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Y connector to combine 2 campsite 14-50s?
- Thread starter Ceilidh
- Start date
Tesla will be squarely focused on SuperChargers for those who need "mobile" power.
Sounds like Peter (bluetinc) has a design that does all the necessary safety monitoring of power leg alignment, circuit current load balancing, etc., so someone may be willing to build it for you (or it sounds like a great business idea -- maybe soflauthor can buy the rights to it for Teslacessories
)The issue here for productization is usability, really. There are so many ways to arrange power for RV parks that there's no guarantee it will work, and how can you make the thing simple so my mother could use it?
Someone here might build one for you.
Hey All,
I saw this tread and figured I'd toss up some pics before I manage to get a writeup up on the web site. The short version is that it is a custom EVSE that I designed and built. It has a bunch of processing and safety checks that get preformed on the two inputs to see what it can do with the inputs, takes care of communicating with the car etc, and continues safety checks during charging. I've found all of the RV parks to be very happy to let me use two 14-50R's, and all but one have been usable for my system. Here are a few pics of one of the easier hookups with two 14-50R's on the same post
1) What web site will you be posting this to?
2) I too would be extremely interested in a specific schematic.
3) How much did it cost you total for parts?
4) How much does it weigh?
For some reason, every time someone posts about actually using one of these that they built, they never post the plans so others can recreate it. I have seen at least one other person's post about it that left out the plans and so I went to an Open EVSE google group to ask, where I got nearly flamed off the board for asking about "widowmaker" wiring and was told it cannot be done, and if done it will kill me and burn down the RV park.
Would be nice to change this experience as researching how to do this with a modicum of safety is extremely challenging.
Thanks for posting the pics to prove it can and has been done... don't see any flames in the photo so it would seem the Google group has been proven wrong. Feeling slightly vindicated here.
Cheers
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The roadster person who did this many moons ago mentioned that they made their own box to link the 2 RV plugs, then fed it into a standard roadster wall charger from clipper creek in the way that it would usually be wired from inside the wall in your garage. Had to lug around that huge heavy box in the car.
I would imagine you could do the same thing with the HPWC as it stands, and it is much smaller and lighter than the clipper creek roadster charger.
This device pictured seems much more compact than two separate boxes and would likely be cheaper, but we will have to wait for details from the designer (posting soon we hope
)Cheers
Hey All,
I saw this tread and figured I'd toss up some pics before I manage to get a writeup up on the web site. The short version is that it is a custom EVSE that I designed and built. It has a bunch of processing and safety checks that get preformed on the two inputs to see what it can do with the inputs, takes care of communicating with the car etc, and continues safety checks during charging. I've found all of the RV parks to be very happy to let me use two 14-50R's, and all but one have been usable for my system. Here are a few pics of one of the easier hookups with two 14-50R's on the same post
Peter
View attachment 13923View attachment 13924View attachment 13925
I can imagine many people interested in buying this!!!!!!!!!
mitch672
Active Member
Do you see all of the relays in the box? They must each be capable of switching 50Amps. There must be enough of them to do an "X" cross, if for example the legs from each 14-50 are opposite. Also, if one of the breakers trips, the EVSE must be monitoring that and immediately drop the pilot signal from 80A to 40A, or the remaining 14-50 circuit breaker will trip when the Model S charger draws 80A from it (or, if it fails to trip, that is the fire hazard we mentioned to you on that "OpenEVSE google group").
Also when one of the 14-50s is unplugged it must present a "dead front" meaning it has no live exposed voltage on it.
Many things can be made to work, that doesn't mean it's a great idea to do so. This falls smack into this category. As for costs, to start with you have a 75A J-1772 cable, that's about $240, then 240V 50A relays, he has 6 pictured, I imagine they run $30-40 each, then the large NEMA enclosure he is using is about $120 (I am using the same one on my 75A OpenEVSE), he has some kind of microcontoller with Current Transformers (minimum 2 are needed), then there are the 6/3 or 6/4 line cords with connectors, inlets to the box, wiring, etc. this box is at least $700-800
I would like to see the detailed schematic, it is possible to make a safe device, it's just difficult thinking of and handling all of the possible failure/safety issues.
Also when one of the 14-50s is unplugged it must present a "dead front" meaning it has no live exposed voltage on it.
Many things can be made to work, that doesn't mean it's a great idea to do so. This falls smack into this category. As for costs, to start with you have a 75A J-1772 cable, that's about $240, then 240V 50A relays, he has 6 pictured, I imagine they run $30-40 each, then the large NEMA enclosure he is using is about $120 (I am using the same one on my 75A OpenEVSE), he has some kind of microcontoller with Current Transformers (minimum 2 are needed), then there are the 6/3 or 6/4 line cords with connectors, inlets to the box, wiring, etc. this box is at least $700-800
I would like to see the detailed schematic, it is possible to make a safe device, it's just difficult thinking of and handling all of the possible failure/safety issues.
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If I had dual chargers I would be clamoring for drawings or a price! This looks great!
Glad to see you chime in Mitch.
Wish someone at the group had a thoughtful response to me like this one you just posted since when I asked about this there I was specific in my intent to do it as safely as possible and got responses that were somewhat less friendly and flippantly dismissive.
Would love to have the expertise of that group contributing to the design ideas in a more thoughtful manner.
Cheers.
Wish someone at the group had a thoughtful response to me like this one you just posted since when I asked about this there I was specific in my intent to do it as safely as possible and got responses that were somewhat less friendly and flippantly dismissive.
Would love to have the expertise of that group contributing to the design ideas in a more thoughtful manner.
Cheers.
Don't forget checking to make sure you don't have something like a 208Y/120 setup which would try to align out-of-phase legs, or monitoring the current across the multiple inputs to make sure you didn't end up with one too far out of balance, etc.
It should be noted that the NEC expressly forbids this type of paralleling for these loads.
Kipernicus
Model S Res#P1440
mitch672
Active Member
This check would be done on the "parallel" checking, the legs from each 14-50 can only be joined if they are at the same potential (no voltage between them). This could have been the one case he mentioned where his device didn't work. This device is mainly for single phase 120/240 service, 120/208, if 2 of 3 phases are used, and split up 1&2, and 2&3 (for example) on the same pedestal opposite drops, would not work. The safety check monitoring the voltage on each leg would catch this... You could still charge with 1 of the 14-50s at 40A though.
mitch672
Active Member
Nope. We just had "charge" timers added to it this past week, using an i2c date chip, it's almost out of code space at this point, the little $3 ATMEL (Arduino) chip used only has 32K. I think this would require a processor with more inputs and more memory, perhaps the "mega" version with 256k, or even a "Raspberry Pi" (they run Linux and have 512MB of RAM, and boot of SD cards, they also have i2c buss, SPI buss, serial port, ethernet interface, 2 USB ports, HDMI or composite video and some controllable I/O bits), all that for $35: FAQs | Raspberry Pi
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