Info from Tesla - 277v feed to Wall Connector (HPWC) - Which Cars Support It

[miimura]

Thanks, your posts are always much appreciated.

Am I wrong in thinking that the one 277v hot wire fed one of the three on-board charger boards ?
I was imagining that hooking up all three 277v phases, one to each circuit board that can handle 48 Amps, would give an RMS of 480 volts

I don't know or understand the power limitations or what would be involved in bumping that power rating higher. I was wondering about a world where the power rating is not the limiting factor, and came up with 0.48 kV * 48 Amps for the 3 circuit board architecture.

Nonsense ?

Yes, for a North American Tesla, this is nonsense. The charge port only has two poles and the sub-modules are all in parallel. If you take them out of parallel connection, each one can only take 1/3 of the current. Now, if you had a European or Oceanic Tesla with a Type-2 charge port, then you could connect 3 phases and neutral because there are 4 poles with 16A per phase. However, you would have to check what the voltage limits are. EU power is nominal 230Y400V, so 277 is 20% over nominal. If we assume that the OBC components are the same between the single phase and 3 phase and the NA cars can accept 277, then you should also be able to charge a European car at 277Y480V, but the power is the same as US: 277V * 3ph * 16A = 13.3kW

I'm not saying that a 23kW OBC is not practical, I'm just saying that you can't do it with the OBC in the 3/Y. The dual charger in the Classic Model S was 22kW in Europe. 230V 3ph 32A = 22kW. Light passenger cars really have no need for an OBC that big. Pickups and medium commercial vehicles would be well served with OBCs of that size though.

 

[Tress]

. Light passenger cars really have no need for an OBC that big. Pickups and medium commercial vehicles would be well served with OBCs of that size though.

A large OBC makes sense in areas without L3 chargers and you don't want to spend all afternoon. Look up Fredericksburg Texas, Barons vineyard has a 80 amp charger. It was perfect ... 1 bottle of wine = 160 miles. It was the one option I missed moving from my MS 2014 to a 2019 model.

 

[SageBrush]

A large OBC makes sense in areas without L3 chargers and you don't want to spend all afternoon. Look up Fredericksburg Texas, Barons vineyard has a 80 amp charger. It was perfect ... 1 bottle of wine = 160 miles. It was the one option I missed moving from my MS 2014 to a 2019 model.

Yep. Rural people know this issue all too well. As for what Tesla/society should do to optimize money spent, that is a lot trickier. DC chargers are expensive but then cars do not need more expensive on-board chargers.

 

[rypalmer]

35% more power per amp will become even more attractive as the cost of copper climbs. Cost savings on the transformer side too... The charging speed thing is just a nice bonus.

 

[EfficientWatts]

Good news, I’ve successfully charged my model Y using my ~277 volt line. It’s on a 20 amp breaker, so I’m only able to get 16 amps usage. But my charging time went from 6 mil/hour on a 110 volt 16amps outlet to 16 mil/hour at 270 v 16 amps.

Interestingly my voltmeter read 280 volts from the outlet. But 2022 model Y’s onboard computer says only 268-270 volts input. Maybe the Mobile connector assessed and negotiated with the outlet and determined 270 v is more stable.

View attachment 786564

One cannot "negotiate" with a standard outlet to provide less voltage, the voltage will be whatever it is.

Under load voltages will naturally drop. One way you can test this is to reduce the input current and the voltage will rise. You can also not charge but turn on the AC while plugged in and the car will draw current (but less than charging if ac is set to be a low setting) and you'll see a higher voltage.

 

[21T3slaY]

I contacted Tesla's tech support and a rep said the Gen 3 will cut off at 264v. So I got a Gen 2 and wired it up to 277 and it's working great. Thanks for everyone's posting on here.
Next, I'd love to see a simple DC charger that works with a solar inverter so there is no inefficiencies in the conversion process from DC to AC back to DC.
I'm estimating a 10-25% loss. It would be great because it would only charge when I'm producing power instead of borrowing from the power company just so I can pay twice as much as they pay me.

I did the same. The Gen3 charger LED would go to red when connected to a 277v ckt and the web interface displayed an error about the voltage being too high. I installed a Gen2 charger (which is a pain the backside compared to a Gen3 BTW) and now I'm charging at 8.5kW on our standard range model 3 which is supposedly limited to 7.7kW. The charging amperage drops from its max of 32A to 30A and my measured voltage is 281V.

 

[5Mach]

Hello! I have a Gen3 18' Wall Charger for Sale- $485.00. Pristine & New in Box. Never used or installed, never un-wrapped. I bought the unit because the 24' were not available at the time. Purchased as a Xmas present for myself 12/20. I would love to sell this one and buy the 24' model. I can work on Shipping proposal to support someones interest. I live in the Chicago area and can deliver to someone interested. Thanks!!

 

[KD4MNI]

This thread has gained increased relevance with the 11/2022 publication of the NACS (SAE J3400) specifications (and their subsequent wide adoption), which include support for EV Level 2 ac charging at up to 80A@277Vac (J1772 is specifically limited to 80A@240Vac). In North America, commercial sites are typically provisioned with single-phase 277Vac power (from 3-phase 400Vac commercial power service). This ~15% increase over nominal 240Vac mains voltage could lead to corresponding reductions in Level 2 ac charging times. I expect to see a new crop of NACS-compliant Level 2 EVSEs that are explicitly designed for use with commercial 277Vac power.

It's good for Tesla Model 3/Y drivers to know that they can safely, confidently charge their BEVs using NACS-equipped EVSEs in commercial settings provisioned with 277Vac single-phase mains voltage (thanks to the information from Tesla at the start of this thread).

It's surprising to read that the (current) Gen 3 Tesla HP Wall Connector isn't designed for 277Vac single-phase operation. Clearly there are some units (installed at dealerships, businesses, etc) that are configured to support higher operating voltages (>240Vac).

Likewise, it's surprising to read that some late-model (2018+) Tesla Model S/X BEVs cannot reliably charge from 277Vac (sensitive to overvoltage), even though the Model 3/Y onboard ac chargers reportedly have no issues.

I wonder if J1772 (CCS-1) will be updated to accommodate 277Vac single-phase charging. I suppose there are backwards-compatibility safety issues, although I would expect these to be minor. This is an obvious example of the numerous fundamental shortcomings of J1772/CCS-1.

www.tesla.com/support/charging-product-guides#NACS-resources (links to NACS/SAE J3400 specifications)

 

[SageBrush]

In North America, commercial sites are typically provisioned with single-phase 277Vac power (from 3-phase 400Vac commercial power service).

480V 3 phase supply is 277V single phase in Wye

 

[mongo]

This thread has gained increased relevance with the 11/2022 publication of the NACS (SAE J3400) specifications (and their subsequent wide adoption), which include support for EV Level 2 ac charging at up to 80A@277Vac (J1772 is specifically limited to 80A@240Vac). In North America, commercial sites are typically provisioned with single-phase 277Vac power (from 3-phase 400Vac commercial power service). This ~15% increase over nominal 240Vac mains voltage could lead to corresponding reductions in Level 2 ac charging times. I expect to see a new crop of NACS-compliant Level 2 EVSEs that are explicitly designed for use with commercial 277Vac power.

Boosting mains voltage doesn't change the power limit of the vehicle's onboard charger. The EVSE (wall connector) also doesn't impact the vehicle's voltage limit. 208V may hit current based power limits vs 240V, but 277V doesn't increase the maximum power (though it would reduce current requirements on conductors).

As far as NACS, the standard connector is rated for 240V AC nominal.

It's surprising to read that the (current) Gen 3 Tesla HP Wall Connector isn't designed for 277Vac single-phase operation. Clearly there are some units (installed at dealerships, businesses, etc) that are configured to support higher operating voltages (>240Vac).

Why is that surprising? 208V and 240V are the more common voltages, plus not all the cars support it. If needed, one can get 240V off a high leg 480 delta. Or add a small buck transformer to go from 277V to 240V ($1k).

I wonder if J1772 (CCS-1) will be updated to accommodate 277Vac single-phase charging. I suppose there are backwards-compatibility safety issues, although I would expect these to be minor. This is an obvious example of the numerous fundamental shortcomings of J1772/CCS-1.

FYI, CCS-(1/2) is a combined plug and only for DC, J1772 on its own is the Level 2 AC standard. As you mention, that would break compatibility with 240V max vehicles. That's not minor, those EVSE would be unusable (and require additional signalling or keying)

 

[SageBrush]

If needed, one can get 240V off a high leg 480 delta

Huh. Are you sure about that ? If I have this right, and the 'B' leg is the high leg, then A-N or C-N would be 240V

 

[mongo]

Huh. Are you sure about that ? If I have this right, and the 'B' leg is the high leg, then A-N or C-N would be 240V

Yeah, a high leg delta configuration (as opposed to corner grounded) with connections from N-A or A-C, but not N-B.

 

[wws]

This thread has gained increased relevance with the 11/2022 publication of the NACS (SAE J3400) specifications (and their subsequent wide adoption), which include support for EV Level 2 ac charging at up to 80A@277Vac (J1772 is specifically limited to 80A@240Vac). In North America, commercial sites are typically provisioned with single-phase 277Vac power (from 3-phase 400Vac commercial power service). This ~15% increase over nominal 240Vac mains voltage could lead to corresponding reductions in Level 2 ac charging times. I expect to see a new crop of NACS-compliant Level 2 EVSEs that are explicitly designed for use with commercial 277Vac power.

It's good for Tesla Model 3/Y drivers to know that they can safely, confidently charge their BEVs using NACS-equipped EVSEs in commercial settings provisioned with 277Vac single-phase mains voltage (thanks to the information from Tesla at the start of this thread).

It's surprising to read that the (current) Gen 3 Tesla HP Wall Connector isn't designed for 277Vac single-phase operation. Clearly there are some units (installed at dealerships, businesses, etc) that are configured to support higher operating voltages (>240Vac).

Likewise, it's surprising to read that some late-model (2018+) Tesla Model S/X BEVs cannot reliably charge from 277Vac (sensitive to overvoltage), even though the Model 3/Y onboard ac chargers reportedly have no issues.

I wonder if J1772 (CCS-1) will be updated to accommodate 277Vac single-phase charging. I suppose there are backwards-compatibility safety issues, although I would expect these to be minor. This is an obvious example of the numerous fundamental shortcomings of J1772/CCS-1.

www.tesla.com/support/charging-product-guides#NACS-resources (links to NACS/SAE J3400 specifications)

While at it, whatever Standard NACS develops into should should allow 120V AC charging at least up to 24 amps. This would cover TT-30 charging at campgrounds/RV parks. Currently, so to speak, J1772 only defines a 16 amp max at 120V. And many non-Tesla EVs are hard coded to 12 amps max.

 

[mongo]

While at it, whatever Standard NACS develops into should should allow 120V AC charging at least up to 24 amps. This would cover TT-30 charging at campgrounds/RV parks. Currently, so to speak, J1772 only defines a 16 amp max at 120V. And many non-Tesla EVs are hard coded to 12 amps max.

Level 1 is typically 16A max at 120V (20 Amp outlet at 80%), but that is not a J1772 limit. It advertises currrnt limits, not voltage.

 

[wws]

Level 1 is typically 16A max at 120V (20 Amp outlet at 80%), but that is not a J1772 limit. It advertises currrnt limits, not voltage.

I think the confusion is that many associate L1 with 120V charging, and L2 with [208, 240, 277]V charging. Perhaps the SAE or whoever eventually defines the Standard could differentiate L1 and L2 by power level (e.g., greater or less than 2 kW). And also specify that 120V is allowed all the way to whatever the limits of the on-board charger are. Somehow they need to encourage the 24 amp 120V case for TT-30 (and variants of L5-30 for marinas and generators) - because some manufacturers are not getting it right.

 

[Fiver]

I think the confusion is that many associate L1 with 120V charging, and L2 with [208, 240, 277]V charging.

Yes. I've basically always thought 120v wall outlet charging as L1. But then again I have used my TT-30 adaptor to charge at a campground before and know it's possible to charge at higher 120v amperage also (albeit rare).

So what is the actual definition? Is any 120v charging L1 or is it just what a standard North American household (15-20amp 120v) can output? I say North American as the voltage the EU runs in homes is what I consider L2 charging.

 

[mongo]

Yes. I've basically always thought 120v wall outlet charging as L1. But then again I have used my TT-30 adaptor to charge at a campground before and know it's possible to charge at higher 120v amperage also (albeit rare).

So what is the actual definition? Is any 120v charging L1 or is it just what a standard North American household (15-20amp 120v) can output? I say North American as the voltage the EU runs in homes is what I consider L2 charging.

Article that links in SAE definitions
Electric Vehicle Charging Levels Explained

 

[Fiver]

Is that article still accurate? It's 8 years old and says that the max DC charging speeds are 120kW.


That said in broad terms the article does say basically that anything 120v is L1 and L2 is 208-240v, even if it fails to mention 120v charging options above 16amps or 277v charging at all. It does state that any 208/240v/DC charging source under 90kW L2. Lumping DC in there is interesting if true.

I've always kept it simple in my mind: All 120v is L1 regardless of amps. All 208/240/277v is L2 regardless of amps. Anything that bypasses the onboard charger and dumps DC power straight into the battery is L3.

/edit. Basically Europe never has to deal with the misery of L1 charging, lucky bastards .

/edit 2. I've never heard or seen anything 480Y in regards to charging a car, although iirc a single 480Y leg is 277v.

 

[mongo]

I've always kept it simple in my mind: All 120v is L1 regardless of amps. All 208/240/277v is L2 regardless of amps. Anything that bypasses the onboard charger and dumps DC power straight into the battery is L3.

Sounds right to me. (Not that it seems like the levels really matter)