-
Want to remove ads? Register an account and login to see fewer ads, and become a Supporting Member to remove almost all ads.
Info from Tesla - 277v feed to Wall Connector (HPWC) - Which Cars Support It
- Thread starter eprosenx
- Start date
The Gen 3 Wall Connector manual makes no mention of 277 volts, but it specifically mentions 200 - 240 volts nominal. Elsewhere, it mentions connecting the unit line-to-line instead of line-to-neutral. It's seems to me that the Gen 3 unit only supports split-phase line-to-line connections, aka no 120 volt and no 277 volt connections.
The question above is about the Model Y and its support for 277 volt charging via a Gen 2 Wall Connector. Since the Y is similar to a Model 3, I suspect it does support it. I'm also curious about the new Model S and soon-to-be new Model X. Unfortunately, there are very few Gen 2 units hooked up to 277 volts out in the wild, so it will probably take a very long time before we find out.
Last edited:
Darkfox021
Member
Thank you.
Although we know Gen 2 supports it, I'm not specifically seeing any reference to 277V in the Gen 2 manual. Does it recommend line-to-neutral (i.e. is there a change that rules out Gen3 support for 277v)? I think pages 7-9 are relevant, but interpreting is above my pay-grade.
Tesla removed mention of 277v from the Gen 2 manual at some point due to problems with S & X sensitivity to high voltage (mentioned earlier in this thread).
Gen 2 definitely supports line-to-neutral since it can be hooked up to 120 volt circuits (single phase with neutral). 277 is also single phase with neutral, as line-to-line would produce 480 volts.
EfficientWatts
Member
Gen 3 definitely still supports L-N connections, though I think there's no explicit dip switches required anymore. If you look at the manual, they refer to the 2nd line as L2/N (look at the wiring diagrams), which tells me they support L-L (split phase) and L-N; South Korea would be an example of where this HPWC would be used as well since they're 240V.
When talking about voltage ranges, they say nominal 200-240V, and nothing about L-L or L-N voltages.
Unfortunately, I get the feeling gen 3 HPWC does not support 277V. In the troubleshooting section, they talk about over/undervolt error codes, and they say to check to make sure it is in the nominal 200-240V range; not sure what the tolerance is is but I don't think it would go all the way up to 277V (unless the voltage sagged a lot). Of course someone could try just to see, but even if it could support it Tesla could firmware lock it out.
ASH*TAR
Member
Just checking back to see if anyone tried this yet?
I'm wanting to do it too. I already ordered a buck transformer but it hasn't shipped yet. This seems more ideal and effecient.
I'm wanting to do it too. I already ordered a buck transformer but it hasn't shipped yet. This seems more ideal and effecient.
ASH*TAR
Member
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.
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 think you mean a DC-DC converter in parallel with the inverter. Technically, you could direct feed a solar string into the car assuming the pack was warm, low SOC, string voltage was high enough and string short circuit current was reasonable. It's not going to operate at the peak power point, but wouldn't have conversion losses. Just need the handshaking with the car and isolation contactors (along with other safety circuits).
Seems like something Tesla might add to a future version of Powerwall.
That’s a great setup. 12.8 kW instead of 11.5 kW. 11% faster charging. I would have been really happy about this when I drove from Grand Rapids, MI to Washington, D.C. exclusively on Tesla wall connectors.
I don't think you would get that. The onboard chargers (at least the last several generations of them) are limited on BOTH amps and kilowatts and will cap and reduce if either is going to be exceeded. If you're running at a lower level of amps, like 32 or 40 that is well below the max power limit, then yes, you can boost the power by this voltage increase. But I've seen plenty of examples in the forums where if people are trying to run at the max amps already, like 48A here, and you boost the voltage like this, it won't keep the current that high. It backs off the amps to 47, 46, 45, etc. to stay under that 11.5 kW max power limit.
So at 277V, it will reduce the amps to about 41 or 40 to keep from going over that 11.5 kW. This voltage boosting only helps if you have to be running at a lower number of amps for some other reason, like the wiring of the circuit or cable thickness. Then, you could get a bit more power that's still within the limit of the onboard charger.
His screenshot shows 47 amps at 273 volts. That’s 12,831 Watts.
Oh, I hadn't seen that. That is much higher than the older chargers used to do. They used to enforce their rated power limit pretty hard.
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.
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.
P.s. I used a NEMA 6-20 receiver pigtail outlet. I manually wired the pigtail using a 12 gauge 12/2 (with 3rd wire ground) wire —both bought from Home Depot. Need to buy wire stripper to do this. I thought about using a NEMA 5-20 receiver outlet but I felt with 277 volts, that a 6-20 receiver is safer. And it’s more the wire gauge that is more important.
I used a website to calculate the wire gauge needed for a 277 volt 16 amp line - 12 gauge wire is consistently the result across multiple wire calculation websites.
Online Wire Size Calculators & Tables
This wire size calculator will calculate the appropriate wire gauge for a circuit based on amps, voltage, distance, and load. This website provides a wire size calculator, voltage drop calculator, wire ampacity charts and more.
wiresizecalculator.net
Very cool. I wish more L2 infrastructure was wired with 277V.
It's normal to see voltage drop under load. It's expected.
SageBrush
REJECT Fascism
I'm not following.
Are you using one phase at 277v ?
---
If true, I wonder what is possible, either now or in the future. Perhaps ... as high as 48 Amps * 0.48 kW = 23.04 kW !??
That would do wonders in competing with expensive 25 kW DC charging
Last edited:
Yes, this must be 277Y480V service with the neutral and one leg wired to an outlet. At 240V, 48A would be 11.5kW. This would be 13.3kW at full current and voltage. However, the on-board charger may also have a power limit. The original Model S OBC was 40A and would limit to 10kW (250V * 40A) regardless if you fed it with a higher voltage than 250V. I would not be surprised if 3/Y chargers would limit to 12kW (250*48) at voltages over 250V.
The onboard charger's limit is about 12.5 - 13 kW, at which point it will start reducing amps.
SageBrush
REJECT Fascism
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 ?
