RV adapter

Discussion in 'Hyundai Kona Electric' started by R P, Jul 20, 2019.

  1. Yes, if you didn't adjust your L2 charge current on the car. But you can adjust that lower, so you draw less power.
  2. BlueKonaEV

    BlueKonaEV Well-Known Member

    True.. Didn't think of that..
  3. However, just remember that 3000 watts is only 25 amps at 120V (80% of breaker). That's what Fastnf said he was drawing at the max setting for L2, post #7. So sounds like you can leave it on the max setting, same as 240V which will of course then draw higher kVs.
  4. electriceddy

    electriceddy Well-Known Member

    I would like to test the 3 L2 charge rate reductions on that screen to see the actual current with my RMS clamp on meter , some other time I will post.
  5. Since you can't establish continuity because of the relay, how exactly did you confirm which 14-50 hot prong (X or Y) to connect the RV neutral? I would assume Ln2 on your EVSE would be the same as on mine to conform to the EV J-1772 standard.
  6. In post # 9 I posted a picture of the inside of my GE DuraSation level charger. This charger is in a Hoffman Nema 4 box that is easily opened by removing the two screw on the hinged cover. You can see in the picture that all of the main wires are labeled. The two black boxes on the right side of the board are the relays. I checked continuity up to the relay and then checked it after the relay to verify the which was line 1 and which was line 2. In addition the circuit board at the relays is labeled as well. So in my case it was easy to confirm. It may not be easy with other brands of chargers.

    I have read a number of Tesla post regarding their use of TT-30 adapters and noted that Tesla chargers wouldn't work if the lines were reversed.

    I am not advocating people try this I am just providing information that it can be done. In my case I have enough experience with electronics that I was willing to try it, with the full knowledge that if I screwed up I would be buying a new charger. Fortunately it worked out well for me and the charger.

    I have re-posted the pictures here

    IMG_2642.JPG IMG_2630.JPG
    Bugblndr likes this.
  7. I

    I wouldn't assume that mine is wired up the same on L2 as other chargers. The reason I say this is that when using 240 volt both legs are hot so it doesn't matter which leg goes to L2. It only when using 120 volt that N needs to be connected to L2/N. So if the charger is designed as a 120/240 volt charger then it will have N to L2/N but if it is a 240 volt only charger its a 50/50 chance. That's why some EV adapters don't always work. There may be a standard some where that says that X or Y goes to L2/N but I am not aware of it.

    If there are any IEEE engineers out there who know of such standard let us know.
  8. Yes, I did see that. But my EVSE is sealed and can't be opened (that I know of). So the only thing to try with mine is wiring the adapter same as yours. IE, which of the hot prongs (x or y) did you put the RV neutral?

    I am looking at maybe buying a dogbone RV adapter, cutting the cord and rewiring to get the neutral on the appropriate hot prong. Being in Canada, can't get the Tesla adapter locally, but I can get a cheap TT-30P to 14-50R dogbone adapter.

    Just a thought at this time. I may just wait until I go across the border for other reasons, and order the Tesla one. Will see..., no big rush at this time. Not planning any trips up north for a while (where I would need it).
  9. My charger came without a plug as it was designed to either be hard wired or plug wired. I purchased a 40amp 6 gauge range plug and wired it to be portable. I could have put either x or y on line 2 and it wouldn't have mattered. Even now I could switch line x and y and make the same switch in the 14-50 adapter plug end and it would work. So it doesn't matter if line x is neutral or line y is neutral as long as the chosen line for neutral connect to the line for L2/N prong on the J-1772. Note that the neutral Position on the TT-30 plug is fixed and should always remain in the NEMA required Location.

    Most dog bones are injection molded plugs which can't be taken apart so you would probably need a new 14-50 receptacle end or I suppose you could just cut the wires and crimp or solder them and shrink rap correctly for the EV adapter. I wanted a cleaner look so I bought a TT-30 plug for $10 and a $15 14-50 receptacle end and used an 8 gauge 3 wire cable I had from an old welder. Below is a link to the plugs and a picture of the finished adapter. Both plugs have sharpie marks showing the hot and neutral locations I used.

    Last edited: Sep 11, 2019
  10. Thanks, the additional pics and explanation are very helpful. But I don't understand you saying the neutral could work on either x or y. Does that position not correspond directly to the L2/N prong on the J-1772?

    And aren't L2/N positions on an EVSE or on an EV (like the Kona) part of the J-1772 standard?
  11. L2/N's position on the car end is fixed as part of the SAE J-1772 standard which set it as the neutral side for 120 volt operation. The problem arises in the adapter. Since the 14-50 is being used in a non standard configuration. Standard configuration is X and Y both hot. To use it with the TT-30 plug one of the hots need to be hooked to neutral. It is at this point where the choice is made and the confusion arises. If you connect the Y leg to neutral, then the Y legs gets connected to the L2/N plug. The X leg then get the hot lead and goes to the 1 lead on the J-1772, and all is good. But you could have just as easily connected the X leg to the neutral side of the TT-30. In that case the X leg would be connected to the L2/N side of the J-1772 and the Y leg would go to the hot side of the TT-30 and on to the 1 lead of the J-1772. In both cases the neural from the TT-30 end up at the L2/N side. There in is the the problem, either x or Y can be the neutral side.
  12. OK, I think I get what you are saying. The J-1772 plug side is standard. But the EVSE could use either x or y on the 14-50 to go to L2/N. With 240 it doesn't matter, but with 120 it does, because it needs that neutral. Is that correct?
  13. Yes that's it exactly.
  14. Thanks, and sorry for being a little dense. But I learned a lot...

    So getting back to the Tesla RV adapter. If I try it, and my EVSE happens to have the L2/N on the wrong 14-50 prong, will it just not work, or could there be damage to my EVSE or car?
  15. electriceddy

    electriceddy Well-Known Member

    What make/model EVSE do you want to try this with?

  16. I don't know what the result would be if wired backwards. I would hope Hyundai has built in protection for the car as it is not uncommon for amateurs replacing a home socket to install the lines reversed.

    I have not seen any one on the Tesla sites mention damage just that the leads needed to be reversed. you might try a search for RV 30amp Tesla adapters and read though there comments. Hear is one such link https://teslamotorsclub.com/tmc/threads/rv-tt-30-to-ev-14-50-adapter.96199/
  17. There are several company's that sell EVSE components . About half the cost of an EVSE is the cable and the Plug. I have seen EVSE circuit boards from $50 -100. So if had had a problem I had just planed on replacing the circuit board in mine.

    Here is a link to a site that show all of the circuity on an open source EVSE circuit board. It has a ground fault circuit which would be a protection, but again I don't know what protections your particular EVSE has on its circuit board.

  18. electriceddy

    electriceddy Well-Known Member

    Looks like it may work but who knows the schematic - why not just email Morec (c/w model #)and ask first?
  19. I did actually send him an email, but got no reply. I also spoke to the SimplyWork guy and he says his works at 110V and 12A (same as the granny cable) with an adapter, but didn't know anything about the 30A RV adapters and being able to charge at higher kVs. Seems like these guys just sell them and don't know much else about the specs or schematics. And the little instruction book that comes in the box tells you nothing. Doesn't even name the brand, looks more like a generic booklet that could apply to many EVSEs.

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