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Need a quick response....Getting my HPWC installed today. Please help.

Discussion in 'Model X: Battery & Charging' started by Polar993, Sep 16, 2017.

  1. Polar993

    Polar993 Member

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    I am taking delivery of my X75D this afternoon, and my electrician is coming this morning to install my HPWC. (I know....nothing like waiting till the last minute! Today was the soonest my electrician was available.)

    My Model X does NOT have the 72A charging option. How should my electrician install and configure the outlet? I believe I have up to 100amps of service available.

    While I may not have the 72A charging ability in this Tesla, I want to provide the flexibility to have faster charging in the future if I ever get another Tesla with the faster charging capability.

    If some can please shoot me a quick response, I would really appreciate it!

    Electrician is coming in an hour and Model X is being picked up this afternoon.

    Thanks so much!
     
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  2. scaesare

    scaesare Well-Known Member

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    Have him configure the switch settings on the HPWC for the maximum current safely allowed by your circuit installation. If you have 100A breakers and wiring as per electrical code (likely #2 or 3 conductors), then that's 80A.

    Your current X will happily charge at the lower rate. But you'll be prepared for cars with larger chargers now or in the future.
     
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  3. Saghost

    Saghost Active Member

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    ^^^ What he said. The HPWC setting should be based on the wiring and what's available at the main panel. The two obvious choices are the highest that's available and the 60A breaker/48A draw that's the maximum your current car can support.

    You might ask the electrician about the difference, but typically the difference in cost for the heavier wires and bigger breaker is fairly small compared to the overall cost of the installation - assuming you have capacity in your main box for it.
     
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  4. boaterva

    boaterva Supporting Member

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    Right, people often think the wall is forcing the car to take it. But that's like thinking a 120 V 15 Amp circuit (normal house wall outlet) will force all that power to your 5 Watt iPhone charger. Be a good display of sparks if it did so!

    The answer is always the largest capacity line you can support from the panel and that you want to pay for up to the max of 100 Amps (80 Amps usable continuous) to future proof your install. Then you can support another car (larger charger?), someone dropping by (larger charger?) or even adding a second HPWC later and load sharing between the two (and each will get 40 of the max 80 Amps).
     
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  5. brkaus

    brkaus Active Member

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    Note that going over 60a may require a disconnect switch and thus higher cost. For many that just need typical overnight charging, 60a (48a actual charging) is the sweet spot as it should’t cost more than 50a.

    And yes, as mentioned above. If you have 100a available and it isn’t much more, by all means go for it.
     
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  6. Cowbell

    Cowbell Member

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    If you want to support high amperage charging, you will need a dual pole 100A breaker, and the hot conductors will need to be at least 4 AWG. The ground wire can be a bit smaller, but I would recommend nothing smaller than 6 AWG. There's lots of other details that can influence this spec, including what is available in your main panel as far as space and loading. Also, if you have a run over 100' that may impact wire size. However, anything larger than 4 AWG will probably not fit in the HPWC terminals without reduction of some strands.

    Local code may require a disconnect switch near the HPWC. which will add to the cost.

    Hope this helps.

    Rich
     
  7. Polar993

    Polar993 Member

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    Wow, awesome info guys....thanks SO much for the fast responses!!!

    So it looks like I should go with a 100A breaker if my wiring infrastructure and breaker panel have the capacity. Basically I should install the largest amperage breaker possible, even though my current Model D won't benefit from it. Future cars will.

    I just want to confirm that installing the higher amperage breaker won't make my charging inefficient. See below that I received from my OA just now. Looks like this is from the installation manual.

    "For Model S or Model X equipped with the standard on-board charger (48A), install the Wall Connector with a 60 amp circuit breaker for optimal charging. For vehicles with a High Amperage charger upgrade (72A) install Wall Connector with a 90 amp circuit breaker. For power sharing with more than one Tesla, install with as much power as possible, up to 100 amps."
     
  8. Saghost

    Saghost Active Member

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    The size of the breaker and wiring will have no meaningful effect on the charging efficiency (I can't say no effect because technically larger wiring will have lower voltage drop in the wires, but the differences are so small as to be irrelevant for any practical use.)

    Remember, the HPWC and all the wiring to and from it are basically just an extension of the grid, passing AC current through to the car's onboard charger module. All of the real work is done in that module, and differences in efficiency from different charge rates are based on what happens in that module (and how the cooling needs of the module and pack compare to the overhead cost of a longer session.)
     
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  9. boaterva

    boaterva Supporting Member

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    The OA doesn't know what he's saying with this cut and paste he got from somewhere. There is no 'optimal' with 60 Amps. You could have (let's be crazy) a 1000 Amp wiring setup. It would not change anything about what the car sees, as the current limit is just that, a limit. Perhaps Tesla means 'optimal' as in 'most efficient use of money', but I'd never call it optimal as people then think 'larger is badder'. Horrible choice of words.

    @Saghost puts it well, over a certain level, the size of the wiring and breaker have no effect except to raise the max current you can draw.

    And as I said above, you may want to future proof the installation with a 100 Amp circuit to allow cars with larger chargers to charge more quickly or to allow two HPWCs to load share. Installing a small wire gauge will cost a lot to redo later.
     
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  10. Zero CO2

    Zero CO2 a long term goal

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    If you only have 100 Amps into your home i am not sure why you need anything more than the following: ( my guess is for multiple electric vehicles you will need to upgrade your service to 200 amps)

    50 Amp breaker, associated 6 or 8 AWG cabling depending on distance from the main panel, HPWC connector set at 40 Amps, this will provide an typical commute of 70 miles of range in about 2.5 hours time overnight.

    Granted there are some folks who have unusual commutes and driving habits that require fast charging from home, but in almost all cases you will charge your vehicle while sleeping
     
  11. speedy

    speedy Member

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    If you have 100A TOTAL service available for your whole home, then you can't allocate all of that for charging. Your electrician should be able to evaluate the existing circuits in your house to determine the highest amount of charging current that makes sense, most likely 50A. Your car most likely has the 48A charger, which will require a 60A circuit, but that is only 20% more than the 40A that a 50A circuit will get you, so no point pushing it if your service cannot support it.

    If, on the other hand, you have 200A service and can allocate 100A for charging, your car cannot handle 72A charging anyway, so unless you intend to have two chargers installed, no point going with the 90A circuit.
     
  12. brkaus

    brkaus Active Member

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    Get the max available from the electrician and the pricing and decide. With an hpwc, up to 60a will likely all cost about the same.

    How many miles do you drive in a day?

    How many miles will the hypothetical second car drive per day?

    How far from the panel is the HPWC going to be installed?

    You mentioned 100a. Is that your main breaker size?
     
  13. jareade

    jareade Supporting Member

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    We finally installed our HPWC yesterday. Went with 100 Amp service. Our Model S only has a 48A charger, but our Roadster has 70A. And we figure any future Tesla we purchase will be at least 72A. So for us, 100A made the most sense.
     
  14. Polar993

    Polar993 Member

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    IMG_6695.JPG Thanks guys!

    What dip switch position should the charger be on? My electrician just installed a 100amp breaker.

    Should the dip switch be set to #9 at 48amps? Or should it be set to D at 80amps?
     
  15. jareade

    jareade Supporting Member

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    For me, we put the rotary switch to D. But I can use more than 48A now with the Roadster. I'll let someone else jump in with advice about what to set it at if only using 48A now and the foreseeable future. If you put it at 9 now, it would be a matter of just moving the switch to D at a later point when you have higher Amperage charging capacity.
     
  16. Saghost

    Saghost Active Member

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    If the electrician put in a 100A breaker and matching big wiring like I think you're saying, the rotary switch should be on "D".

    This setting tells the HPWC what to put on the pilot signal to tell the car how much current is available - cars that can't use all of that current are not adversely affected, they just take as much as they want.
     
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  17. boaterva

    boaterva Supporting Member

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    Right, exactly as the table says; the breaker for the circuit is 100 so the HPWC is up to 80 so it's D. This is the limit, not what it will use every time.
     
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  18. brkaus

    brkaus Active Member

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    Yes to D. No need to open it up if a friend stops by with a 72a charger in their car.
     
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  19. gjunky

    gjunky Waiting for the Model ☰

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    Yes to D.
    We went with a 100a breaker for our X and have it set that way. Our X can charge at (up to) 72a because we have the bigger charger in the car. Once we get the three, we'll install another Hpwc and link them hopefully being able to use the full capacity between the two cars
     
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  20. Polar993

    Polar993 Member

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    Thanks Guys.

    Unfortunately I saw some of these later responses before my electrician left and he set the config to #9.

    He was afraid of sending too much current to my battery.

    I guess it sounds like the lower amperage charging system is unaffected by the higher current, and I can safely set the output to D without harming my battery.

    Yes?
     

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