Electric charging stations

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sparks27

Member
Location
Portland, Oregon
Do all electric vehicles have 220v capability for charging? or is their special equipment to install, so it can be charged with a 220v dedicated circuit? I perform inspections in a retirement community, and some folks are wanting charging in their carport space, for their electric vehicles. We are looking at creating a policy of what the community will allow and not allow as far as outlets for charging. we have a limited number of circuits available, and need to maximize the circuits and load that's available from our panel. The 220v circuits will keep our total Amps lower if 220v is available for all of the vehicle chargers.

I hope this is posted in the correct forum....
Appreciate any replies Thanks Sparks :)
 

Ponchik

Senior Member
Location
CA
Occupation
Electronologist
Most vehicle chargers (at least the ones that I have installed for individual owners) are 240V rated at 7.2KW that require a wall mounted chargers.

I am sure the manufacturers do make chargers for multi unit complexes or commercial chargers for multiple vehicles that may be a better solution for you.
 

goldstar

Senior Member
Location
New Jersey
Occupation
Electrical Contractor
A lot depends on the type of vehicle and what it comes equipped with. Some vehicles can be charged with a 120 volt charger. It can take up to 10-12 hours to charge the vehicle. If you want a more rapid charge I believe the next size up is a 30 amp/240 volt charger that will charge in half the time. Then there are 3-phase commercial chargers (like for electric buses, etc.) that will charge a vehicle in an hour or two. I would check the vehicle specs first and then make a decision to install one (or more) that would be the most common. I believe the cords that come with the vehicles are different as well. From the CEU's that I have taken in the past I believe you'll probably find that the 30 amp charger is the most common. However, I'm not up on the latest technology and manufacturers may have changed their designs. From what I've been told there will be multi-user charge stations (like for parking garages) the will accept credit cards for the time it uses to charge the vehicle.
 

Aleman

Senior Member
Location
Southern Ca, USA
We have a dual station EV charger at work. All it does it plug the car into 220V. It has some fancy current monitoring
built into it but essentially a 220V 40A supply and a contactor. Seems to be universal for EV cars.
 

sparks27

Member
Location
Portland, Oregon
A lot depends on the type of vehicle and what it comes equipped with. Some vehicles can be charged with a 120 volt charger. It can take up to 10-12 hours to charge the vehicle. If you want a more rapid charge I believe the next size up is a 30 amp/240 volt charger that will charge in half the time. Then there are 3-phase commercial chargers (like for electric buses, etc.) that will charge a vehicle in an hour or two. I would check the vehicle specs first and then make a decision to install one (or more) that would be the most common. I believe the cords that come with the vehicles are different as well. From the CEU's that I have taken in the past I believe you'll probably find that the 30 amp charger is the most common. However, I'm not up on the latest technology and manufacturers may have changed their designs. From what I've been told there will be multi-user charge stations (like for parking garages) the will accept credit cards for the time it uses to charge the vehicle.

I perform bldg. inspections for a Retirement community we will be required to allow, some form of charging for the people with electric vehicles. it looks like the individual carport spaces will need some type of charger installed (Their charge)
But what type to allow, and the most efficient for the Management co. we pay the utilities then collect from them a flat charge per month for electricity. I would think the 30A 220v chargers would charge for less time, and less current draw
than the 120v 20a chargers. we will probly set one up to charge and get some readings on current use and figure a amount to charge these folks. The electric service is another issue to be figured out as well. Thanks, sparks
 

GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
Just like gasoline, the electric energy used will depend on the miles driven, so you will have to guess an average weekly mileage to convert your single charge cycle measurement to a monthly fee.
 

sefs

Member
Location
Gibsonia, PA
Do all electric vehicles have 220v capability for charging? or is their special equipment to install, so it can be charged with a 220v dedicated circuit? I perform inspections in a retirement community, and some folks are wanting charging in their carport space, for their electric vehicles. We are looking at creating a policy of what the community will allow and not allow as far as outlets for charging. we have a limited number of circuits available, and need to maximize the circuits and load that's available from our panel. The 220v circuits will keep our total Amps lower if 220v is available for all of the vehicle chargers.

I hope this is posted in the correct forum....
Appreciate any replies Thanks Sparks :)

All electric vehicles complying to the SAE J1772 standard are able to charge from 120V/208V/240V 60Hz single phase supplies. Almost all mass market vehicles (excluding DIY EV's) will be compatible with the J1772 standard. With that in mind, a quick background to the standard will be helpful to this discussion. J1772 is simply a means of connecting onboard chargers within the vehicle to a supply while minimizing the risk of electric shock and circuit overload without the need of the user to intervene. J1772 mitigates electric shock through a "make before break" pins connection strategy, a proximity switch which is depressed when the user wants to release the plug from the vehicle's receptacle, and through use of a ground fault interruption protection scheme set a bit higher than a Class A protection device. The J1772 EVSE has a contactor inside which does not close until it hears from the vehicle stating it is okay to start. The overload protection is accomplished through a square wave with variable duty cycle, which "advertises" the maximum allowable current to be drawn. This is always 80% of the OCPD feeding the EVSE. The vehicle then reads this value, and per the standard, does not exceed this value. This value can be higher than what the vehicle is capable of drawing. Think of the J1772 EVSE (what some refer to as a charging station) as a smart extension cord.

The standard allows up to 16A to be drawn at the 120V, or Level I, voltage level. Almost all vehicles will only be able to draw 12A from a Level I source. All vehicles sold recently come with a Level I EVSE that is plug connected to a NEMA 5-15P. This allows for charging away from dedicated a EVSE. This will draw a constant 12A from a 5-15R. If using an existing outlet, the user must be wary of overloading the circuit if it is not a dedicated circuit. As a side note, EVSE's do not exceed any safe level of current draw on outlets, but if there is any deficiency in the wiring, a constant 12A load on a standard 15A or 20A circuit will make that clear pretty quickly. Old, loose receptacles and loose connections can quickly heat up and become an issue. Be sure to use a new, quality receptacle when dedicating an outlet to EV charging.

Moving on to 240V, or Level II, charging. These can be plug connected or hard-wired. The ampacity scheme is the same. The EVSE advertises the maximum allowable current, and the vehicle complies. The key difference here is the maximum the vehicle will be able to draw. For example, a common EVSE setup is a Level II EVSE on a 40A double pole breaker. The EVSE will advertise 32A to the vehicle. If a vehicle with a capable onboard charger plugs in, it will draw the full 32A. However, if a vehicle with a lower capacity onboard charger plugs in, for example the Chevy Volt, it's maximum charger current is 15A at 240V. So, even though it is being told it can draw 32A, it will only draw what it can. Level II charging can range anywhere from 6A (which is pretty uncommon) to 80A. The sweet spot for the majority of plug in vehicles would be the 32A level. However, if capacity is an issue, a 12A Level II EVSE will still supply twice the power as a 12A Level I EVSE, cutting charging time in half.

The home is where the majority of users will be charging, and from a design standpoint you want to get them as much power as you can without overloading your service. However, with what you stated, you probably do not have that much capacity left in your system. A bare bones basic approach would be to provide a 15A, dedicated 5-15R GFCI outlet for charging. This will get the job done, but if residents drive more than a dozen or so miles a day, they will be left without a full charge. A 20A outlet will only be useful to residents with a Tesla Model S or Roadster. All other vehicles can only charge at 12A at the 120V level, so think twice before using up more of your load calculation to give 20A circuits and 5-20R's. Now, moving to 240V will not reduce the demand by your users. The minimum you'll be able to install will be a 12A Level II EVSE. If you can do 12A Level II, I would try to accommodate it, simply for the reason that charging 12A at 120V can take upwards of 15 hours for a full charge. Another design consideration is wire gauge. These devices will be drawing the 80% capacity for upwards of 3 hours, possibly to over 24 hours. Voltage drop can be an issue if the circuits are long. I would suggest at least going to the next gauge up to combat this issue. Lower voltage simply means less power for the vehicle's charger, which will not exceed the advertised current level; so more time charging.

So, in summary, you have the option to install whatever combination you like in terms of voltage level and ampacity. You have to figure how many spaces you want to serve and what that will mean for your service capacity and load calculations.
 

rlundsrud

Senior Member
Location
chicago, il, USA
Sefs's post pretty much said it all, but I would like to expand on the voltage drop point. I would be careful to actually do a VD calc as some charging stations can be a significant distance from the distribution system. An excessive drop can affect the sensing electronics of some manufacturers stations which could have undesirable results. Also be sure to check the manufacturers specs as I believe there was at least one that required the VD to be <2%.
 

sparks27

Member
Location
Portland, Oregon
All electric vehicles complying to the SAE J1772 standard are able to charge from 120V/208V/240V 60Hz single phase supplies. Almost all mass market vehicles (excluding DIY EV's) will be compatible with the J1772 standard. With that in mind, a quick background to the standard will be helpful to this discussion. J1772 is simply a means of connecting onboard chargers within the vehicle to a supply while minimizing the risk of electric shock and circuit overload without the need of the user to intervene. J1772 mitigates electric shock through a "make before break" pins connection strategy, a proximity switch which is depressed when the user wants to release the plug from the vehicle's receptacle, and through use of a ground fault interruption protection scheme set a bit higher than a Class A protection device. The J1772 EVSE has a contactor inside which does not close until it hears from the vehicle stating it is okay to start. The overload protection is accomplished through a square wave with variable duty cycle, which "advertises" the maximum allowable current to be drawn. This is always 80% of the OCPD feeding the EVSE. The vehicle then reads this value, and per the standard, does not exceed this value. This value can be higher than what the vehicle is capable of drawing. Think of the J1772 EVSE (what some refer to as a charging station) as a smart extension cord.

The standard allows up to 16A to be drawn at the 120V, or Level I, voltage level. Almost all vehicles will only be able to draw 12A from a Level I source. All vehicles sold recently come with a Level I EVSE that is plug connected to a NEMA 5-15P. This allows for charging away from dedicated a EVSE. This will draw a constant 12A from a 5-15R. If using an existing outlet, the user must be wary of overloading the circuit if it is not a dedicated circuit. As a side note, EVSE's do not exceed any safe level of current draw on outlets, but if there is any deficiency in the wiring, a constant 12A load on a standard 15A or 20A circuit will make that clear pretty quickly. Old, loose receptacles and loose connections can quickly heat up and become an issue. Be sure to use a new, quality receptacle when dedicating an outlet to EV charging.

Moving on to 240V, or Level II, charging. These can be plug connected or hard-wired. The ampacity scheme is the same. The EVSE advertises the maximum allowable current, and the vehicle complies. The key difference here is the maximum the vehicle will be able to draw. For example, a common EVSE setup is a Level II EVSE on a 40A double pole breaker. The EVSE will advertise 32A to the vehicle. If a vehicle with a capable onboard charger plugs in, it will draw the full 32A. However, if a vehicle with a lower capacity onboard charger plugs in, for example the Chevy Volt, it's maximum charger current is 15A at 240V. So, even though it is being told it can draw 32A, it will only draw what it can. Level II charging can range anywhere from 6A (which is pretty uncommon) to 80A. The sweet spot for the majority of plug in vehicles would be the 32A level. However, if capacity is an issue, a 12A Level II EVSE will still supply twice the power as a 12A Level I EVSE, cutting charging time in half.

The home is where the majority of users will be charging, and from a design standpoint you want to get them as much power as you can without overloading your service. However, with what you stated, you probably do not have that much capacity left in your system. A bare bones basic approach would be to provide a 15A, dedicated 5-15R GFCI outlet for charging. This will get the job done, but if residents drive more than a dozen or so miles a day, they will be left without a full charge. A 20A outlet will only be useful to residents with a Tesla Model S or Roadster. All other vehicles can only charge at 12A at the 120V level, so think twice before using up more of your load calculation to give 20A circuits and 5-20R's. Now, moving to 240V will not reduce the demand by your users. The minimum you'll be able to install will be a 12A Level II EVSE. If you can do 12A Level II, I would try to accommodate it, simply for the reason that charging 12A at 120V can take upwards of 15 hours for a full charge. Another design consideration is wire gauge. These devices will be drawing the 80% capacity for upwards of 3 hours, possibly to over 24 hours. Voltage drop can be an issue if the circuits are long. I would suggest at least going to the next gauge up to combat this issue. Lower voltage simply means less power for the vehicle's charger, which will not exceed the advertised current level; so more time charging.

So, in summary, you have the option to install whatever combination you like in terms of voltage level and ampacity. You have to figure how many spaces you want to serve and what that will mean for your service capacity and load calculations.

Wow, thanks for the information.
I am thinking we can offer the residents a 220v 20a level II circuit , for charging at their carport space. I don't think we can allow a 40 amp circuit because the capacity of our service will quickly max out.

The way we are looking at this, is we have a laundry room with a 200a service feeding about 6 washers and dryers
plus 2- 80 gal water heaters, all electric appliances. This retirement community has no gas at the apartments, (scary thought) :)
I wanted to run a sub panel of 125a 24 cir. at the carport and then supply individual outlets to the residents who wanted to charge the elect. vehicles. some of these conduit runs will be over 100ft. from the subpanel,
Possibly another 100ft. from the main service at the laundryroom. So I have some loads to figure here, and some wire upsizing for voltage drop as well. I am anticipating about 5 residents will want charging at their spaces, for now
This vehicle charging is becoming more popular here in in our community, it is expensive for most folks
but there are some that absolutely want this option. thanks, sparks
 
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