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HPWC wiring - 80 amp and non-dual charger car

Discussion in 'Model S: Battery & Charging' started by peakay, Mar 20, 2017.

  1. peakay

    peakay Member

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    Hi there,

    We are installing a 2nd gen HPWC and currently have P85 with dual chargers. If we instal it at 80 amp and later have a model 3 or other tesla without dual chargers, will they work OK with it? We will probably only keep our MS for another year or two and want to make sure we install this in the best way.

    Thanks!
     
  2. JHWJR

    JHWJR Member

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    The car and the charger handshake and the appropriate level of charging (including amps) is determined and delivered, subject to your power to make it even lower should you desire. There is no risk that your charger will deliver more than your future car can handle, though it is likely that your charger will be capable of delivering faster than your next car can take advantage of.

    Hope that answers.
     
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  3. Rocky_H

    Rocky_H Active Member

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    The connector on the wall doesn't "force" energy into the car, creating the problem you're thinking of, so it will be fine.
    Here's an analogy to picture it. Think of a buffet. There is a lot of food available, but it doesn't bury you under a pile of food if you approach it. The car is like your plate. You get to decide how much food to take, even though there is a lot more available.
     
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  4. bob_p

    bob_p Active Member

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    In 4 years with our S P85, and over 82K miles - we've really only needed to do charging at 80A once - and that was because there weren't any superchargers at that time, and we needed to have a full charge before making a road trip.

    We didn't order the 72A upgrade for our new S 100D - and should be fine with the 48A charging at home. We'll use the HPWC at 48A for the new S 100D - and for our dual charger S P85, we should be fine with running it off a 14-50 at 40A.

    And, if we ever really needed to fast charge the S P85, we could swap the cars in the garage, though that seems highly unlikely.

    When we can place the order for our Model 3 (to replace the S P85), we'll likely stick with the standard charger - and plan to charge at home at only 40A.

    Plus, the Model 3's will be lighter - with smaller battery packs getting longer range - so there'll be even less need to have high speed charging (which might not even be an option for the Model 3).

    I'd recommend doing what we did - if you have an 80A HPWC - plan to use that at the maximum setting for one car. And for the second, use a 14-50 outlet with Tesla's 14-50 cable (so you don't tie up a UMC) - which is much cheaper to have installed. And if you don't have enough amps to have both an 80A HPWC and 40A 14-50 running at the same time, then throttle down the HPWC so you can have both cars charging at the same time.
     
  5. DarkMatter

    DarkMatter Member

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    Consider this for a second. If the full capacity of something electrical was always used it would mean the following:

    - your phone battery would die instantly
    - you would never be able to turn a laptop off without unplugging it
    - it would be impossible to set a heater or hair dryer to low

    When they are working correctly electrical devices only draw the power they need. Now you know a bit more about how these things work together.
     
  6. tpham07

    tpham07 Member

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    Not to mention numerous destination chargers that may give out more power than your car can take. the car's system is smart, it can figure it out. Just plug and forget about it.
     
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  7. Saghost

    Saghost Active Member

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    Having the 2nd generation 80A HPWC installed has other benefits...

    If you get a second Tesla later, you can add another HPWC as a slave on the same circuit - and they'll talk to each other and each use the full capacity of the circuit when needed if the car supports it, or split the circuit when both cars try to charge at once.
     
  8. tga

    tga Supporting Member

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    That's not how electricity works. A power source can supply X amps. A load draws Y. As long as Y<=X, all is OK. The supply can't force X amps into the load.

    The charging station tells the car how much power is available. The car will draw up to that amount, but not more.
     
  9. tpham07

    tpham07 Member

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    i was saying that the car was smart enough that using a higher amperage charger than your car would not damage the car because it can figure it out and only take what it needs from the charger...the charger isn't going to force extra power into the car that the car won't accept.
     
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  10. DarkMatter

    DarkMatter Member

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    That still indicates a fundamental misunderstanding of electricity. You can't 'push' amps into a device. You can only push volts. Think of it this way: an old school light bulb is not a smart device. Yet a 100W one (about 1 amp) works just fine on a 15 amp circuit.
     
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  11. Joelc

    Joelc Member

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    And not to nit pick (ok, i am), but HPWC != charger. It's a connector.
    The charger is onboard and inside the car.
     

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