110 vs 220

[Stan Moraski]

I would imagine this has been addressed, but forgive me; new to the forum. I have time occasionally to charge my 2013 P85 in my regular plug in the garage (4 mph), or the 220 I had installed (23 mph). Wondering the amount of energy $$ difference there is in the two scenarios.

Thank You in advance!

 

[whitecotton]

Same amount of energy is being consumed. I guess the higher amperage has a higher loss due to heat, but if you are getting that specific you would have to take in account the extra runtime of the computers and pumps while charging 110v due to the increase in time charging.

 

[Cosmacelf]

Charging at 120V is less efficient since the car uses a certain amount of energy while charging. This is energy overhead that isn't going into the battery. How much is this overhead is anyone's guess, but seems that about 600W is about right. Charging at 120V draws 1,440 watts. So almost half the energy drawn from the wall is wasted when charging at 120V. Compare that to a 240V/50A circuit when you are drawing 240V/40A, or 9,600 watts. Here only 600/9600 = 6% of the energy taken from the wall is lost to overhead.

This is why charging using the Tesla 5-20 adapter from a 120V receptacle is so much better than using the supplied NEMA 5-15 adapter. You draw 16A instead of 12A (33% more power drawn from the wall), but your actual charge rate increases by about 42%. This only applies if your receptacle has a 20A breaker, which most newer houses do have.

 

[TexasEV]

Hearing 110 and 220 is like nails on a chalkboard. It’s 120 and 240V. And as above, charging at 240V is more efficient than 120V. The latter is only if you have no other option.

 

[Don85D]

It's my understanding that power consumed from both sides of the line (240 VAC) is more efficient than taken from one side only (120 VAC) unless you have other loads on the opposite line to balance L1 and L2 again.

I agree that charging at 120 VAC is painfully slow and only for times when faster charging is not possible.

 

[Saghost]

Energy cost to you depends very much on how your electric bill is set up - things like demand charges and time of use billing can swing that in either direction.

In terms of pure efficiency, I remember reading a thread here on TMC that concluded that 240V/24A appeared to be the most efficient rate, but my GoogleFu is apparently weak today - unless you're charging in the cold, the overall differences will be small (in the cold, the car has to heat the pack as well, which can eat more power than a 120V 5-15 outlet can safely deliver.)

 

[Cosmacelf]

Hearing 110 and 220 is like nails on a chalkboard. It’s 120 and 240V. And as above, charging at 240V is more efficient than 120V. The latter is only if you have no other option.

I would say 95% of people use 110 and 220 rather than the correct 120 and 240. Heck even the company that makes a product that combines 120v legs into 240v calls their product Quick220. The North American power grid standardized on 240v nominal going into the house over 70 years ago. The last time 110v was really a thing was Edison’s 110v DC power plants around 1900.

The reason 110v never dies is that no one is educated about it. You can get a friggin PHD in any field and never, ever, learn about the basics of household electricity that any 1st year technical school student learns. It reminds me of how no one ever gets taught basic economics leaving them dangerously open to believing all sorts of destructive nonsense. When you think about, it is rather alarming how little people are taught about the basics of how things work in our society. And then we wonder why people are so ignorant, yet believe they know so much since they went to so many years of school.

 

[deonb]

I would say 95% of people use 110 and 220 rather than the correct 120 and 240.

Actually I think 110 and 220 is more like 75%. A further 20% use 110 and 240. This includes most electricians I've talked to.

 

[gavine]

I have had countless people ask me if I put a 220 in my garage and when I tell them it’s a 240, they look at me like I have two heads.

 

[azdryheat]

220, 221, whatever it takes.

 

[K-MTG]

Why not just get a quick 220 if you can't install a 240V outlet?

 

[whitex]

Why not just get a quick 220 if you can't install a 240V outlet?

It will be better than charging from a single 120, but you can still only safely draw 12A max.

 

[Cosmacelf]

I have had countless people ask me if I put a 220 in my garage and when I tell them it’s a 240, they look at me like I have two heads.

But that’s because you do

 

[Chaserr]

I have one of those Quick 220 boxes for a summer house with no 240v feed. At that old house with bad/not modern wiring, the car charges 120v 12A at a rate of 3mph, and 10mph through the Quick220 (also at 12A) at the same location. This does confirm what people have said about the car using half of a standard 120v plug just to keep the car's systems running, as it seems to add double or more with the second 120V added on.

I wouldn't recommend one of these boxes unless rewiring is such a monumental effort it isn't worth it (in the case of the summer home the local electricians all said they'd need to rewire the house completely before they could upgrade or run a new line which I felt was overkill on a place we spend a month or two at per year) but for the niche cases that it makes sense, these boxes do work.

 

[Cosmacelf]

Why not just get a quick 220 if you can't install a 240V outlet?

Combining 120V outlets is trickier than it sounds. First, neither outlet can be GFCI protected, which eliminates most garage outlets in newer houses. Then, both outlets must be wired on different legs of the electrical panel. I have successfully charged using my own 120V combiner in a rented condo, but I had extension cords literally dangling from the second floor down to the garage to find opposite leg outlets. Not for the faint of heart. It was only marginally easier than the other time I had a rented condo and took off the electrical panel cover to put in my own 50A breaker to charge. That’s a fun one too. Luckily, on neither trip was my wife with me or I’d never hear the end of it

 

[whitex]

Combining 120V outlets is trickier than it sounds. First, neither outlet can be GFCI protected, which eliminates most garage outlets in newer houses. Then, both outlets must be wired on different legs of the electrical panel. I have successfully charged using my own 120V combiner in a rented condo, but I had extension cords literally dangling from the second floor down to the garage to find opposite leg outlets. Not for the faint of heart. It was only marginally easier than the other time I had a rented condo and took off the electrical panel cover to put in my own 50A breaker to charge. That’s a fun one too. Luckily, on neither trip was my wife with me or I’d never hear the end of it

For the future, if it's a place you go to repeatedly , there is a 3rd option between running long extensions and installing a NEMA 14-50. Just find 2 closest sockets on different fuses, and if they are on the same phase/leg, move the circuits (or entire breakers) in the main panel to put then on different phases/legs.

 

[Chaserr]

For the future, if it's a place you go to repeatedly , there is a 3rd option between running long extensions and installing a NEMA 14-50. Just find 2 closest sockets on different fuses, and if they are on the same phase/leg, move the circuits (or entire breakers) in the main panel to put then on different phases/legs.

This is what I did at the summer house. I purchased a few heavy duty extensions anticipating a run from the other side of the house for one leg, but lucked out and found that 2 outlets 3 feet apart in the garage were suitable for the Quick220 box to function.

 

[dhanson865]

I would imagine this has been addressed, but forgive me; new to the forum. I have time occasionally to charge my 2013 P85 in my regular plug in the garage (4 mph), or the 220 I had installed (23 mph). Wondering the amount of energy $$ difference there is in the two scenarios.

Thank You in advance!

Welcome to the United States, I hope your immigration from your home country has gone well.

The US has used 120v and 240v for more than 75 years, as far as I can tell the switch to 120v predates WWII.

In 1942, the Edison Electric Institute published the document Utilization Voltage Standardization Recommendations, EEI Pub. No. J-8. Based on that early document, a joint report was issued in 1949 by the Edison Electric Institute (EEI Pub. No. R6) and the National Electrical Manufacturers Association (NEMA Pub. No. 117). This 1949 publication was subsequently approved as American National Standard EEI-NEMA Preferred Voltage Ratings for AC Systems and Equipment, ANSI C84.1-1954.

I can't say what year your state or local utility switched to 120v. But it likely was prior to 1942. That's just as far back as I've traced it.

 

[NeverFollow]

I would add also that in some locations you might have higher rates during the day and lower rates at night.

If so, you would have advantage to charge as much as you can during the night than charging the whole day.

For example, in California PG&E provides lower rates from 11 pm until 7 am.

I am not sure of the rates (just an estimate) so for example:

Off-peak: 11 pm - 7 am = 8 H @ $.20

Partial-peak: 7 am - 1 pm + 8 pm - 11 pm = 9 H @ $.25

Peak: 1 pm - 8 pm = 7 H @ $0.30


240 V - 20 A - 08 H ~ 38.400 KW --> Total cost: $7.68

120 V - 12 A - 24 H ~ 34, 560 KW --> Total cost: ($2.30 + $3.24 + $3.02) = $8.56


In this example, using 240 V you get 4 KW more than using 120 V and you paid $1 less.

This calculation was very simplistic, I did not included any lost and so on, just to have an idea.

(I hope I don't fool myself...)

 

[Don85D]

There is also 208VAC which is one leg of a 3 phase connection. In Europe I think that 220VAC is still the standard so everyone is right at some time or place. It really doesn't matter unless you are measuring voltages looking for losses.