NEMA 14-50 with 120v

[AudubonB]

I feel like we're in the Twilight Zone here. Normal laws of physics aren't coming into play...

If I recall various nuggets from the OP correctly, we have:

* a 50A 120V line coming into each house in a complex of vacation homes

* main panel is a few hundred yards away (can you say "120V line loss"?)

* one of these houses - the OP's - that has:

* an electric water heater
* an electric 20-jet 5-seater hot tub
* a soon-to-be electric charger for a 60 or 85kWh battery-packed car
* some solar panels that are...what?...throwing electrons back up that 50A 120V line?

All in all, this I gotta see. I'll bring the marshmallows.

 

[islandbayy]

I feel like we're in the Twilight Zone here. Normal laws of physics aren't coming into play...

If I recall various nuggets from the OP correctly, we have:

* a 50A 120V line coming into each house in a complex of vacation homes

* main panel is a few hundred yards away (can you say "120V line loss"?)

* one of these houses - the OP's - that has:

* an electric water heater
* an electric 20-jet 5-seater hot tub
* a soon-to-be electric charger for a 60 or 85kWh battery-packed car
* some solar panels that are...what?...throwing electrons back up that 50A 120V line?

All in all, this I gotta see. I'll bring the marshmallows.

Forget the Marshmallows, I'll bring the steaks & ribs. Bubba's Throwin a Bar-Be-Q

 

[brianman]

Afaik, there is no way to charge a Model S with DC.

Superchargers.

 

[Cosmacelf]

Superchargers.

I meant no way for a person with a random DC source to fill up a Model S.

 

[AndreyATC]

I feel like we're in the Twilight Zone here. Normal laws of physics aren't coming into play...

If I recall various nuggets from the OP correctly, we have:

* a 50A 120V line coming into each house in a complex of vacation homes

* main panel is a few hundred yards away (can you say "120V line loss"?)

* one of these houses - the OP's - that has:

* an electric water heater
* an electric 20-jet 5-seater hot tub
* a soon-to-be electric charger for a 60 or 85kWh battery-packed car
* some solar panels that are...what?...throwing electrons back up that 50A 120V line?

All in all, this I gotta see. I'll bring the marshmallows.

Haha
It does require some managing with 50A
I'm pretty much maxed out there, but not all is listed
I forgot to mention electric golf cart that is charging with 15A

Now,
If we really want to count numbers it's not as terrible as it seems
1. Spa is only running it's heater 4 months a year, the rest of the time it's heated with solar
2. Golf card is 99% of the time is charged by 3 solar panels, unless it's dead in the winter and i pull on-board charger 2-3 time a year
3. Electric heater is my main "problem", however, it's almost in stand by mode overnight, while Tesla is charging

 

[aaronw]

Since the neutral on the NEMA 14-50 outlet is not hooked up it won't work. You're better off just installing a regular 110v 20A outlet, i.e. Leviton 20 Amp Duplex Outlet - White-R52-05352-0WS at The Home Depot

Tesla sells a 20A adapter for the UMC.

 

[AndreyATC]

Since the neutral on the NEMA 14-50 outlet is not hooked up it won't work. You're better off just installing a regular 110v 20A outlet, i.e. Leviton 20 Amp Duplex Outlet - White-R52-05352-0WS at The Home Depot

Tesla sells a 20A adapter for the UMC.

This was original idea and it's not going to give me 20A, it's 16A real draw
Just like 15A gives you 12A , aka 80%

 

[efxjim]

Build a dedicated charger (open evse ) for the Tesla and interrupt the pilot line with a relay when your heat or water heater comes on. Then all appliances can remain on.

 

[AndreyATC]

Build a dedicated charger (open evse ) for the Tesla and interrupt the pilot line with a relay when your heat or water heater comes on. Then all appliances can remain on.

I like the idea
Definitely beats running outside to the street post to reset breaker
Is it easy enough to implement?
Electrician will be running brand new, dedicated line from the meter to install NEMA TT-30

 

[mitch672]

I like the idea
Definitely beats running outside to the street post to reset breaker
Is it easy enough to implement?
Electrician will be running brand new, dedicated line from the meter to install NEMA TT-30

You'll need a 2 wire low voltage wire out to the OpenEVSE, you would need to have relays installed on the appliances, with dry contact closure output, so you can interrupt the pilot signal when they are on. I did a similar thing with my central air conditioning compressors and my generator, I ran wires to the low voltage controls on them, when AC power fails from the utility, I "open" the low voltage controls to the compressors, so they cannot run, if the power is out from the utility (since my generator is auto start, and not large enough to run the compressors). You would use the same concept, when high current devices are "on", open the J-1772 pilot signal on the OpenEVSE, the car will stop charging temporarily, when the high current appliances are off, close the relay, vehicle charging resumes.

 

[Cottonwood]

You'll need a 2 wire low voltage wire out to the OpenEVSE, you would need to have relays installed on the appliances, with dry contact closure output, so you can interrupt the pilot signal when they are on. I did a similar thing with my central air conditioning compressors and my generator, I ran wires to the low voltage controls on them, when AC power fails from the utility, I "open" the low voltage controls to the compressors, so they cannot run, if the power is out from the utility (since my generator is auto start, and not large enough to run the compressors). You would use the same concept, when high current devices are "on", open the J-1772 pilot signal on the OpenEVSE, the car will stop charging temporarily, when the high current appliances are off, close the relay, vehicle charging resumes.

Or you could use something like this, AC Current Switch/DC Current Switch/Current Switches/Current Transformer/Current Sensing Switches. A current switch like this "Combines a current transformer, signal conditioner and limit alarm into a single package."

A few different companies make these, and I have even found them on E-bay.

If you really want to get carried away, you could use a 120V to 240V transformer and modulate the J1772 pilot with the available current. On the other hand, I think that I would keep it simple, stay with the TT-30 and adapter, and turn down the current in the MS whenever you think that there is a risk of going over 40A total in the cottage... :wink:

 

[FlasherZ]

Most RV adapters will provide 120V between each Line connection and Neutral, but Zero Volts between the two Line connection. The Tesla wants to see 120V between the two Line connections, which is what the Tesla specific adapter will do. However, using the Tesla specific adapter for an RV will provide Zero Volts to one of the Lines, and not power half of the connections in the RV.

Actually, using a Tesla adapter that has disconnected the neutral on the 14-50 will cause a pretty serious problem for an RV that tries using it, because it will float the neutral and give 120V to devices that expect 240V. So 240V appliances will get severe undervoltage, and with neutral floating, it would give wildly variable voltage to 120V devices, depending upon what is turned on within the RV.

Best idea - mark it "TESLA CHARGING ONLY - WILL RESULT IN DAMAGE TO NON-TESLA DEVICES" or something similar.

See the FAQ (click here) for more information.