200A service to the house. It was installed when I got my Sept '17 X100D, and it being my first experience with a Tesla & EV, I didn't want any limits on how quickly the car could charge. In the two years of ownership and charging at home, I can say I probably took advantage of that high charge rate only a couple of times meaning I arrived home at a low state of charge and wanted a relatively quick recharge to enable me to meet the next day's anticipated driving needs. The rest of the time, I could easily have made due with half that charging capacity. If you're relatively near a supercharger (Darien & the under construction V3 chargers in Fairfield on I-95), that could cover any fast-charging needs.

    My suggestion would be to cost out the 90A breaker/72A charging option vs. a 60A/48A charging option and do what makes sense to you for you're budget.
     
  3. DCGOO

    DCGOO Active Member

    Joined:
    Nov 24, 2015
    Messages:
    1,195
    Location:
    Indianapolis, IN
    I have an X capable of 72 amps and a 3 capable of 48. Two WC shared 60 amp circuit. WC configured for 48 amp. I can charge either car separately @ 48 amps, or simultaneously @ 24 each. Both cars typically daily charge in less than two hours. I don’t start charging until 3 AM. If I arrive home from a road trip really empty, I might start charging earlier. The only scenario that might be problematic is if both cars happen to arrive home with a very low SOC. That has never happened.
     
  4. ajdelange

    ajdelange Banned

    Joined:
    Dec 10, 2018
    Messages:
    1,077
    Location:
    Virginia/Quebec
    What happens if you set the X to charge at 40 amps, get it started and then come along and plug is the 3? Does it give the 3 what is left over (8A) or does it lower the X's rate to 24?
     
  5. DCGOO

    DCGOO Active Member

    Joined:
    Nov 24, 2015
    Messages:
    1,195
    Location:
    Indianapolis, IN
    It sets both cars to a max of 24, until one drops off. If one car was charging at 48, when you plug in the second, it drops to 24.
     
  6. brkaus

    brkaus Well-Known Member

    Joined:
    Jul 8, 2014
    Messages:
    6,444
    Location:
    Austin, TX
    In most cases, over 60a requires a local service disconnect. And those get more expensive over 60a... so I feel, in general, 60a is the sweet spot.

    I put mine on a 50a breaker due to an EV electric plan available here. I’m easily able to charge two cars (alternating evenings) based on our moderate mileage.
     
  7. ajdelange

    ajdelange Banned

    Joined:
    Dec 10, 2018
    Messages:
    1,077
    Location:
    Virginia/Quebec
    Something that came up recently: If you are over 60A install a transfer switch instead of a disconnect. It must be of the ON - OFF - ON type so that it does the disconnect function. This will allow you to install two chargers from different manufacturers should you want to do that in the future while satisfying the requirement for only one EVSE on a branch.

    Just to be clear up to 4 HPWCs count as 1 EVSE because of the intercommunication between them.
     
  8. studioloft

    studioloft Gavin

    Joined:
    Nov 4, 2019
    Messages:
    38
    Location:
    Norwalk, CT
    Incredibly useful information! Thank you.
    My electrician is slated to do the install in 3 weeks and is waiting for me to get back to him on what amperage I want to supply it.

    Is there a chart somewhere or do you know where I can find what versions of the Model X support what levels of charging speed? I am currently deciding between 2017, 2018 and 2019 cars (FSD) that are either P100D/L models or just 100D models.
     
  9. ajdelange

    ajdelange Banned

    Joined:
    Dec 10, 2018
    Messages:
    1,077
    Location:
    Virginia/Quebec
    X's manufactured through December of 2018 will support charging up to 72 amperes (requiring an 90 A circuit) if equipped with the fast charging option. After that the maximum is 48 amps (requiring a 60 Amp circuit). The maximum a single HPWC can supply is 80 A but multiple (up to 4) HPWC's can supply a total of 80A requiring a 100A circuit.

    One can only have one EVSE on a circuit but multiple HPWCs (linked together) constitute 1 EVSE. Bottom line being that if you think you may want to charge more than one Tesla at a time install a 100A circuit. There is no point in going higher.

    But note that you could run a, say, 200Amp circuit to a subpanel and run multiple EVSE branches from that.
     

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