Charging setup for my condo garage parking space

[Eric33432]

FYI, looking something else up I found out that each building is 4000 amps at 480/277 volts (I guess this means 3 phase)
Depending on how that math works it is 1 or 2 MW. 50 L2 chargers (usually 6kw) would be 300kw, so a pretty big add to a parking garage that has just some lighting and elevator. (lighting: ~1500 stalls with about 25w or 50w of LEDs, with sensor per stall is only 75kw

Most buildings in the US (and probably Canada) that have large power demands for things like air conditioning, elevators, etc., are provided 480/277. Even a typical Home Depot or Lowes would normally be provided 480/277. The air conditioning runs on 480 3 phase, and the lighting on 277. Then there are step down transformers for all the 208/120 volt loads.

BTW, 4000 amps at 480 volts 3 phase is 3,321,600 watts (4000 x 480 x 1.73).

I suppose in your case, the Tesla Wall Connectors in your building are connected to 208 volt power provided by a step down transformer.

It is interesting that Tessies can be charged from 277 volt power, but Tesla has dropped official support for this. If 277 volts was supported, it would be less expensive for large scale EVSE installations (assuming other EVs also support 277 volt AC charging), because there would be no need to install the large and expensive step down transformers. Also, the size of the wiring for the electrical service would be less than half the size.

 

[davewill]

Most buildings in the US (and probably Canada) that have large power demands for things like air conditioning, elevators, etc., are provided 480/277. Even a typical Home Depot or Lowes would normally be provided 480/277. The air conditioning runs on 480 3 phase, and the lighting on 277. Then there are step down transformers for all the 208/120 volt loads.

BTW, 4000 amps at 480 volts 3 phase is 3,321,600 watts (4000 x 480 x 1.73).

I suppose in your case, the Tesla Wall Connectors in your building are connected to 208 volt power provided by a step down transformer.

It is interesting that Tessies can be charged from 277 volt power, but Tesla has dropped official support for this. If 277 volts was supported, it would be less expensive for large scale EVSE installations (assuming other EVs also support 277 volt AC charging), because there would be no need to install the large and expensive step down transformers. Also, the size of the wiring for the electrical service would be less than half the size.

My understanding is that 277v is making a comeback in the new J3400 (the SAE version of NACS). AFAIK, all Tesla cars (and certainly all current models) can handle 277v charging, and the Gen1/2 Wall Connectors support it. It was the Gen3 Wall Connector that removed 277v support, not the cars themselves. So a new wall connector, or possibly even a WC firmware update, could bring it back.

 

[SVMike]

I suppose in your case, the Tesla Wall Connectors in your building are connected to 208 volt power provided by a step down transformer.

Actually they are ChargePoint. And they are 208v

 

[Concerned]

Yes. I think so. You'd install them In banks of six that load balance within each bank. The banks could be on one or more circuits. For 100 EVSEs, You'd need enough power available to support about 17 circuits at whatever power level you wanted to provide to the vehicles. e.g., if you want to support 40A L2 charging, you'd need about 17*50A of available 220/240v power. If you want to support 32A L2 charging, you'd need 17*40A.

Other providers like SWTCH and Atom have excellent whole-circuit load balancing that should be considered for big installs. For example, SWTCH could load balance across all 100 EVSEs. So, if you put all 100 EVSEs on a single panel (probably not possible or desired, but go with me), SWTCH would throttle all the EVSEs to keep the total load below that panel's limits. With the right install, I believe SWTCH can even manage to the limits of the whole building's transformer, so you can even oversubscribe the whole building circuit.

Obviously, these types of installs get complicated and require serious thought and analysis to ensure you are managing your available power correctly. IOW, get expert help.

I’m actually installing this for a 100 EVSE’s and have the order placed with Tesla for the equipment. We intend to use groups of five UWC’s load sharing 21 kW, and providing 50 ampere circuits to each device. The total load is served by a 500 kW transformer and a 1600 ampere switchboard serving 225 ampere panel boards. In NJ with union labor, installed on a ground based lot, this is close to a $3.5MM investment for our employees. Our issues right now are all driven by using our guest network lan for the load management and comms to Tesla. The power side is easy. I’ve been a practicing power engineer for 35 years…. Perception of the management of the system and who can connect seem to be causing consternation. Heretofore, I’ve installed hundreds of J1772 with a closed 3rd party and / or charge point Trying the Tesla solution, Hopefully they’ve solved many issues, yet the human behaviors and basic charging etiquette remain. Having every spot in a lot powered is impractical to say the least. The UWC doesn’t support 277V which would make install easier yet I’ve been intentionally trying to remove 277v from our facility distribution systems to minimize ground fault risks and with the advancements of LED lighting, and daylight harvesting, they all can economically be 120v loads.. so aside from electric reheat, (uggh) or a basin heater in a cooling tower, beyond Gen 2 chargers there’s no longer a need for a neutral. Regardless, this is a costly exercise for a condo association.

 

[davewill]

I’m actually installing this for a 100 EVSE’s and have the order placed with Tesla for the equipment. We intend to use groups of five UWC’s load sharing 21 kW, and providing 50 ampere circuits to each device. The total load is served by a 500 kW transformer and a 1600 ampere switchboard serving 225 ampere panel boards. In NJ with union labor, installed on a ground based lot, this is close to a $3.5MM investment for our employees. Our issues right now are all driven by using our guest network lan for the load management and comms to Tesla. The power side is easy. I’ve been a practicing power engineer for 35 years…. Perception of the management of the system and who can connect seem to be causing consternation. Heretofore, I’ve installed hundreds of J1772 with a closed 3rd party and / or charge point Trying the Tesla solution, Hopefully they’ve solved many issues, yet the human behaviors and basic charging etiquette remain. Having every spot in a lot powered is impractical to say the least. The UWC doesn’t support 277V which would make install easier yet I’ve been intentionally trying to remove 277v from our facility distribution systems to minimize ground fault risks and with the advancements of LED lighting, and daylight harvesting, they all can economically be 120v loads.. so aside from electric reheat, (uggh) or a basin heater in a cooling tower, beyond Gen 2 chargers there’s no longer a need for a neutral. Regardless, this is a costly exercise for a condo association.

Fascinating install! Has Tesla been willing to supply technical support or maybe even design help? As a computing professional, one thought that immediately comes to mind is that you're trying to do this on your "guest" network. I would probably want to provision a separate network with it's own security rather than try to coexist with other users. It would help if the UWC supported hard-wired network connections, but I don't think it does.

While 277v might make your install easier, I think that too many of your employees' cars wouldn't support it, but you surely know that.

On a separate topic, I had occasion to use some destination charging at a hotel last week. I didn't find out until later the next day that I had been charged for the session. There was nothing posted and nothing in the car to tell me I was being charged or how much. In fact, the car never showed the billing charge at all, I only saw it in a message sent to the app.

I didn't mind paying, and the rate was reasonable enough, but I kind of like to know these things ahead of time. Obviously, the hotel should have signage, but without a display on the wall connector, the car should have told me, ideally before I even plugged in. Tesla has some kinks to work out.

 

[Eric33432]

I’m actually installing this for a 100 EVSE’s and have the order placed with Tesla for the equipment. We intend to use groups of five UWC’s load sharing 21 kW, and providing 50 ampere circuits to each device. The total load is served by a 500 kW transformer and a 1600 ampere switchboard serving 225 ampere panel boards. In NJ with union labor, installed on a ground based lot, this is close to a $3.5MM investment for our employees. Our issues right now are all driven by using our guest network lan for the load management and comms to Tesla. The power side is easy. I’ve been a practicing power engineer for 35 years…. Perception of the management of the system and who can connect seem to be causing consternation. Heretofore, I’ve installed hundreds of J1772 with a closed 3rd party and / or charge point Trying the Tesla solution, Hopefully they’ve solved many issues, yet the human behaviors and basic charging etiquette remain. Having every spot in a lot powered is impractical to say the least. The UWC doesn’t support 277V which would make install easier yet I’ve been intentionally trying to remove 277v from our facility distribution systems to minimize ground fault risks and with the advancements of LED lighting, and daylight harvesting, they all can economically be 120v loads.. so aside from electric reheat, (uggh) or a basin heater in a cooling tower, beyond Gen 2 chargers there’s no longer a need for a neutral. Regardless, this is a costly exercise for a condo association.

Wow, this sounds like it will be interesting. Curious if the 500 kva is a separate transformer just for this project? Assuming it will be three phase, but will it be 208/120 volt wye service, or have you somehow been able to arrange for a 240 volt delta service? Seems like utilities do not install much 240 volt 3 phase delta service anymore, but have seen older such delta services at older smaller industrial installations, either with or without the 120 volt center tap on one of the transformers.

 

[Eric33432]

Fascinating install! Has Tesla been willing to supply technical support or maybe even design help? As a computing professional, one thought that immediately comes to mind is that you're trying to do this on your "guest" network. I would probably want to provision a separate network with it's own security rather than try to coexist with other users. It would help if the UWC supported hard-wired network connections, but I don't think it does.

While 277v might make your install easier, I think that too many of your employees' cars wouldn't support it, but you surely know that.

On a separate topic, I had occasion to use some destination charging at a hotel last week. I didn't find out until later the next day that I had been charged for the session. There was nothing posted and nothing in the car to tell me I was being charged or how much. In fact, the car never showed the billing charge at all, I only saw it in a message sent to the app.

I didn't mind paying, and the rate was reasonable enough, but I kind of like to know these things ahead of time. Obviously, the hotel should have signage, but without a display on the wall connector, the car should have told me, ideally before I even plugged in. Tesla has some kinks to work out.

So the hotel got billing info out of the Tesla Wall Connector and plopped it onto your bill? Was it based on the kWh you used?

Next time I am at hotel I will ask if they charge. (Have not been charged yet anywhere.)

 

[davewill]

So the hotel got billing info out of the Tesla Wall Connector and plopped it onto your bill? Was it based on the kWh you used?

Next time I am at hotel I will ask if they charge. (Have not been charged yet anywhere.)

No, Tesla charged me through the app. It's a feature they've added to commercial installs of wall connectors fairly recently. Yes, it was based on kWh. in this case, it was $0.20 per kWh, which made it comfortably cheaper than Supercharging.

 

[Concerned]

Wow, this sounds like it will be interesting. Curious if the 500 kva is a separate transformer just for this project? Assuming it will be three phase, but will it be 208/120 volt wye service, or have you somehow been able to arrange for a 240 volt delta service? Seems like utilities do not install much 240 volt 3 phase delta service anymore, but have seen older such delta services at older smaller industrial installations, either with or without the 120 volt center tap on one of the transformers.

Yes it’s a dedicated 208Y/120.. with 2.1/2% taps that will allow us to have the nominal voltage for a typ 208 system a touch high.. and there will some minor 120 volt loads at the application: scada power supplies for the telemetry, waps for the network, power supplies for the cameras, and condensation strip heaters…. Red leg delta is exceedingly rare these days…. Even with using typical distribution equipment, the supply chain for power distribution equipment is long so I certainly don’t want to do something odd. We’ve had several Team’s meetings with Tesla folks and heretofore they’ve been wonderful to work with. My fundamental point on this thread is these deployments are very capital intensive and are considered amenities as there’s no real payback.. especially as we just pass along our purchase power rate to our employees.

 

[Concerned]

Fascinating install! Has Tesla been willing to supply technical support or maybe even design help? As a computing professional, one thought that immediately comes to mind is that you're trying to do this on your "guest" network. I would probably want to provision a separate network with it's own security rather than try to coexist with other users. It would help if the UWC supported hard-wired network connections, but I don't think it does.

While 277v might make your install easier, I think that too many of your employees' cars wouldn't support it, but you surely know that.

On a separate topic, I had occasion to use some destination charging at a hotel last week. I didn't find out until later the next day that I had been charged for the session. There was nothing posted and nothing in the car to tell me I was being charged or how much. In fact, the car never showed the billing charge at all, I only saw it in a message sent to the app.

I didn't mind paying, and the rate was reasonable enough, but I kind of like to know these things ahead of time. Obviously, the hotel should have signage, but without a display on the wall connector, the car should have told me, ideally before I even plugged in. Tesla has some kinks to work out.

Thus far Tesla has certainly been helpful in technical support, they’ve detailed the network coms for both the commercial transactions, their supervisory website and the group load sharing. While they have the ability to have a leader and five followers, we’ve elected to have groups of only 5 total wallpacks…. They aren’t designing, they’re fully describing.

As to guest network, I work for a large multi-national, with SLA’s for various tasks, using guest was not to rock the boat, we are specifically avoiding trying to set up something dedicated. Our other alternative was Starlink. But the internal management of reoccurring fees, and sustainability made it easier for us to just ask out IT partner to extend the guest network there.. and they’ve provisioning it to the MAC address level of the wall packs. We intend to sand box this to work out the wrinkles before it’s fully deployed, but at the same time, we are committed to this solution.

as to 277v, I agree it will make life easier for deployment in the future yet the universal wall pack doesn’t support that as J1772 doesn’t and we’d have to use Gen2 (which isn’t bad for Tesla drivers) and we’re trying to avoid user adapters…. As a Tesla driver, workplace chargers heretofore have all been J1772.. I certainly hope in time for migration to NACS / J3400 and am very excited about user supplied charging cables as people’s behaviors are abhorrent .. I’ve watched people unplug their vehicles and drop the charge handle on the pavement, then back up over them….

as a practicing power engineer, 277 brings some challenges in large applications with ground fault protection and I’d likely provide an isolation transformer anyhow just to isolate zone.. anyone who claims coordination can solve this hasn’t lived my life as I’ve seen lighting ballasts trip service mains because of slow thermal magnetic breakers. Sometimes the only breaker in the system that even has ground fault protection is the service main as nothing under 1200 amperes is “required”. I’ve stated elsewhere that I’ve intentionally tried to remove the neutral and solely distribute 480 3 phase power..

 

[Concerned]

So the hotel got billing info out of the Tesla Wall Connector and plopped it onto your bill? Was it based on the kWh you used?

Next time I am at hotel I will ask if they charge. (Have not been charged yet anywhere.)

In the application I’m deploying, we’ve purchased signs from Tesla that explicitly states that this is a fee based charger… the exact language I don’t recall… and I’ll post a picture eventually.. but what is charged is solely up to us. Tesla only wants one cent per kWh for their management fee. We will pass through our negotiated average rate and it’s actually cheaper that my home super off peak time of use, when the T&D is added in.

 

[Pricedm]

For me, significant benefits of using Tesla chargers for condo/multi-family garages is (1) ability to enable pay-per-use charging (2) Tesla Universal Wall Connector NACS/J1776 (3) ability for non-Tesla drivers to see real-time availability. All for the low overhead of $0.01/kWh admin fee Tesla charges.

 

[theflyer]

For me, significant benefits of using Tesla chargers for condo/multi-family garages is (1) ability to enable pay-per-use charging (2) Tesla Universal Wall Connector NACS/J1776 (3) ability for non-Tesla drivers to see real-time availability. All for the low overhead of $0.01/kWh admin fee Tesla charges.

Are your stations available to the public? How is realtime status handled if the stations are not public and not visible on Teslas charging map?

 

[Soul Surfer]

That is a really great setup! I should definitely talk to them about something like this given my outlet is almost as close as yours. I'd be happy to share it with another Tesla as well (there's sometimes but not always a model Y parked one space over).
So are they just happy to pay the bill or do you need to pay an extra fee since you're not being metered?

Nope not a dime. They recently installed 3 Flo® charging stations and lease them out privately to 3 other Tesla owners. That makes 4 Teslas now, in our complex. I got lucky and got “grandfathered” before the others. I suspect they pay an additional $60-100 Canadian on top of the parking spot.

 

[dakhlkt22]

The building manager told me to go ahead and use the outlet by my car so I did. Then 2 days later I was threatened with a huge fine if I did not stop using it. I stopped using it and put in a formal request with a proposal on how I'd pay for the energy usage. The condo board said they'd think about it and then didn't get back to me for months. Finally they said that I can't use it but they're working on a proposal to electrify all 100+ parking spaces in the garage.

Honestly their proposal is never going to happen, I think it's a stall tactic. They said they are working on it but there's been zero evidence over the last year.

I could sue them under Massachusetts state law which says I am allowed to charge my car in any safe, reasonable way in a HOA garage as long as I reimburse the HOA for the usage, but it seems too messy to do that. So I've just been charging elsewhere. Sad state of affairs.

Maybe ask for an update every month. If you don't follow up, they will just forget you are waiting.

If I were you, I would ask to speak to them. They likely have no idea what they are doing, and they are listening to proposals from vendors but they have no idea what the end user experience is like or what the norm is today. They may even be planning on installing CCS1 instead of NACS.

I think there are two scenarios: 1) you have 4+ spots in the garage somewhere that are not dedicated to specific unit owners which can become charging spots, or 2) you have to have a dedicated charger for your spot.

I think if they speak to you, you could recommend a simpler solution like installing 4-6 TWCs in a certain part of the garage if your garage has any parking spots that are not dedicated to specific unit owners. The board may have no idea that Tesla offers this simple relatively inexpensive option that will solve their charging needs for the first 10-20 EV owners. And once there is charging congestion (which might not happen for years), they can just install more TWCs.

If all of the parking spots are dedicated parking spots, I wonder if TWCs can still work or not. Maybe each TWC station can be shared by multiple parking spots, depending on the layout of the parking spots?

 

[J-a-x]

The garage already has 6 charging spots but those spots are shared between EVs charging and valet pick-up and drop-off (about half of the residents have a private parking spot and the rest have valet spaces). The problem with the community charge spaces is we're forbidden from charging there during morning and evening rush hour, meaning I can't let my car charge overnight without waking up at 6 am to move it, and then moving it back a few hours later. That and it's just really congested up there with cars coming and going all the time. Much simpler and better to just charge at my space given there's already an outlet there.

I just raised it with the board again yesterday (after 8 months of waiting) so we'll see what happens.

 

[dakhlkt22]

The garage already has 6 charging spots but those spots are shared between EVs charging and valet pick-up and drop-off (about half of the residents have a private parking spot and the rest have valet spaces). The problem with the community charge spaces is we're forbidden from charging there during morning and evening rush hour, meaning I can't let my car charge overnight without waking up at 6 am to move it, and then moving it back a few hours later. That and it's just really congested up there with cars coming and going all the time. Much simpler and better to just charge at my space given there's already an outlet there.

I just raised it with the board again yesterday (after 8 months of waiting) so we'll see what happens.

Maybe you could propose having the valets move cars that are still charging at 6 am to their assigned parking spots. The board likely does not realize the real world implications of their rush hour prohibition. This solution would require no new installations!

 

[Concerned]

For me, significant benefits of using Tesla chargers for condo/multi-family garages is (1) ability to enable pay-per-use charging (2) Tesla Universal Wall Connector NACS/J1776 (3) ability for non-Tesla drivers to see real-time availability. All for the low overhead of $0.01/kWh admin fee Tesla charges.

Thank You for sharing this, my Team and I were unaware that real time availability was active. This is fantastic news and will remedy multiple concerns for the users and our internal Ev charging administrator.

 

[J-a-x]

Maybe you could propose having the valets move cars that are still charging at 6 am to their assigned parking spots. The board likely does not realize the real world implications of their rush hour prohibition. This solution would require no new installations!

Not a bad idea, but that means I need to trust valet with my car and I'd persdonally rather just charge it in my parking space which already has an outlet. But for many in the building who don't have an outlet at their parking space, it would probably be a good plan because valet could reclaim the space if they need it (or just leave the charged car on a quiet day), and residents would be able to charge overnight before a big trip.

It's a big annoyance not being able to charge overnight because often I leave at 9 am on a trip where starting with 90-100% starting charge is convenient, but we are not allowed to charge between 6 am and 9 am, nor are we allowed to charge from 4 pm to 7 pm.
So after work the only reasonable time to start charging is at 7 pm and then I only get a max charge time of 5 hours before I go to bed while in reality I usually need 10-15 hours to get a full charge.

Another downside is that in order to punish people for leaving their cars in the valet spaces when they're not supposed to, the price doubles during those hours (60¢ instead of 30¢). I wonder if we implemented the plan you mentioned above if they'd consider not raising the rate as long as valet is able to move charging cars around. That makes it complicated though because they probably don't want to change the rate system since it earns the HOA money.

I think for simplicity the HOA probably wants to keep fining people via rates and not make valet do extra work.

Another thing - if we had faster chargers, say 10 kW destination chargers instead of our 6 kW setup that would reduce charging times and make it less important to charge overnight.

50% charge at 6 kW takes about 8 hours.
50% charge at 10 kW could be roughly half of that, so within the time I have between 7 pm and bedtime.

Even better would be a couple 50 kW DC charge stations but those are pretty expensive...

 

[J-a-x]

One more thought, while the idea of using my own outlet is convenient, its a simple 120V AC outlet so it would charge my car much slower than any other option, but not necessarily a deal breaker since I could charge for multiple days and nights in a row when I'm not driving much (working from home lets me do that). I'd probably still use the L2 chargers now and then in a pinch but would at least reduce the number of times I was causing congestion in the valet zone, free up the chargers for others who don't have a 120V outlet, and avoid the number of times people park next to me and ding me with their doors (a true hazard of leaving your car in a busy valet area).