# An easier way to charge vehicles at home

#### tcp71

A reasonable question, but 480 volts is going to be three phase and your home is supplied with single phase electricity. Three phase is used for things like industrial motors and other commercial applications because it is more efficient. The wiring coming into your home is 240 volt, single phase, two pole. Three phase would NOT be the same as three pole.

Keep in mind, I am neither an electrical engineer nor and electrician, so we have now exceeded my knowledge of electric power.
Not quite. It's actually two legs of 120V 180degrees out of phase that gives most homes 220 (240) volts. So you actually DO have two phases into your home going to 2 rails in your electrical box. you then split off all the 110V outlets equally between the two rails and wire 220V using both rails.

#### tcp71

Why is everybody getting hung up on AC VOLTS ? It's all about DC CURRENT . The output ( amps ) of your charger is going to be limited by the input AC CURRENT available . Your average home is wired for 120/240 AC volts and usually no more than 200 amps .
because total power coming into your home is based on 220V and whatever current is being supplied into your home by the utility. Transformers and PWM power supplies can make the total power into whatever Volts or amps you want, but you can't exceed the total being supplied. Utilities don't supply DC current anywhere.

#### kschachn

Why is everybody getting hung up on AC VOLTS ? It's all about DC CURRENT . The output ( amps ) of your charger is going to be limited by the input AC CURRENT available . Your average home is wired for 120/240 AC volts and usually no more than 200 amps .
Right but it’s easier to get the needed watts with higher voltages. Less current and smaller wires, etc.

#### nomas

because total power coming into your home is based on 220V and whatever current is being supplied into your home by the utility.
And that is exactly what I said .

#### nomas

Right but it’s easier to get the needed watts with higher voltages. Less current and smaller wires, etc.
And like I said , you are usually limited to 120/240 volts input . And I'm not sure what watts and small wires have to do with charging a battery .

#### kschachn

And like I said , you are usually limited to 120/240 volts input . And I'm not sure what watts and small wires have to do with charging a battery .
Power is what is stored in a battery and watts are power. Your changing rate is watts (or kilowatts) per hour. And the smaller wires makes it less expensive to perform the installation both for the vehicle charger and the service drop.

#### nomas

Power is what is stored in a battery and watts are power. Your changing rate is watts (or kilowatts) per hour. And the smaller wires makes it less expensive to perform the installation both for the vehicle charger and the service drop.
And it's still at 240 VOLTS and a max of around 40 amps AC input . Right ? See why I'm asking ? Amps X Volts = Watts and both of them are limited by the size of your electrical service . The ORIGINAL post was about a new type of charging connection . Still limited to Level 2 .

#### Andrew1972

My wife’s aunts ski home was a converted industrial woodshop with a peaked roof /2nd floor added.

The first panel is 480V and I believe 3 phase power. It has a monster pull down switch. Next industrial panel is a massive pull down switch I think 240V then it has a normal run of mill 100AMP home panel for lights.

They run 3 wires to house off a separate pole from balance of street.

I think a super charger could be installed however who cares about 20 min - 60 min charging at home.

#### ecotourist

I have to believe that for the vast majority of home charging, a 240V 60A circuit is perfect.
Plus, charging with too much power is hard on batteries, right?
My charging station (a glamorous name for a basic 240 Volt outlet) is set up for 240 Volts and 40 Amps. My Tesla Model 3 Standard Range Plus charges at 32 Amps maximum and 80% of 40 Amps gives me those 32 Amps.

Installation of the outlet by a journeyman electrician including the wire cost me almost exactly \$500.

My routine charge is to 80%. For daily driving I almost never even look at the remaining charge. I just drive wherever I want and plug in when I get home.

#### George Bynum

No, it takes twice as long. Overnight is quite reasonable to be able to use an existing outlet. And how often is the meter anywhere near where the car is parked?
You're missing a point; MOST 120V connections are designed around 15A outlets and for "continuous" current are limited to 80% or 12A, thus 1440W.

MOST 240V charger connections are to 40A or 50A circuits; assume 40A, same 80% allows 32A or 7680W, about 5x faster.

#### CKN

I just don't know if this "electric vehicle thing" will ever take off.........🤣

#### denwood

There's also a question of efficiency at 120V. Most EVs will take 300 watts (and more if BMS calls for cooling the pack) or so to power the car's electronics while charging...so that's overhead regardless of 120V or 220V. If you charge for fewer hours, then you also incur less of that overhead. This is why 220V charging is "more efficient" then 120V. Less time charging, means less overhead.

I use 12 [email protected] at camp, as that's the only option, but at home, 16 [email protected] is perfect and is well within the 30 amp garage service capacity.

For many with 200 amp service, you likely would have no need for this device.

#### Jethro_Bob

Where I live, if a house was built with 100 amp service, The wire from the transformer to the meter was sized accordingly. So a panel upgrade here would also require an upgrade to the transformer. Might work in other areas, but older homes around here, not so much.

#### PandaBear

It's not 2x. It's closer to 4x to 8x.
Why? 110 is half of 220 so all things being equal, shouldn't it take just twice as long?
Typical 120V outlet is 10A. A pretty simple Watts Law calculation says this circuit can deliver 1200 watts.

Options vary when wiring up a 240V outlet, but 30A and 40A are pretty common. A 240V/30A circuit can deliver 7200 watts. Six times more power than a typical 120V household outlet.
Depends on how many amps you wire for. If you are not directly wiring it from the meter you are limited to any particular section along the way, and the AC guy wiring my AC from the meter directly use a much thicker wire than what was there from the meter to my panel.

A dedicated wire can do anything you wire it for, you can do 110V 40A if you want, but if you are doing dedicated wiring you obviously want to use 220V and 30-40A. 110A limits to 15A because they assume you are using a regular home circuit instead of a dedicated circuit. If you run 2 110V from different part of the house together to form your own 220V you will still be limited to 15A and therefore only 2x faster than 110V, not the dedicated 4x from 30A 220V.

I wonder how many amps you can wire for if you are running directly from the meter, bypassing the panel.

#### PandaBear

Power is Volts squared divided by Resistance. All being equal, twice the Voltage means 4 times the power so 220 Volts means charging 4 times as fast.
Only if your wiring can handle it without melting at 2x the current.

#### PandaBear

They are DC, the power is converted from HV AC, which is probably like 20,000V AC or something at minimum.
What are the typical voltage in commercial area before entering a commercial building? Are they really 20k VAC? or something lower like 1500VAC?

#### PandaBear

There are various schemes and ideas for providing higher voltage residential service but I don't know if any are implemented yet. One of the problems is that you still need nominal 120v/240v for most of the uses in the home which would mean either a transformer or a second service in addition to the higher voltage. 208v wye doesn't get you anything and a service with 480v would have a 277v leg. Good luck finding 277v refrigerators and lamps. As JeffKeryk notes it is just better to make sure the standard service drop has enough capacity. I do know they are installing 400A mains in some new homes just for this reason although sometimes the way that is implemented is through two 200A panels.
Depends on whether it is a new community with new wiring scheme or whether it is a retrofit of an old neighborhood.

For new neighborhood they can run high voltage 3 phase AC to each house and then step down at the house, but for old neighborhood it might be cheaper to run 220+220 to each house, step down 220 to 110 on each socket except the previous 220V range / dryer / AC to use 1 phase 220V directly (move 1 wire to ground), and charge your EV with 440V at the same current. This will be only socket changes and should be the cheapest in labor.

#### OVERKILL

##### \$100 Site Donor 2021
What are the typical voltage in commercial area before entering a commercial building? Are they really 20k VAC? or something lower like 1500VAC?
Somewhere below 44kV according to Hydro ONE here in Ontario:

From what I've read, distribution voltage is typically 3.3kV-25kV in the US. This is what hits the "point of use" where the step down transformer on the pole drops it down to the voltage the customer needs.

#### brianl703

From what I've read, distribution voltage is typically 3.3kV-25kV in the US. This is what hits the "point of use" where the step down transformer on the pole drops it down to the voltage the customer needs.

Most common in the USA (at least in terms of square miles served) is 12.47/7.2kV wye, and transformers are usually connected phase-to-neutral (7.2kV) This is the Rural Electrification Administration standard which I believe was set in the 1930s.

In big cities (Chicago, New York) you often find distribution voltages lower than 7.2kV, from what I've heard, and they also may use delta where there is no neutral (on the primary side) and the transformer is connected phase to phase.

Suburbs and rural areas are more likely to be 7.2kV. EDIT: And they often don't have all 3 phases run down the street, instead getting only a single phase. Which means 3 phase service is not an option.

And there are places that use a distribution voltage higher than 7.2kV, but this isn't as common.

A bit of trivia: A transformer designed to be connected phase-to-neutral is cheaper than one designed to be connected phase-to-phase, because in addition to not needing an additional bushing (the insulator sticking out the top where the primary is connected), they don't need to be fully voltage-rated since one end of the primary coil is at 0V potential.

#### brianl703

Not quite. It's actually two legs of 120V 180degrees out of phase that gives most homes 220 (240) volts. So you actually DO have two phases into your home going to 2 rails in your electrical box. you then split off all the 110V outlets equally between the two rails and wire 220V using both rails.

Most houses are fed by a single-phase transformer, with a center tap on the secondary which is connected to neutral. It is not technically correct to call the output of this transformer "two phases". Split-phase is the more correct term, and the output of the transformer is often referred to as L1 and L2 plus N. And between L1 and L2 you get 240V and between L1 and N you get 120V and L2 and N also 120V.

Some apartment and most commercial buildings are fed with a bank of 3 single-phase transformers, the primary of each connected to one of the 3 phases.

And if there are no 3-phase loads, like an in apartment, then they can use a less expensive load center like that normally used with split-phase service. In this case, 2 phases plus a neutral are fed to this type of load center giving you 208V phase-to-phase and 120V phase-to-neutral. (This kind of stinks for EV charging, because most EVs charge slower on 208V than they do on 240V. They could install a boost transformer to increase the 208V to 240V but nobody seems to do that...)