Car Charger Diversity?

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theophilus88

Professional Architectural Engineer
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St. Louis, MO
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Professional Architectural Engineer
For my project, we are installing for (4) 100A car chargers. Is there a certain level of diversity I can apply to these car chargers? Is there an NEC section in regards to this? How much amperage does a car charger generally use? Also, sorry for the lack of information, all I was told is that there will be (4) 100A car chargers. Thanks in advance for any advice.
 
theophilus88 said:
For my project, we are installing for (4) 100A car chargers. Is there a certain level of diversity I can apply to these car chargers? Is there an NEC section in regards to this? How much amperage does a car charger generally use? Also, sorry for the lack of information, all I was told is that there will be (4) 100A car chargers. Thanks in advance for any advice.
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Just quoted some for a major freight delivery company. Their specs said the charger is 100 amp set for continuous 80 amps. Might want to check the service capacity too, as the building this customer has, would push the service to over 80% of its present capacity.
 
You need to know what the exact specs are. And if it’s a charger or an EVSE. A charger supplies DC, while an EVSE passes AC voltage to the car’s built in charger. People mistakenly call EVSEs “chargers” quite frequently.

There is no allowance for diversity for either in the NEC AFAIK.
 
retirede said:
You need to know what the exact specs are. And if it’s a charger or an EVSE. A charger supplies DC, while an EVSE passes AC voltage to the car’s built in charger. People mistakenly call EVSEs “chargers” quite frequently.

There is no allowance for diversity for either in the NEC AFAIK.
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Correct, usually the DC chargers have a 200 amp AC input, unless 480 volt.
 
retirede said:
You need to know what the exact specs are. And if it’s a charger or an EVSE. A charger supplies DC, while an EVSE passes AC voltage to the car’s built in charger. People mistakenly call EVSEs “chargers” quite frequently.

There is no allowance for diversity for either in the NEC AFAIK.
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And I can't see why there would be. Depending on the charger level and the charge state of the EV's batteries, it's certainly possible, if not probable, that they'd all be charging for more than three hours.
 
Maybe it should be a new thread, but I was just curious what these 100 amp chargers do to the power factor?
 
gadfly56 said:
And I can't see why there would be. Depending on the charger level and the charge state of the EV's batteries, it's certainly possible, if not probable, that they'd all be charging for more than three hours.
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at full load?

It is certainly likely that all of them will be on at the same time on a regular basis.
 
petersonra said:
at full load?

It is certainly likely that all of them will be on at the same time on a regular basis.
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I'm guessing that each charger is on its own 100 amp breaker, but I think I get your point, they're not going to be pulling 100 amps, or even 80. I took a quick look at the JuiceBox Pro charger, and it looks like it's 40 amps at 240 VAC. Whatever it is, even at Level 2 what I've seen around the 'Net suggests 4-5 hours to charge, so, considered continuous, and I'd figure folks hang it up more or less at the same time every day, so, no diversity.
 
Thanks guys, these responses definitely help! I just requested more info on the specs from the GC, so I'll keep you all posted.
 
Here's the information they gave me. It kind of only leaves me with more questions... Why would they say 60A min, 100A preferred for the breaker size? How do I assume my demand load on these things?
 

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theophilus88 said:
Here's the information they gave me. It kind of only leaves me with more questions... Why would they say 60A min, 100A preferred for the breaker size? How do I assume my demand load on these things?
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I don't know what you mean by demand load. As I see it you have to count all of them at 100%.
 
theophilus88 said:
Here's the information they gave me. It kind of only leaves me with more questions... Why would they say 60A min, 100A preferred for the breaker size? How do I assume my demand load on these things?
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The breaker size has little to do with the actual load. You need to get a spec sheet for the specific charger being installed to determine how much current it will draw. My guess based on the minimum 60 Amp rated CB would be no more than 50 Amp. So likely you are adding about 200 Amps of load to whatever source is feeding the panel this is coming from. I would be unsurprised if this exceeded the allowable calculated load.
 
petersonra said:
The breaker size has little to do with the actual load. You need to get a spec sheet for the specific charger being installed to determine how much current it will draw. My guess based on the minimum 60 Amp rated CB would be no more than 50 Amp. So likely you are adding about 200 Amps of load to whatever source is feeding the panel this is coming from. I would be unsurprised if this exceeded the allowable calculated load.
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More like 48, but close enough (60 x 0.8 = 48).
 
Barbqranch said:
Maybe it should be a new thread, but I was just curious what these 100 amp chargers do to the power factor?
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Unless they are conventional chargers then it is usually distortion power factor rather than displacement power factor.
 
From the document, these are EVSEs, not DC chargers. An EVSE is just a slightly smart switch (for the car to tell the EVSE to turn on the AC power) that advertises a maximum allowed current level. When a car is plugged in, it will charge at the lesser of the car's internal charger current limit, or the EVSE's advertised current limit. The one model referenced in the document, Blink Fast IQ 200, is rated for up to a 100 amp circuit. EVSEs are continuous loads per Article 625, so with a 100 amp circuit the Blink Fast IQ 200 can advertise 80 amps charging. Not many cars can currently use 80A AC for charging, most will have a lower rating on their onboard charger (usually at least 30A).

EVSEs typically can be dialed down internally when put on a smaller circuit, so that explains the 60A to 100A comment. Also note the comment that the dual port charger can be configured with two separate circuits or a shared circuit; in the latter case, the advertised current for each port will vary depending on what is being drawn on the other port, so that the total circuit capacity is not exceeded. Note further "The agreement will specify the applicable wiring configuration to be installed as part of the make-ready." So there should be an additional specification for the site.

As to the power factor, it depends on the car and its onboard charger, it may vary.

Cheers, Wayne
 
wwhitney said:
From the document, these are EVSEs, not DC chargers. An EVSE is just a slightly smart switch (for the car to tell the EVSE to turn on the AC power) that advertises a maximum allowed current level. When a car is plugged in, it will charge at the lesser of the car's internal charger current limit, or the EVSE's advertised current limit. The one model referenced in the document, Blink Fast IQ 200, is rated for up to a 100 amp circuit. EVSEs are continuous loads per Article 625, so with a 100 amp circuit the Blink Fast IQ 200 can advertise 80 amps charging. Not many cars can currently use 80A AC for charging, most will have a lower rating on their onboard charger (usually at least 30A).

EVSEs typically can be dialed down internally when put on a smaller circuit, so that explains the 60A to 100A comment. Also note the comment that the dual port charger can be configured with two separate circuits or a shared circuit; in the latter case, the advertised current for each port will vary depending on what is being drawn on the other port, so that the total circuit capacity is not exceeded. Note further "The agreement will specify the applicable wiring configuration to be installed as part of the make-ready." So there should be an additional specification for the site.

As to the power factor, it depends on the car and its onboard charger, it may vary.

Cheers, Wayne
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I thought the "make-ready" document specified separate runs to dual port chargers.

A separate conduit or pair of conduits shall be run from the source electric panel to each of the pedestals included in the agreement. Where 2 circuits are required to feed the pedestal, each circuit should be run in a separate conduit.

But it does also say:

The dual-port charger can be configured to share a single circuit or to have dedicated circuits for each port.
 
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