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NEMA 14-50 question

Discussion in 'Model 3: Battery & Charging' started by octoad, Jun 11, 2018.

  1. Quickstart88

    Quickstart88 Member

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    Don't jinx me. But thanks for the warning.
     
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  2. P85_DA

    P85_DA Supporting Member

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    You will get 40a vs 32a with HPWC on 50a circuit ....seriously look at upgrading your panel though ..the car is a continuous load
     
  3. jerry33

    jerry33 (S85-3/2/13 traded in) X LR: F2611##-3/27/20

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    A 100 amp panel is really small. However, you can put in the 50 amp and set the car to charge at 32 or 33 amps. Because you'll likely be charging the car at night, the only other appliance that will be running during that time is the A/C.

    I'd seriously think about upgrading to a 200 amp panel, if possible.
     
  4. eprosenx

    eprosenx Active Member

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    Well the fact that you only have a 100 amp main service is new data. You need to run a load calculation to figure out how subscribed your existing service is. It is possible you are already overloaded! Most houses these days have a 200a service.

    Note that the actual rating of circuit breakers and the ampacity of the wire has nothing to do with the load calculation process. You calculate loads based on their nameplate ratings. So a 32a UMC Gen 2 on a 40a or on a 50a circuit is no different from a practical or a calculation standpoint.

    So the benefit of a wall charger:
    I always want to keep my UMC in my car for emergencies and the unexpected. And I am too lazy to plug in/out the UMC from a wall socket every day (also it can wear down the receptacle pins and it has some danger since the plug is hot when doing it). That meant I wanted a dedicated charger at home. So either a second UMC or a Wall Connector. I went with the wall connector since in my case it let me charge at the full rated 48 amps of the car. I put it on a 60a circuit (but you can put it on up to a 100a circuit).

    I personally think the Wall Charger is the best option for at home since you can change a rotary setting dial inside the unit to control exactly how many amps it will let the car use. I see this as especially useful when you have smaller electrical services (like you do) since you can dial in the max amount your service is calculated to be able to handle.

    Note that the car gives you even more granularity, but you can't trust the car from a NEC standpoint. My reading is that the dial in the Wall Connector counts as far as NEC goes, but the settings in the car rely on laymen humans and so they don't count. Also, the software has been known to reset itself and try to draw the max offered by a UMC or Wall Connector from time to time...

    A Wall Connector is only $500 when a second UMC is $300. It was an easy call for me.

    P.S. On 6 AWG Copper in conduit you can support a 60 amp breaker. Though as you have pointed out, your electrical service probably can't handle that much power. Though I see nothing wrong with putting in bigger wire and breakers, and just setting the dial on the Wall Connector down to an appropriate setting so you don't overload your main electrical service. One benefit of that is that you could later upgrade the main panel/service and you would be all ready to turn up the juice on the Wall Connector without re-wiring. Just food for thought...
     
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  5. Quickstart88

    Quickstart88 Member

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    Thanks again eprosenx.

    I wish I can drop a 200 amp breaker panel. Way too much red tape, townhouse, association, and perhaps the main line coming in the neighborhood can only do 100 amps. I am in So Cal and it's just too much BS.

    Electrician said if you overload the main panel, it will jump my entire main panel and therefore a good chance my entire house will be out of power for awhile. He said if I do 50 amps breaker even if you can dial down the wall charger, it will hog up the 50 amps initially and slowly dial down. That mean it will leave me with 50 amps to run all my other appliances. If I turn on my Central Air. Perfect storm situation, there is a risk.

    So using the UMC charge rate at 32 amps with the 40 amps breaker is a safe option. Giving me 60 amps to run all my other appliances.
    I just have to remember to never get a wall charger. Get a extra 2nd gen UMC. I am sure with Tesla Ramp up, these UMC Mobile connector will be cheaper and cheaper. Being that it's portable, there's going to be a lot of 5 fingers discount on craiglist for sale.

    I drive 20 to 30 miles a day. One to two hours charge at 32 amps giving me an average of maybe 28 miles per hour charge rate is more than enough for me. I am picking up my ride this Thursday. Electrician will swing by on the July 4th. If all goes well, I should be set. Go Elon! 7K made. We are seeing a new revolution. Just today I had to get gas for my ICE. Man I will missed waiting in line for Sam Club or Costco gas line.

    Overall, this is my best option and the safe route.
     
  6. Quickstart88

    Quickstart88 Member

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    Thanks Jerry33 and P85_DA
     
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  7. Leeclanual

    Leeclanual Member

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    Is it ok to leave the wall charger plugged into the 14-50 outlet when not plugged into Tesla?
     
  8. COrocket

    COrocket Member

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    Yeah I think most people keep it plugged in when not in use. It reduces the wear on the socket and you don’t need to carry the charger with you around town.
     
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  9. TexasEV

    TexasEV Well-Known Member

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    Of course. That’s what tens of thousands of Tesla owners have done for many years. The M in UMC is a capability, not a requirement.

    And the C stands for Connector, not Charger. The charger is in the car.
     

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