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50 to 30 amp RV adapter

Discussion in 'Model X: Battery & Charging' started by Lindamon, Nov 14, 2019.

  1. Lindamon

    Lindamon Member

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    CFE54BCF-86EC-4A1B-815D-ACF8D7F1AB26.jpeg I have the Nema 14-50 50 amp charger adapter, and am familiar with RV parks. Some of the state parks only have 30 amp service.

    can I use my 50 to 30 amp adapter with my Tesla? In other words can I plug Tesla’s 1450 adapter into my 30 amp adapter I use with my 50 amp RV when only 30 amps is available in RV parks?

    Tesla doesn’t sell the correct 30 amp adapter for the plug type, and I’d like to be able to charge when only 30 amps is available in a park.
     
  2. brkaus

    brkaus Well-Known Member

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    #2 brkaus, Nov 14, 2019
    Last edited: Nov 14, 2019
    I don’t have my plug to compare for sure - but that’s a TT-30?

    I think the answer is NO. My understanding is the Tesla TT-30 to 14-50 connects the wires differently.

    if you search amazon, Home Depot, etc. you will find notes that some are for Tesla only and some are for RV only.

    I think the RV adapter connects the hot of the 120v to both hots of the 14-50. So the RV will still see 120v hot to neutral on both hots. But hot to hot will be 0v.

    I think the Tesla adapter puts the hot to one hot and the neutral to the other hot.
     
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  3. Lindamon

    Lindamon Member

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    I was afraid of that, kind of what I though too. Thanks!
     
  4. mba83

    mba83 Member

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    ^ that is correct, adapters are different.
     
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  5. ewoodrick

    ewoodrick Well-Known Member

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    That's a 120V plug. the 14-50 is a 240V plug, half the voltage = half the charging.

    You can get an adapter to charge off of the TT30 plug.
    No, not all campgrounds have 14-50, although all that allow bigger motorhomes do.

    But you are probably suffering from range anxiety. The number of people and locations that require campground charging is pretty close to 0%.
     
  6. Lindamon

    Lindamon Member

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    Thanks for your reply. No, not suffering range anxiety. I am very familiar with RV camping, we have done it for months at a time for many years now with both a 30 amp rig and now a 50 amp rig.

    But now we want to car camp using our X in some state campgrounds, as well as regular campgrounds, and state campgrounds often have no more than 30 amp service.

    I found an adapter on Amazon that should do the trick:

    https://www.amazon.com/gp/product/B07G2MT4T6/ref=ppx_od_dt_b_asin_title_s00?ie=UTF8&psc=1
     
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  7. brkaus

    brkaus Well-Known Member

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    Looks correct. Just don’t confuse them :)
     
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  8. brianman

    brianman Burrito Founder

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  9. Lindamon

    Lindamon Member

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  10. brianman

    brianman Burrito Founder

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    Probably. Look at where your adapters connect; it's easy to tell a Gen1 from a Gen2 by looking.
     
  11. Lindamon

    Lindamon Member

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    Yes I edited my post when I read the description, mine is Gen2, thanks!
     
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  12. ewoodrick

    ewoodrick Well-Known Member

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    While I'm not a fan of the adapter, since the car is going to try to trip the circuit, it is an option. I'd also think about the 5-20 adapter which should work great for weekend camping when you have time to charge .
     
  13. Lindamon

    Lindamon Member

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    Yes, you have to remember to set the amps to 24 with the Amazon one, so I am going with the EVSE adapter brianman suggested with the automatic settings. It’s pricier, but so is the car itself.

    I prefer not to use the 5-20, if there is one available on the post, we have other electronic devices, lights, etc that we use on the 5-20’s, but it’s for sure an option.
     
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  14. ajdelange

    ajdelange Banned

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    Yes. The car wants a ground (earth) and two "hots". The two hots go straight into a bridge so it doesn't matter if one of the "hots" is the neutral in a 120V system. In the adapter the flat pins on the TT-30 plug are wired to the two slots on the 14-50R adjacent to the earth (D-shaped or round) hole and the D-shaped hole is wired to the earth (bent or round as in your picture) pin on the TT-30. The slot on the opposite side of the 14-50R from the earth is not connected to anything. Lest someone will want to argue with me (and here someone probably will) on this I have ohmed it out.

    Now note that you must reduce the charging rate in the car to 24 A in order to comply with the spirit of the non-intermittent load requirements of the NEC if charging for more than 3 hours. If charging for less than that I suppose you could go to 30 but above 30 the campground breaker will trip. My TT-30 adapter (part of a collection of adapters I have never used) has a sticker on it warning the user to do this (set to 24 A).
     
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  15. eladts

    eladts Member

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    No, TT-30 to 14-50 mean for RV use will not work for EV charging. This adapters connects both hots of the 14-50 to the hot of the TT-30, so the voltage between them is 0.
     
  16. ajdelange

    ajdelange Banned

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    #16 ajdelange, Nov 15, 2019
    Last edited: Nov 15, 2019
    I wasn't wrong when I said someone would disagree even though I said that I ohmed it out and it wouldn't make any sense to sell an adapter that shorted the two hots. I have the piece on the bench in front of me. There is no connection between the two hots. It is as I described in #14 and it will, therefore, work.

    Why is common sense so rare?

    Well, actually, let's be more careful here. I am speaking of the TT-30 adapter that is sold specifically to allow charging Teslas i.e. as a Tesla accessory. Perhaps there are adapters that connect the two blades together for use when kluging a 240 V camper to a 120V plug. That would allow use of 120V appliances in the camper and disable any 240 V loads.

    I think the message is to ohm out any adpater you currently have. If the two hots (on the 14-50 side) are common you will not be able to use it.

    Note that there would be no danger were the camper adapter used to try to charge the Tesla but there would be potential danger of damage to RV 240V loads were the Tesla adapter used to connect an RV. So if you get a Telsa adapter be sure to mark it with bright red nail polish or something.
     
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  17. brkaus

    brkaus Well-Known Member

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    BTW - I would have purchased the TT-30 made specifically for the UMC that automatically sets the current had it been available back when I purchased my TT-30 to 14-50 adaptor.
     
  18. eladts

    eladts Member

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    Oh, I missed that the adapter is for EV use rather than for RV use. However, such EV adapters will not set the current correctly so it is much better to use the specific TT-30 to UMC adapter. The price difference is negligible compared to the risk of overloading the circuit by mistake.
     
  19. Rocky_H

    Rocky_H Well-Known Member

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    Yes, I do really love the new Gen2 adapters that EVSEadapters makes, and that is what I generally recommend to people to set the current properly. It's a cleaner look, has less total connections, and preserves the temperature sensor in the plug that the Gen2 adapters have.

    However, I also bought one of the old pigtail adapters @brkaus is talking about years ago that just converts a TT-30 plug to a 14-50 receptacle. Back then, Tesla was not selling any official plugs for 30A outlets, so we didn't have much choice and were having to adapt everything to 14-50 receptacles because that's what we had and EVSEadapters wasn't making the good stuff yet. So, the solution we have now that does set the current properly is that I have cut off the neutral pin of my 14-30 adapter with a hacksaw. As @ajdelange has pointed out, the neutral pin on these 14-XX adapters is disconnected internally and not used for anything, so it doesn't matter if it's cut off. And then that lets me plug my 14-30 into that TT-30 adapter cord, and it will set the current to 24A automatically, without my having to remember to do it on the car's screen.
     

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