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How can I use a NEMA 10-50 at a Bed and Breakfast

Discussion in 'Model S: Battery & Charging' started by GasDoc, Jun 17, 2013.

  1. GasDoc

    GasDoc Member

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    I found out that the B&B I want to stay at for an upcoming wedding has a NEMA 10-50 on a 30amp breaker.

    Can I buy/build an adapter to plug a NEMA 14-50 into this? I'll dial my charging down to 30amps.

    Here is a picture:
    DSC01640.JPG
     
  2. FlasherZ

    FlasherZ Sig Model S + Sig Model X + Model 3 Resv

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    See the FAQ, specifically the question "I HAVE AN OLD-STYLE ELECTRIC RANGE OUTLET AVAILABLE (NEMA 10-50), CAN I MAKE AN ADAPTOR CORD TO THE TESLA’S 14-50 UMC PLUG FOR IT?"
     
  3. TI Sailor

    TI Sailor Member

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  4. Tacket

    Tacket Member

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    I purchased the universal 10 adapter and its high quality. I have not tested it yet as my car does not arrive until Sunday. I got that as well as their 14-30 adapter.
     
  5. Cosmacelf

    Cosmacelf Active Member

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    The EVSEadapters.com site looks like your best bet. You can make these yourself as well (check out http://cosmacelf.net/Home%20Made%20Adapters.pdf - it'll be similar to the 10-30 adapter). PLEASE dial down the amps to 24 amps, not 30! For any continuous electrical use longer than something like 3 hours, you are supposed to only draw 80% of the breaker/wire rating. Considering the wiring is already dodgy since they are using a 30A breaker on a 50A receptacle (why?), I wouldn't push it past 24 amps just to be on the safe side anyways. 24 amps should be fine for overnight charging.
     
  6. jerry33

    jerry33 S85 - VIN:P05130 - 3/2/13

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    And for the first couple of charges, check things after an hour or so and make sure they are not getting hot. (warm is okay, but not hot).
     
  7. dhrivnak

    dhrivnak Active Member

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    I have made such an adapter ($20 if you want it) and if you have basic wiring skills it is not difficult. But be warned you may not want to charge at 30 amps and will likely need to setp down one level. If I recall that circuit normally has a 30 amp breaker. If you charge the car at 100% capacity it is likely to trip, maybe not intially but running at 100% is right on the line.

    So when I did this at my son's apartment I charged at 24 amps which was enough for me to still have a full charge in the morning.
     
  8. FlasherZ

    FlasherZ Sig Model S + Sig Model X + Model 3 Resv

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    Yes, 24A is the maximum you should pull through this for sustained periods of time, since the breaker is rated at 30A and the wiring is unknown. Doing what they did is legal, until you connect a 40A load to it (then it violates code). You might want to advise them to upgrade the wiring to #8 and swap it out for a 14-50 so that anyone might use it.
     
  9. Seattle

    Seattle Member

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    evseadapter.com tt30 adapter - can it really deliver 30 amps 120volts?

    The tt-30 outlets are problematic and a very desirable adapter if you get the right one. The outlets are 120v but 30 amp instead of a normal 15 amp 120v outlet (normal outlets are called nema 5-15, 15 for 15 amps). Since tt-30 are double the amperage, they can charge your car twice as fast (about 6 miles of range/hour vs 3), plus they are ubiquitous in camping areas.

    There are some tt-30 adapters that have the regular 5-15 outlet and the tesla will only charge those as a regular outlet, 3 miles of range/hour of charging b/c the tesla treats those adapters as 15 amps. But the tt-30 adapter at evseadapters.com is the first commercial one I've seen that should charge at the full amperage (since it connects to the 14-50 tesla adapter, and thus should be able to charge at 6 m/range/hour). You'll have to tell the tesla to take only 24 amps of charge, but still. I've learned from reading these groups that you can only charge continuously at 80% of max amperage, so 80% of 30=24amps. A normal outlet is 80% x 15 = 12 amps.

    Also for reasons too complex to describe here you need special wiring for the tesla to use a tt-30 but this adapter says it has the "special", "different" wiring.

    I hope flasherZ or cosmacelf can weigh in on this tt30 evseadapter. I want to buy a tt-30 that delivers the full power of the outlet.
     
  10. Cosmacelf

    Cosmacelf Active Member

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    Oh wow, evseadapters.com must have added that very recently, I didn't see a TT-30 adapter there a few days ago. The problem with a regular TT-30 adapter is that it only supplies 120 volts, which is all a TT-30 can supply. Tesla's charging system has a limitation in that it only draws a maximum of 20 amps when connected to a 120 volt power source. With a TT-30, you would be safe drawing 24 amps, but the Tesla will only draw 20 amps. So that evseadapters.com TT-30 adapter is nice, and I'm sure they have wired it for correct operation with the Tesla, but you won't get a full 24 amps from it, unless Tesla one day removes what is probably a software limitation.

    If you have access to more than one TT-30 outlet, there is likely a way around this limitation. What you would build is a 2x120v to 240 volt combiner box. IF the two TT-30 outlets are on different breaker box legs, then they can be combined for 240v at 24 amps charging, or 14 or more miles per hour of rated charging. Building such a box is a bit of a project involving relays (for shock prevention, mandatory) and 30 amp wiring, but it could be done.
     
  11. roblab

    roblab Active Member

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    As to building an adapter for the 10-50 to 14-50, I have done that, used it, and it works well. Built it myself. Easy to do, or stop by and borrow mine while you are headed to Calistoga. Plug vehicle connector into 14-50, plug 10-50 into welder outlet, dial down to 24 amps, and go.

    I wonder if the B&B owner has #6 wire to his plug, cause if he does, just buy him a new 50 amp circuit breaker and charge at 40 amps.
     
  12. GasDoc

    GasDoc Member

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    Calistoga RV park is close enough to walk to many B&B's and the main street area. They said the charge was $10 for overnight parking and use of a NEMA 14-50.
     
  13. FlasherZ

    FlasherZ Sig Model S + Sig Model X + Model 3 Resv

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    If it's simply THHN wire in that conduit, #8 is sufficient for 50A. #6 is only required if you have only a 60 degC rating -- for example, if you use NM-B/Romex.
     

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