NACS/J3400's Support For 277V Charging Is A Huge Deal and Here's Why
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- Опубликовано: 1 июн 2024
- Most single family homes in America have 240V electricity available for EV charging, but oddly enough most of our workplaces, hotels, schools, churches, and even larger multi-tenant buildings don't have 240V available and that's exactly why the SAE J3400 charging standard (NACS) supports 277V charging. By supporting 277V in addition to 240V (and 208V), the new charge connector will allow faster charging at work and it'll make those workplace EV "chargers" less expensive and faster to install. It's a high voltage win-win-win with just one tiny problem: Nobody but Tesla supports it at this time. Join me as I dive into J3400 and say why I think 277V charging is more important than DC fast charging.
Note: If you want to go deeper down the rabbit hole, 120/240V split phase AC is 120V RMS (root mean square), not peak. The peak voltage is actually 170/340V, but for reasons that I'll let you google, we use the RMS value colloquially and act like that's actually the peak. An earlier cut of this video took a deep drive down that long road but our editing staff fell asleep so we decided to leave that on the cutting room floor.
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You can bet that as soon as we can get our hands on a 277V NACS EVSE, we're going to install one! Also: If you want to go deeper down the rabbit hole, 120/240V split phase AC is 120V RMS (root mean square), not peak. The peak voltage is actually 170/340V, but for reasons that I'll let you google, we use the RMS value colloquially and act like that's actually the peak. An earlier cut of this video took a deep drive down that long road but our editing staff fell asleep so we decided to leave that on the cutting room floor.
Tesla wall connectors ALREADY support 277v and I believe all Model3/Y and most s/x support 277
@@olemissjim277 volt support was always iffy on Tesla vehicles. The older wall connector supported it officially, but the on board charger has over voltage protection that trips just a bit higher than 277V, so it can be flaky if your voltage is even slightly high. As far as I know, the newer Tesla wall connectors don't officially support 277V.
Hopefully this changes with official support in NACS.
@@BrianCairns As I recall, there was a "Legacy" DIP switch that had to be set in order for the HPWC to accept 277 V. However, regardless of whether they were set properly, the older Tesla units were considered low quality/unreliable, so the internals were likely to need to be repaired/replaced even when operating within those specs.
@@olemissjim The older destination chargers explicitly support it, current destination chargers say 240V max so 277V support is best described as "unofficial" but Tesla has said directly that Model 3/y fully support 277V.
@@EVBuyersGuideIf my memory serves me correctly the v2 Supercharger cabinets is a stack of Model S/X onboard chargers and the cabinet input voltage is 277/480 volt three phase. So, technically it can handle 277 volts without any issues.
I have to say that was quite an ingenious way to keep costs low by using what they already had by ganging them up together with a little bit of power electronics and voilà you got yourself a high power DC fast charger.
THIS is why I watch Alex on autos. No other car journalist would think about, let alone make a 14 minute video about a topic that (while somewhat niche for this platform) is such a big deal in the real world. Love the detail you go into as well
yeah. this is an excellent video. I just finished constructing a 3 phase apt building and I did not know this was an option. Tesla just has more common sense than allot of other companies. Build in 277 from the start, make all those light poles available all over America.
*tries to remember which videos Out of Spec Reviews and Transport Evolved have put out recently*
What is Alex on Autos? This channel has a different name.
Old arse news now. Must be a slow news day
I now understand why 3 phase provides 208v instead of 240v. It’s been explained to me before but now I finally understand.
Thanks
US 3 phase is also different than in EU 😅 you have 240V L-N, but use 208V L-L, while Europe mostly uses 240V L-N and you specifically need to change arrangement of connection to electric motor to ignore neutral wire.
@@uosiumen The US generally doesn't have 240V line-to-neutral, except in very special-purpose applications like data centers. We have 240V line-to-line and 120V line-to-neutral on single phase services (split-phase), typical of residences. We have 120V line-to-neutral and 208V line-to-line for lower power applications of 3-phase, usually apartments and light commercial applications. Usually each dwelling unit gets two of the three phases, and the neutral, so their higher voltage loads aren't as high as it is for a single/duplex residence.
The 277/480V 3-phase is typical of large commercial and industrial applications, which usually has a small transformer for 120/208V for a minority of the loads like receptacles. Some industrial applications use 347/600V 3-phase.
And there actually is a 120/240v delta system as well. But you have the high leg that is 208v L-G but you can't use it for that. I know that ChargePoint EVSE cannot be used from one of the phases to that phase (should be L2 (but commonly called "B" phase)). That stinger can make electronics release their magic smoke.
@@patrickmay8261 The high leg B-phase is useable in theory for a line-to-neutral load, but it comes with pitfalls to make it happen in practice. Most of the time, you'd prefer the 240V circuits anyway, on this system.
Most single pole breakers are slash-rated for 120/240V, which means they require 120V to ground nominal. This means they can serve 120V phase-to-neutral loads, but not high leg B-phase loads.
In concept, you could use a multiple breaker that is straight rated for 240V, and abandon the other poles. Another solution is to use a 277/480V panelboard. Both of these have the problem of sending mixed messages to future users.
You can think of it this way: For three phase, the line to line voltage (208) is the line to neutral voltage (120) times the square root of 3, or 120 * 1.732 = 208. For single / split phase, the line to line voltage (240) is the line to neutral voltage (120) times the square root of 4, or 120 * 2 = 240. Six phase is out there too but let's not go there. 6 phase is super rare.
Thanks! I never quite understood how we got 208 volts from 3 phase until this video. Also I love that you have a vintage macintosh on your desk!
Was not expecting an electrical engineering crash course in this video. Nice job!
I actually hadn’t considered how big of a deal this is. 277 is so similar to 240 in effectiveness for the user - but 277 is so much simpler and cheaper to install for commercial or industrial sites.
Love the use of a Mac SE/30 to demonstrate what uses a 120v plug 👍😆. I loved this video, thought it was really helpful as someone who understands EVs and the basics of charging but am by no means an electrician
I should have used a shotgun mike to add in the floppy disk noises LOL
I rarely post comments, but I really wish you were my Circuits professor when I took that class all those years ago, Alex. This was great, thank you for this explanation.
As a recently retired Electrical Power Generation Engineer who worked for Square D, Leviton, Cummins Power Generation, and T&B this was well explained. There is one issue that I ran across in Denver at a police/emergency station where they designed a step-down xfmr off one phase of the 480/277-volt panel to feed one charger. After the installation, they wanted six chargers. Sometimes a dedicated 480V delta to 120/240V delta EV charging xfmr is easier to balance from the main 480/277 volt panel which has a lot of 277 volt lighting loads.
You have to be careful with that stinger though. ChargePoint chargers cannot be used with the stinger phase. Probably the way they check for ground faults could end up sending the stinger to ground and not being able to handle it.
@@patrickmay8261 I am not following your thought process
Highlight of my day is Alex validating my nerd credentials by sticking with the video. Very informative and useful, thanks!
Yay for power nerds!
I can’t believe I have a degree in Computer Engineering, took classes in power transmission, but learned way more in this video.
Very useful. I've been peripherally involved with electrical service in my work for years and this was a good explanation of how American electrical service works and the differences between residential and electrical service. I don't think it was too deep into the weeds at all.
This was fun. I am an Electronics Technician and spent 20 years working on very low power DC devices used in potentially explosive environments like oil and gas facilities. Now I work for a company that does a lot of electrical safety testing so I am in the world of AC and anything from single phase 120 VAC to 3 Phase 480. It's been a (safe mentored) learning experience and interesting wrapping my brain around power delivery. Great video.
Excellent presentation, very educational and definitely not too deep. As someone who has cross shopped home and restaurant cooking appliances for my kitchen I've encountered the 208/240V conundrum. Glad to have the power differences explained so clearly.
It is typically heating elements that are more flexible that can run on either voltage, while the motor and controls that are more voltage-sensitive that run on the 120V. This comes at a cost of less power to the heating element, since it only runs at 75% of its power.
I’ve been advocating this for years
277v is one leg of a 480v transformer. So a one 3 pole 480v 20A would have very little voltage drop, an inexpensive
L1 N G to a EVSE would be
20A x 277v = 5.5kW
Vs the less efficient 3p 208, so you need L1 and L2 plus G and with volt drop it’s around 201v.
20A x 201v = 4kW.
So you your EV is charging at 37% faster with less loss and the transformer doesn’t have to deal with wacky L1 L2 and L2 L3 and L3 L1 balancing
For cars with 32A max it's even better
32A x 201v = 6.4kW
32A x 277v = 8.9kW
Or 48S
Or
48A x 201v = 9.6kW
48A x 277v = 13.2kW
Residential is 240v. So it's still a big improvement at 277v and no phase balance issues
Saves SO much money on copper and transformers and line loss, while boosting charging time ~20% to 40%
Large parking lots, like malls, apt, condos, and airports could deploy super inexpensive 20A NACS stalls at 277v and be close to the speed of their 208v 30A at dramatically lower deployment cost
You remain the best at razor sharp accurate facts. Thank you for being such a power nerd.
Great info, thanks! 277V will be important in the near future.
Interestingly, Tesla originally supported 277V charging, but when they switched On-Board Chargers on the model S/X, they became less reliable so they officially removed support from all documentation. I think the refresh S/X are now using the same OBC as the 3/Y? I don't know now.
Since the introduction of 3/Y, their onboard chargers can handle 300V max and many users on the forums have shown it working, as the Tesla wall connector also (unofficially) works on 277V. The OBC is power limited though, so most were only seeing 45-46A.
I found a free public Tesla Wall Connector in a parking garage that my 2016 Model S was unable to charge at. But my mom's 2023 Model S and other people's Model 3's were able to charge on it just fine. I'm wondering if what's going on here is that the Tesla Wall Connector is configured at 277V and my car's OBC doesn't support it.
@@The_TermiGator Too bad you didn't look to see what your mom's S was charging at. But yeah, there was a range of years where the S/X won't accept more than 250V.
This is WONDERFUL. One of the best simple-but-deep explanations I've heard about all of this stuff. 277V at a parking lot means the most popular EVs (Tesla 3 & Y) get a FULL charge on their long range packs in about 6-6.5 hours. Note how unlikely that will be. Most users charge to 80% and most don't drive in on 0%. In a typical scenario a 2-4 hr visit may be enough to cover a whole week's worth of driving. Those extra volts do count an awful lot. For those without at-home charging, getting this J3400 standard in is more impactful than many realize. An hour in either of those Teslas is 36-50 miles worth of driving.
You have earned a new subscriber immediately!
I really appreciate that final point about why a “Global” connector is not only never going to happen, it’s just a bad idea. We have totally different power systems in the US vs Europe, and what works best for the US would be awful in EU. A “universal” charging connector would be massive and wasteful.
Yep you would have to change AC multi phase standard for the entire infrastructure first before you can do a universal charger connector. No clue why you would even want to do that.
Yep you would have to change AC multi phase standard for the entire infrastructure first before you can do a universal charger connector. No clue why you would even want to do that.
I am just realizing this is probably a drag on the resale value of electric cars. You can’t just send them off to any country and sell them there, they can only be sold in a region with equivalent electrical systems
To be fair, a NACS-like connector that simply doubled the pins while making them half as big would work worldwide. In 3-phase countries, it would be wired L1+L2+L3+unused/N for all phases or L1+unused+unused+N for one phase, in split-phase it'd be L1+L1+L2+L2 (or L1+L2+unused+unused/N) for 240V or L1+unused+unused+N for 120V, on DC plus+plus+minus+minus.
@@HenryLoenwind We are lucky in the 50 HZ world to only have 2 voltages to deal with. Electricity is delivered along the street from a single remote sub-station as 3-phases at 400 volts.(+-5%) using 4 physical wires. ie. a neutral wire and 3 phase wires. The voltage from neutral to any phase is 230v. This power is sent to most homes from the street using a neutral wire and one of the phase wires giving ordinary homes a single phase at 230v. Alternate houses along the street and connected to different phases in the street to balance the load. We do not use split phase.
Larger premises, or houses requiring 400v 3-phase get a neutral and all three phases. This gives them access to both 230v and 400v.
This simpler approach is why NACS will not be used in the rest of the world.
Great explanation! The downside of electrification starting in the US was starting to build out the grid before they knew what made the most sense. Europe's system is definitely superior. Glad to see EVs are making the best of it!
It depends on what you’re after. 240v split phase has an intrinsically greater safety margin which is what they were after in the early 1900s
This is what I really appreciate about your channels, lots of "deep" facts and backgrounds, not just opinions.
In the UK most home supplies are single phase and max out at 32A so charge at 7.4kW on 230V. In some Scandinavian countries their house stock is newer and therefore have 3 phase as standard, giving them up to 22kW charging.
Oh, what a lovely SE/30 and IIci! The most beautiful classic Macintoshes ever.
Around here 120/208V three phase is available to smaller commercial buildings, apartments, and what not and is pretty common. 480V is mainly industrial and larger businesses that draw too much power to be serviced by a lower voltage. In other words 277V charging isn't going to be available at too many places unless they add another transformer to provide it.
One of the reasons 277V will take a bit longer is the safety factor. Heat specifically the incident energy is a squared variable. So that relatively small increase in voltage means there's a lot more heat in case of a fault. The equipment, wires, everything has to be able to safely handle the added stress.
Electrical engineer here who designs power systems for buildings. Nice video, but it does have one major issue. Most apartment buildings (even very large ones) and small to medium sized retail buildings do not have 480V delivered to them. The power comes in at 208V from the utility. I will have to look into whether this would make it economical to start bringing 480V in for apartment buildings with a lot of EV chargers. 277V will make fleet charging significantly more cost effective though, which I don't think you mentioned.
Thank you for sharing! -Travis
this was excellent. great work. agree, hope it can help expand lvl 2 which is sorely needed literally everywhere!
5:04 I assume you simplified this to make it easier to understand, but technically the 120 volts refers to the RMS voltage. The peak voltage as drawn on your graph would be √2 times higher, or 170 volts.
In terms of the power delivered, 120V RMS AC delivers the same power as 120V DC (for a given current), which is why we use the RMS voltage. However, because the peak voltage is actually higher, things like wire insulation and capacitors need to be designed for the higher peak voltage.
Yes. Our original video was nearly twice as long and went down too many rabbit holes, so we re-cut it and re-filmed parts to make things simpler and easier for the average EV intender to follow. RMS was just a bridge too far
I always wondered why commercial L2 chargers were at 208V but never bothered to google it. Thanks for answering that and also helping me understand why allowing 277V is a big deal! Can’t wait for everyone to switch to NACS.
Excellent video. As a European viewer I’ve just learned a lot about US power grid standards.
I appreciate the deep dive. Not that I understood it all, but I now understand just a little bit more about single- and triple-phase power -- and have a "high-level" understanding of how /why it changes things. Thanks. Keep 'em coming.
That was a fantastic deep dive, I’ve installed 240V charger at home and required a lot of other stuff and I thought I understood North American electrical circuits now.
But oh man commercial US power is very different, couldn’t take my eyes off your drawings. Good job mate!
Super informative and also interesting to see where manufacturers will go in terms of vehicle and charging equipment.
This was great. We are rewiring our building and parking for EV's and I wasnt aware of this difference!
Super clear and informative! Kudos!
Most excellent deep dive!!! Never even thought 277v would be option (or even consideration) for level 2 commercial! Nice...
Great job explaining that. I think most people will completely understand this.
Great explanation! Coming from Europe I now understand more about the system in America. Thanks a lot!
LOVED the detail. Getting into the weeds is my kink.
It's nice to watch a video on something you already understand to see if the author actually knows what he's talking about and as an electrician I can confirm, he got everything correct!
Thank you for this. Basically no one is talking about this.
Great, simple explanation of the voltage spreads and the benefits of operating "pre-transformer" on 3-phase power! Another reason to be excited about the move to NACS!
This was Technology Connections level explanation - well done!
Thanks!
You broke it down really well Alex. Great primer on why 277V is needed for the commercial side on EV charging.
Fantastic video. Very educational indeed. I would love to see more of these deep dives. As EE grad, I love this pivot to some nerd stuff.
I had wondered about why 240V & 208V were explicitly called out on my EVSE. But never bothered to think more about it. Now I know.
Thanks guys.
Thank you for the education. You are a standouts in your field. And I still have my SE/30 and NeXT Cube!
Wow, very interesting. I originally come from Australia and normally there a home will have single phase 240 V. However, if you install a Tesla wall connector, as you pointed out, you have to wire it three phase because of the phase load balancing requirements. The electrical system in the United States has always bamboozled me somewhat because I am so used to having a three phase environment for heavy electrical loads in a household. Great explanation Alex I learned a lot, particularly that the onboard chargers are current limited, not power limited and the difference between US Mains power delivery at a residential home as compared to a commercial property. I personally would very much like to see that in the near future on board EV chargers are all rated for at least 80 Amps, vs the current 40/48Amp, as with batteries the size of the Silverado they are not simply adequate enough to take advantage of super off peak rate time periods..
One easy way also to think of it is that a 480/3 vs a 208/3 has over double the power for the same amperage so you can cut you service size in at least half
This was great information! Great work!
I love this explanation! Please do more of these!
Really great overview on the potential of new standards. Great job, Alex!
Great explanation, really ticked all the curiosity boxes.
I love nerding out! 😇 Especially with a Mac SE/30 w/a Motorola 030 processor... that SE/30 was like a killer Mac IIci in a lil' box back then. 🤓 Oh wait there was a Mac IIci next to it!!! ha ha I LOVE it!!!
When will we start seeing NEMA 7-15, 7-20, 7-30, & 7-50 adapters for our Tesla mobile connectors? Thanks for your peak vs RMS disclaimer, as a power nerd I was vibrating watching your presentation. The adoption of 277 charging will make large level 2 sites much cheeper and more efficient. Thanks for getting this issue into the public eye.
Excellent episode, really found this very helpful!
This was awesome! Just as the detail started to make my eyes glass over, you brought it all home and made perfect sense to me. Great information!
Knowing more is usually better and it is in this case. Still don’t fully understand everything, but learned a lot in this video. TY
More deeper dives. I’ve definitely witnessed this Split1Phase 240 vs 3Phase 480 explanation before but it never stuck. In one ear and out the other leaving me confused.
You’ve got a clear, concise, effective teaching style that worked for me this time. Thank you so much.😊
Nice rundown..thanks
I had to rewind in a couple of spots cause I was like "wait, what?", but super interesting!
This was brilliant! Answered a lot of questions I had about single vs 3 phase power. Thank you!
Great information as always!
i loved this deep dive, Alex! I'm a bit of an electrical tech nerd too! used to work on emergency backup generators and transfer switches/paralleling gear.
That was excellent. I LOVE stuff like this.
1:47 excited to see working Macintosh
Thanks. Great info
Very well done. Thank you for the thorough explanation. 👍
As the owner of a BMW i4. Information like this makes it easier to understand charging speed differences. Thanks again.
Extremely informative and helpful 👍
This is really-really good and helpful! Thanks!
Brilliant, definitely not too deep. The big take-away is the ability to tap into a commerical 480V AC box, without needing any additional electrical transformers. I thought I was up to speed on the NACS connector and this video would rehash the stuff I already knew, but I was pleasantly surprised to be naive! Thank you
Great idea for a video and very well done! Homrun!
Well done Alex. Thanks again. Very informative.
Thanks for the lessons!
Loved the nerdiness. I dont understand electrical but stick a few sine waves on a graph and Im with ya. Thanks man!
That was a fantastic video. Thank you for sharing your knowledge.
Thank you for watching! -Travis
Excellent video Alex, thanks!
Great explanation!
Thanks for covering this Alex, Power Geek here.
I'd really love to see a deep dive into the toyota/lexus hybrid systems. the theory of operation if you will. how both mechanical and electrical power flow etc. I saw a deep dive into the honda systems a while ago and i enjoyed that a lot.
Excellent information! Thx!
Fantastic explanation Alex. Bravo.
For what I've heard, the j3400 standard for ac charging will make the eu style bring your own cable charging as an option.
It also specifies the same male mennekes connector for the evse side.
Since it has more pins you could put 277v on the L1 pin, neutral on the neutral pin and 120v split phase on L2 and L3 pins.
It would be a wiring nightmare, but you can support all vehicles needing 120v 240/208 and 277v.
I have heard there are a lot of cities code restrictions against using a single leg of three phase power. The Tesla Gen 2 wall adapter and the mobile connector already support 277 volts as well as all model 3s Ys and most model S/X cars. There is a great thread on 277 volt support at Tesla motor club forum. It seems code restrictions are likely to hold back deployment in the near term.
Good job explaining it!
Excellent video. Electricity is still a mystery but this made some sense out of it. I love the deep dive stuff.
That was fantastic. It explained a lot for me.
Thanks a lot for the deep dive, Jason....oh, wait
No, it wasn’t too deep, of course I was an electrician in the Navy, so it makes sense to me. Very informative, thank you.
What a great educational video, thanks!
It seems no one working on SAE J3400 talked to Canada, they use 600/347V for commercial 3-phase. Why not use the same voltage range as J3068?
Yea, in Canada you'll just have to make do with either a high-leg delta stepdown transformer that could give you 120/208/240V, but 347 I think was just too far outside the ~240V nominal window to logically support.
I learned something today thanks to you and you earned a subscriber. Awesome job thank you!
Thanks for watching and subscribing! -Travis
Model 3/Y and refreshed S/X can do up to 300VAC charging, even if it's not advertised. I would expect that the OBC's on most other EV's are capable of it too, but the software almost certainly doesn't support it considering the limit of J1772. But that does make me wonder if J1772 could be amended to support it. I can't imagine there's any physical limitation preventing it from handling a small increase in voltage.
Thanks for this info.
Thank you for the explanation of how to get how many Kw an hour you can charge at. I was curious how that worked and had wondered how you figured that number out and now I know.
Great content! Thank you!!
Great informative feature.
Wow this was a fantastic explanation! I've driven an EV for the past 8 years and know a lot of nitty-gritty details but this is new to me
Awesome explanation, Alex!
Thanks! 😃
Greately appreciated as the house I am buying has 3 phase, and Tesla is my next vehicle brand. I never knew exactly why 208 and 480 were or their relationship. Very interesting and informative as well as lucid.