Charging at Hotels

[ecarfan]

This is better than through the car window!
https://www.connectorprotector.com/

I the resting product. That web page says it protects your charging cable "from theft" (I agree) or "from being unplugged" (I don't see how it does that).

 

[Lloyd]

It prevents from being unplugged for those that don't lock the port, and in the sense that if you can't use the cable by being locked under your wheel it defeats the purpose of unplugging.

Good point! Perhaps I should change the site in that regard!,

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I had a wonderful stay at the Green Valley Resort, Las Vegas. They have a 14-50 adjacent to the front valet. I was the only one using it the entire weekend.

 

[hcsharp]

...In the morning I had time to check the room's Quick220 possibilities. Unlike some other motels I have tried, this one had accessible outlets for both the TV and refrigerator. My Quick220 detection meter verified that they happened to be on separate phases:

View attachment 43572

This meant I could have charged the car through the Quick220 at 12A for several hours while simultaneously running the A/C on its own 6-20r, but the night before I was very happy to have found a working solution, I was too tired to try this one, and I didn't need the extra charge time.

I doubt if the Quick220 solution would have worked. I wish you had tried it just to find out. Almost all hotels are on three phase as this one was. That means the 110v outlets are 120 deg out of phase with each other. They have to be 180 deg out of phase for this to work.

 

[Cottonwood]

I doubt if the Quick220 solution would have worked. I wish you had tried it just to find out. Almost all hotels are on three phase as this one was. That means the 110v outlets are 120 deg out of phase with each other. They have to be 180 deg out of phase for this to work.

Actually if the 120V outlets are not on GFCI''s and are not on the same phase, the with 3-Phase circuitry, then it will work, and as you say, they will be 120˚ apart, but that will still give you 208V! (2*cos(30)*120V=208V or sqrt(3)*120V=208V)

 

[hcsharp]

Actually if the 120V outlets are not on GFCI''s and are not on the same phase, the with 3-Phase circuitry, then it will work, and as you say, they will be 120˚ apart, but that will still give you 208V! (2*cos(30)*120V=208V or sqrt(3)*120V=208V)

The North American Model S charging system (and all Roadsters) will only initiate a charge if the phases are exactly 180 deg apart. It has to have a symmetrical wave form.

 

[miimura]

The North American Model S charging system (and all Roadsters) will only initiate a charge if the phases are exactly 180 deg apart. It has to have a symmetrical wave form.

I don't see how it's possible that this is true. That would mean that the cars would not charge on ANY 208VAC EVSE because those are all 3 phase 208Y/120V. There is no neutral and the difference between L1 and L2 has a sinusoidal waveform, so it's all good.

 

[mknox]

The North American Model S charging system (and all Roadsters) will only initiate a charge if the phases are exactly 180 deg apart. It has to have a symmetrical wave form.

Nope. There are J1772 stations and NEMA 14-50's etc. all over the place connected to two phases and neutral supplying 120/208 volts. Teslas will charge just fine from them. I do it all the time.

 

[hcsharp]

I don't see how it's possible that this is true. That would mean that the cars would not charge on ANY 208VAC EVSE because those are all 3 phase 208Y/120V. There is no neutral and the difference between L1 and L2 has a sinusoidal waveform, so it's all good.

Nope. There are J1772 stations and NEMA 14-50's etc. all over the place connected to two phases and neutral supplying 120/208 volts. Teslas will charge just fine from them. I do it all the time.

My second post is correct (the one you quoted). It won't charge unless the wave form is symmetrical. I also charge at 3 phase locations, usually at a disappointing 200v after it drops. My first post, the one you probably meant to respond to, is not correct because you can get 208v sinusoidal from two 120v outlets (120v x sqrt(3) = 208) if you are careful to combine them without the neutral. It would have been interesting to see if his combiner box would have worked. I have a combiner that I made myself but it's never worked at a hotel because the outlets were all on the same phase.

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There was an experiment performed at a hotel using 2 J1772 chargers on the forum somewhere. They were each 208v so naturally they were 120 deg out of phase. The experiment was an attempt to charge at 60A from two 30A stations. It would have worked if the building had been wired for split phase 240v. I've successfully done this at a campground using 2 NEMA 14-50 outlets - I did 70A. I did it once to see if it would work, but have never done it on a road trip because all the cables and large combiner box with two breakers is just too bulky to be worth it.

 

[Cottonwood]

My second post is correct (the one you quoted). It won't charge unless the wave form is symmetrical. I also charge at 3 phase locations, usually at a disappointing 200v after it drops. My first post, the one you probably meant to respond to, is not correct because you can get 208v sinusoidal from two 120v outlets (120v x sqrt(3) = 208) if you are careful to combine them without the neutral. It would have been interesting to see if his combiner box would have worked. I have a combiner that I made myself but it's never worked at a hotel because the outlets were all on the same phase.

I have used the Quick 220 Systems: Voltage Converters and they just throw away the neutral and use two line/hot sides and ground for the output. Quick 220 Systems: 20 Ampere Straight Blade Outlet is the one I have and it has a 6-20 output, which seems very reasonable. The big problem with these boxes is caused by how they work. All of the current passes through the two line/hot wires, and nothing is returned to either neutral (not connected). Because 120V GFCI's detect possible ground faults by sensing current differences between line and neutral (the assumption is that any difference is a ground fault), GFCI circuits immediately pop/fault, and you get nothing. In modern construction, all outside, garage, bathroom, and kitchen outlets are on GFCI's, so it's really hard to find a pair of outlets on different phases that will give you current. When I got it to work, it meant hauling extension cords into front hallways, etc.

There was an experiment performed at a hotel using 2 J1772 chargers on the forum somewhere. They were each 208v so naturally they were 120 deg out of phase. The experiment was an attempt to charge at 60A from two 30A stations. It would have worked if the building had been wired for split phase 240v. I've successfully done this at a campground using 2 NEMA 14-50 outlets - I did 70A. I did it once to see if it would work, but have never done it on a road trip because all the cables and large combiner box with two breakers is just too bulky to be worth it.

The problem here is to find the correct 208's to combine. Because there are three, if you pick one outlet, then there is, on average, only a one in three chance that another outlet will have the same phase and you can combine for higher current. You have to keep searching until you hit that one in three jackpot outlet. In a 240V split phase system, there is only one phase with a neutral, so you have a one in one chance of getting the correct phase from another outlet. You still have to deal with the chance that the line wires may have been reversed in the outlet install and have a provision to swap lines on one connection.

As you said, this is a lot of big gear with big extension cords...

 

[hcsharp]

I have used the Quick 220 Systems: Voltage Converters and they just throw away the neutral and use two line/hot sides and ground for the output. Quick 220 Systems: 20 Ampere Straight Blade Outlet is the one I have and it has a 6-20 output, which seems very reasonable. The big problem with these boxes is caused by how they work. All of the current passes through the two line/hot wires, and nothing is returned to either neutral (not connected). Because 120V GFCI's detect possible ground faults by sensing current differences between line and neutral (the assumption is that any difference is a ground fault), GFCI circuits immediately pop/fault, and you get nothing. In modern construction, all outside, garage, bathroom, and kitchen outlets are on GFCI's, so it's really hard to find a pair of outlets on different phases that will give you current. When I got it to work, it meant hauling extension cords into front hallways, etc.

There's another problem with these - a safety issue. Once you plug in the first plug, the other one is hot on one blade and it's easy to get shocked. Presumably Quick220 has a system to prevent this. On my homemade version I put a switch in it along with a digital voltage readout so I know when I have 240v. I just have to remember to turn the switch off when one leg is unplugged.

 

[FlasherZ]

There's another problem with these - a safety issue. Once you plug in the first plug, the other one is hot on one blade and it's easy to get shocked. Presumably Quick220 has a system to prevent this. On my homemade version I put a switch in it along with a digital voltage readout so I know when I have 240v. I just have to remember to turn the switch off when one leg is unplugged.

The "quick 220" will protect against this because it uses contactors to engage only when voltage is present from both supply circuits.

That said, I'll just say it again - just because it works doesn't mean it's safe. There is a failure scenario with the "quick 220" that can make parts that are thought to be grounded live at 120V. I describe the scenario here in more detail.

There is a reason that NEC requires all conductors (grounding, grounded/neutral, and ungrounded) of a branch circuit to run together - your safety.

There are manufacturers that will hide the risks of using such a device - some, for example, will claim that their device is UL-listed and is completely safe; what they don't tell you is that they certified it as a "safety power device" - a safety relay. They will also tell you that NEC doesn't apply because they are simply acting as an appliance, and that UL does all the safety you'll need -- what they don't tell you is that it was never tested as it will be used and the certification doesn't apply in that case. That said, it works, and plenty of people will rig up something to work in a pinch. I'd never deny someone the ability to handle an emergency, but I do want them to know the risks. It may carry liability or insurance risks that you must be aware of.

 

[ModelX]

Not sure if this is the best thread for posting. I was at a wonderful knitting retreat in Sister's Oregon at the Five Pines resort. They had two HPWC's and lovely service!

 

[Mark Vallaster]

This weekend I'm traveling to Asheville, NC from DC. We're staying at a new hotel downtown called the AC Hotel by Marriott. The web site says that it has two complementary changing stations in the garage. I called to see what the connection type was and the person I talked to was a bit clueless. Has anyone been to this hotel or has local knowledge to let me know what the connection is?

The last time I drove there I parked in a city garage that had 4 charging slots with J1772 connectors. Worked fine although they were a little out of the way from downtown.

Thanks in advance.