EV charging stations power

[Tainted]

They are planning on installing EV charging stations in a apartment building garage.

A client wants to know how many EV charging stations can be on a 400A 3-phase 208 volt switch.

How many kw typically is per charging station?

 

[wwhitney]

If you're talking the typical "Level 2" (J1772, regular 208V or 240V AC 2-wire), those can be set up to 80A, with 30A/32A and 40A being common.

For "Level 3" (DC Fast Charge), that's 25 kW - 200kW, with 50kW and 100kW common. But those are nominal output ratings at 500V DC (IIRC), so I expect the corresponding input ratings are higher.

Cheers, Wayne

 

[Tainted]

If you're talking the typical "Level 2" (J1772, regular 208V or 240V AC 2-wire), those can be set up to 80A, with 30A/32A and 40A being common.

For "Level 3" (DC Fast Charge), that's 25 kW - 200kW, with 50kW and 100kW common. But those are nominal output ratings at 500V DC (IIRC), so I expect the corresponding input ratings are higher.

Cheers, Wayne

Typically in apartment buildings which levels do they install? I would imagine level 2 correct me if I’m wrong. How many kw typically in apartment buildings do level 2 consume?

 

[wwhitney]

Typically in apartment buildings which levels do they install? I would imagine level 2 correct me if I’m wrong. How many kw typically in apartment buildings do level 2 consume?

I think 30A Level 2 would be typical, and Level 3 would be pretty rare for an apartment building. For 30A 208V, 6.24 kW, etc. No losses--Level 2 EVSE is just a slightly smart switch that can tell the EV how much current is available and open and close a contactor.

Basically it's up to the customer to choose more stations at a lower power (20A, say), or fewer stations at a higher power (40A or 50A). There are also networked solutions so that each station can be higher power, but if an overall cap is hit, then all the stations throttle back as necessary.

Cheers, Wayne

 

[wwhitney]

Also, note that breakers on feeders supplying EVSEs need to be sized for 125% of the EVSE continuous current (with no exception for 100% rated breakers; I think that's an oversight). If you have a 400A 3 phase breaker as your supply, you can only use 320A for EVSEs. Divide by sqrt(3), and that's 184A available per phase (pair of line conductors). So you could do 6 * 3 = (18) 30A EVSEs on that 400A 3 phase breaker.

Cheers, Wayne

 

[retirede]

The client needs to do some analysis before asking that question:
Will they be for tenant use only?
Pay to charge or included in the rent?
How many apartments and what is the typical % who have an EV?
How far is the typical commute for apartment dwellers in the area?
What are future plans?

Then he can get an idea how many he needs and can size accordingly.

I have never seen nor heard of an apartment building with level 3 DC charging. Always L2 (or just a receptacle). 5 to 7KW is pretty typical for public L2.

 

[Tainted]

Also, note that breakers on feeders supplying EVSEs need to be sized for 125% of the EVSE continuous current (with no exception for 100% rated breakers; I think that's an oversight). If you have a 400A 3 phase breaker as your supply, you can only use 320A for EVSEs. Divide by sqrt(3), and that's 184A available per phase (pair of line conductors). So you could do 6 * 3 = (18) 30A EVSEs on that 400A 3 phase breaker.

Cheers, Wayne

Super duper helpful thank you!

 

[Jraef]

I have never seen nor heard of an apartment building with level 3 DC charging. Always L2 (or just a receptacle). 5 to 7KW is pretty typical for public L2.

I can imagine that insurance companies would have some concern for a bunch of level 3 EV chargers running in the basement garage of an apartment complex… The car batteries get pretty toasty when being charged by L3 chargers.