charging at vacation/rental house with only 20 amps (at 240vac) available

[RustyShacklefo]

Newbie here. Nissan Leaf owner, with a Model Y LR on the way (can't wait !). I already have a hardwired 32 amp J1772 Level-2 EVSE installed at home, so I'm good to go there - my understanding being that the car comes with an adapter allowing Level-2 charging from a J1772 EVSE.

We also have a vacation rental house. For various reasons, I only have 20 amps (continuous) to work with. That's because there is a subpanel close to the parking area and that's all it has to spare. The main panel doesn't have room, and it's too far. So 20 amps continuous (25 amps breaker) it is. So what's my best strategy ?

I'm leaning towards installed an Emporia adjustable J1772 standard unit (Emporia EV Charger Black | Energy Star | UL Listed | 48 Amp | 24' Cable | 22) wired with 10awg THWN to a 25 amp breaker in the subpanel. The Emporia allows you to dial in virtually any charging amperage, including 20 amps. If I ever decide to install heavier wiring to a space I make available in the main panel, I don't need a new EVSE. Being J1772, renters will be able to use it, regardless of what car they have. It's pretty cheap too, at $399, and has some cloud connectivity that I may or may not use.

Another option is the Tesla hardwired unit. I understand there are adapters that allow charing non-Tesla vehicles (with J1772-compatible ports) from a Tesla EVSE, but I've heard most of them are junk; and I wouldn't imagine that many non-Tesla renters would have one, whereas all Tesla owners presumably have the free-with-car adapter. Also, 20 amps is not an option with the Tesla unit, it'd have to be 16 amps (the next higher amperage choice being 24 amps IIRC).

Finally, I could install an outlet and use the "mobile connector" cord. Even though it no longer comes free with the car (as I understand it), it's still a lot cheaper than a hardwired EVSE like the Emporia. And it'd be nice to have on the road. The question would be, what outlet to install ? I originally thought of a 14-50, because the Tesla cord, and the one for the Leaf (and most other brands, I suspect), use that on their mobile cords. But this thread: Nema 14-50 on 20A Breaker? suggests it's not code-compliant to put a 14-50 outlet on a 20/25-amp circuit. I wonder also, does the adapter somehow signal to the logic in the mobile cord which adapter it is (with buttons that it depresses when you plug it in, or something similar) or does the logic simply discern the amperage available by checking for voltage drop ? If the former, then that's another reason to not to do a 14-50 outlet, if the EVSE will try to pull 40 amps from my circuit (tripping the breaker for sure). I guess the right thing is to install a 6-20 outlet and buy the 6-20 adapter for the Tesla cord. But then probably most renters will be completely unable to use it (I don't think many other charging cords have a 6-20 plug). Nor will the Leaf be able to use it. So I'm not crazy about the 6-20 outlet.

So it's a conundrum. Thoughts ? TIA !

 

[RustyShacklefo]

As far as being able to charge non-Tesla from Tesla EVSE, folks on other forum report good results with this: Great deal on a Tesla-to-J1772 adapter (for charging...

Stiil, if I go hardwired, pretty sure I'll go with the Emporia, as it allows selecting 20 amps as charging current (and Tesla does not). Emporia is really not much more expensive than Tesla mobile connector, plus a NEMA adapter, plus a weatherproof box+outlet+cover, plus a GFCI double-pole breaker. So it really comes down to whether I will end up buying a mobile connector anyhow (apparently it no longer comes free with car in USA).

 

[Acps110]

For your rental house, J1772 would be preferred due to every other EV using it besides Tesla.

Hardwired is the best choice, it removes a point of failure (an outlet) from the chain. An outlet can heat up and melt; much more difficult to melt a hardwired connection.

For your question about the Tesla Mobile Connector and its adapters for various outlets… Each adapter has a resistor in it that tells the Mobile Connector what it is plugged into and what the corresponding 80% output is. The Mobile Connector doesn’t care about the voltage, you can supply it with anything from 120-208-240 volts. It only cares about the allowed amp draw on the circuit it is connected to.

 

[3sr+buyer]

If you go for plugin solution, the obvious outlet would be 6-20 (since there are no -25 outlets, just -20 or -30), but EVSEs for that would be 16A.

To use 20A on a 25A circuit, a hardwired EVSE that does 20A would get the highest charge rate without overloading it.

There are also plugin 20A EVSEs for 14-30, but that risks someone later forgetting that the circuit is 25A instead of 30A and plugging a 24A EVSE (such as a Tesla Mobile Connector with a 14-30 plug) into it.

Don't put a 14-50 outlet there for the same reason. Actually, that is even more tempting to make a mistake, since some other EVs come with non-adjustable 32A 14-50 EVSEs that drivers may be tempted to use if they see a 14-50 outlet (with or without a 20A EVSE plugged into it).

 

[RustyShacklefo]

If you go for plugin solution, the obvious outlet would be 6-20 (since there are no -25 outlets, just -20 or -30), but EVSEs for that would be 16A.

To use 20A on a 25A circuit, a hardwired EVSE that does 20A would get the highest charge rate without overloading it.

There are also plugin 20A EVSEs for 14-30, but that risks someone later forgetting that the circuit is 25A instead of 30A and plugging a 24A EVSE (such as a Tesla Mobile Connector with a 14-30 plug) into it.

Don't put a 14-50 outlet there for the same reason. Actually, that is even more tempting to make a mistake, since some other EVs come with non-adjustable 32A 14-50 EVSEs that drivers may be tempted to use if they see a 14-50 outlet (with or without a 20A EVSE plugged into it).

Great summary of my situation. I think it's pretty clear that the hardwired Emppria is the way to go. The only rub is that if I decide I need a Mobile Connector, it's add'l cost (when I could've used it as the charger, with the caveats you mention). But still chump change in the scheme of things.

One factor brought up elsewhere is the potential for vanadalism, or careless usage, with the hard-wired unit. It seems to be a very low crime area though; the basement door did not even have a working lock when we bought the place !

 

[3sr+buyer]

One factor brought up elsewhere is the potential for vanadalism, or careless usage, with the hard-wired unit. It seems to be a very low crime area though; the basement door did not even have a working lock when we bought the place !

If it is outside of a vacation rental, there may be the possibility of mooching by those who are not residents or renters.

 

[brkaus]

You might consider a switch inside the house if possible. That would reduce the other theft.

I would do the j1772 if it’s a rental property. No one is going to have the 6-20 adapter. Not many will have the Tesla to j1772 and if you provide it there is a chance it will walk away or be damaged.