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240v charging from two 120v receptacles
- Thread starter factorytuned2012
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Might be a solution if you’re visiting someone and need to charge your car.
Here’s my question though.
I was under the impression for best charging you want 240v 50 amp outlet
I assume if you plug it into a 240V 30 amp outlet that the car charger will adjust to the lower amperage?
I won’t get into the high current draw of a 50 foot extension cord that is not properly sized.
Here’s my question though.
I was under the impression for best charging you want 240v 50 amp outlet
I assume if you plug it into a 240V 30 amp outlet that the car charger will adjust to the lower amperage?
I won’t get into the high current draw of a 50 foot extension cord that is not properly sized.
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yes like you mention on vacation or visiting is fine but I would not rely on that as my dedicated charging method for an ev
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depends on the transformer feeding your home/building.. It's similar to a shared neutral multi-wire branch circuit. each leg of my panel is 120 therefore I would get 240v.. that's why you can't use a GFCI protected circuit
You’d have to have some way for the vehicle to know or turn it down manually before you start charging via the vehicle screen. Most of the EVSEs can recognize the attached adapter and limit it. For example this setup should be limited to 24a.
You’re correct that a 50a would be ideal.
If the branches are 180 degrees apart that is true. However, it is unlikely they are 180 degrees apart. Easily confirmed with a RMS responding voltmeter.
Typical residential is 180 degrees and yields 120/240 volts. Typical commercial is 208/120 three phase and is 120 degrees apart. I’ve never seen a residential 208/120 service.
You will get 208V if connected to two phases on a 3 phase feed, most houses have one/two phases, you can get 240V if connected to two opposite phases but not on 3 phase feed.
That's what it is at work when I plug in. Shows me 208v 48a. I wasn't sure why there's a difference as my electrical is in low voltage vehicle applications.
Nope it should be limited to 12 amps. It'd be twice as fast as using a single 120 outlet though. If you look at 59 seconds into that video, they're drawing 16 amps from a 15 amp outlet, a no-no.
Yep, you're right, it's not a standard 240v output. I forgot amperage doesn't double, only the voltage does.
My condo has 208/120v service.
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Well this is where the manufacturer of the charger is at fault. For starters they should be warning that the charger should be used only on 20A circuits(for safety purposes). the face of a standard duplex receptacle could be on a 15 or 20A circuit. the vehicle is showing 16A overall my thinking is the charger is designed to pull power from both sides of the electrical panel theoretically its probably 8A from cord A and cord B together equaling 16A. if this is the case then it would be ok for a 15A circuit especially if there is equal current on both cords if not the neutral would be carrying the unbalanced load which could overheat the neutral during prolonged charging. its not ideal and shouldn't be used for a dedicated means of charging. just my 2 cents.
I really don't like this crazy workaround. If I needed to charge and I didn't have 240V where I was I'd just use the 120V adapter. I keep the Tesla one in my car with the standard 120V adapter, 14-30, and 14-50 while I'm on trips. Doing this would require me to carry this box, two heavy duty long extension cords which if you did this would cost close to $200 alone. I have a heavy duty extension cord ran from my garage to my green house and that one was $85 on sale. This isn't a place to cheap out with high current draw.
When people ask me about buying an EV, the 1st thing I say is, "How ya gonna charge?"
I'm pretty sure that Level 2 charging systems just pass on AC power to the car and the car can regulate it like most switching power supplies do. Most would be expecting whatever is specified by the plug type and I believe limiting the amperage. Some people have been testing different improvised setups and found a voltage drop that was reported by the onboard charging system of the car. Or where a power utility's system was going batty and put out a nonstandard (possibly changing) voltage. Apparently a Tesla can handle anything between about 90V to 260V although I'm not sure how it would regulate current. I thought that with a Mobile Connector the plug type gives a signal that sets a current limit.
Yeah probably. My old apartment was too. It gives them three legs of 120v plus three-phase if there are any motors such as for an elevator.
The problem is relying on the end consumer to know what to do with the given information. That's at the enthusiast level typically and that concerns me for the basic user trying to do this.
The car needs to know the available power supply to limit it. That's why the plug design matters instead of using an aftermarket adaptor extension to make the EVSE match the outlet. When I use the 14-30 Tesla adaptor I can't turn it up past 24a. The 14-50 Tesla adaptor limits to 32a(or 48a depending on EVSE brand). It does have the ability to request more than the power supply can safely deliver with the wrong input information.
I'm thinking that someone must have tried using a Tesla Mobile Connector overseas with a 5-15 plug and an adapter to a 220-240V outlet. I wouldn't recommend it, but there must have been someone who did that, whether by not knowing it wasn't recommended or intentionally to see what happens.