New Wall Connector :)

[FlasherZ]

Explanation for dummies, please ?

The voltage in your home is based upon 240V between individual "hot" wires. You get 120V for your normal appliances by connecting to one hot wire and the grounded "neutral" wire.

In industrial areas or plants, including superchargers, it's based upon 480V to reduce the wire size needed for the same amount of power. The voltage between the grounded "neutral" wire and one of the hot wires in this case is 277V, which is still too high for the original HPWC. To create 240V or 120V, you have to use a second transformer, and that adds cost.

The ability to use these HPWC's at 277V allows for industrial locations to install them without having to buy a second step-down transformer at a higher cost. It means that Tesla could choose to install some HPWC's at each Supercharger location as well.

 

[SageBrush]

The ability to use these HPWC's at 277V allows for industrial locations to install them without having to buy a second step-down transformer at a higher cost. It means that Tesla could choose to install some HPWC's at each Supercharger location as well

Thanks for the explanation, and triple thanks for the tremendous charging FAQs.

 

[Cosmacelf]

Since these new HPWCs accept 277V, doesn't that imply that the cars, all of them, accept 277 AC volts as well? The HPWC isn't doing anything more complicated than passing the incoming voltage through a contactor (relay) and then onto the car, so it is the car's charger that has to accept and deal with 277 volts. Correct?

 

[pchilds]

Since these new HPWCs accept 277V, doesn't that imply that the cars, all of them, accept 277 AC volts as well? The HPWC isn't doing anything more complicated than passing the incoming voltage through a contactor (relay) and then onto the car, so it is the car's charger that has to accept and deal with 277 volts. Correct?

Yes, all model S', from day 1, accept 277 volts.

 

[FlasherZ]

Since these new HPWCs accept 277V, doesn't that imply that the cars, all of them, accept 277 AC volts as well? The HPWC isn't doing anything more complicated than passing the incoming voltage through a contactor (relay) and then onto the car, so it is the car's charger that has to accept and deal with 277 volts. Correct?

Yes. The car chargers could always deal with 277V (because that's used in the superchargers), even if the firmware may have limited the current. The issue was the HPWC's, which couldn't handle the higher voltage.

 

[arg]

anyone know whether the UK version of this can also charge other type 2 (7pin mennekes) EV's ??

The installation manual for the EU version strongly implies that it supports non-Tesla vehicles, as there are various error codes where it says "if Tesla vehicle, contact Tesla; if non-Tesla vehicle contact the original manufacturer".

Also in the same manual there's an outline schematic which shows that there is current monitoring via current transformers, such that the 'sharing' feature can work without needing any Tesla-proprietary signalling between the chargepoint and car.

However, it doesn't actually make a clear statement of compatibility. Perhaps we will see that when marketing materials appear.

The US version however seems to be going the other way - with the new 277V support, that renders a Tesla connector to J1772 connector adapter unsafe - as the Tesla connector (always proprietary) now has a de-facto specification that it's a source of up to 277V rather than the 208-240V specified by J1772.

 

[scaesare]

The installation manual for the EU version strongly implies that it supports non-Tesla vehicles, as there are various error codes where it says "if Tesla vehicle, contact Tesla; if non-Tesla vehicle contact the original manufacturer".

Also in the same manual there's an outline schematic which shows that there is current monitoring via current transformers, such that the 'sharing' feature can work without needing any Tesla-proprietary signalling between the chargepoint and car.

However, it doesn't actually make a clear statement of compatibility. Perhaps we will see that when marketing materials appear.

The US version however seems to be going the other way - with the new 277V support, that renders a Tesla connector to J1772 connector adapter unsafe - as the Tesla connector (always proprietary) now has a de-facto specification that it's a source of up to 277V rather than the 208-240V specified by J1772.

I wonder if the new HPWC would be smart enough when operating at 277V to only close the contactors and supply power to a vehicle when the vehicle requests such via digital signalling?

In other words, if all the HPWC receives from the vehicle is a standard J1772 square-wave/duty-cycle on the pilot pin, assume it's a vehicle that is not capable of 277V, and not supply power.

 

[Cosmacelf]

Yes. The car chargers could always deal with 277V (because that's used in the superchargers), even if the firmware may have limited the current. The issue was the HPWC's, which couldn't handle the higher voltage.

Good to know. Hmm, I wonder if the UMC can handle 277V. I know it isn't rated for it, but I have been asked in the past about making an adapter to plug into a 277V receptacle (yes they exist).

 

[UKM3]

thanks guys, the reason for the question is that I'd like to replace my existing Rolec EV chargepoint with a Tesla Wall Connector to match my forthcoming Tesla. I would still like to be able to charge the i3 from that connector too, if possible.

 

[FlasherZ]

Good to know. Hmm, I wonder if the UMC can handle 277V. I know it isn't rated for it, but I have been asked in the past about making an adapter to plug into a 277V receptacle (yes they exist).

If I recall correctly, @Ingineer and Tony Williams have both said that the UMC and original HPWC cannot safely be run at 277V because of the rating of some components (I believe optocouplers, etc., played a key role in that determination, but I'm unsure).

 

[brianman]

Yes. The car chargers could always deal with 277V (because that's used in the superchargers), even if the firmware may have limited the current. The issue was the HPWC's, which couldn't handle the higher voltage.

Point of clarification. I think you're saying "because the cars and the superchargers use the same chargers under the covers" we can infer that the car's chargers can handle 277V because the supercharger's chargers can.

Aren't you assuming some things about the firmware / software decision and manufacturing specifications of the superchargers chargers and the car's chargers?

Further I think even if it did hold true for 40A single / 80A "dual" chargers of original Model S, it most certainly doesn't necessarily hold true for post-facelift 48A / 72A flavors of Model S.

Or am I missing something?

 

[FlasherZ]

Aren't you assuming some things about the firmware / software decision and manufacturing specifications of the superchargers chargers and the car's chargers?

Well, I carefully chose my words. "Could always deal with" is different than "taking advantage of". "Could always deal with" refers to the ability of the hardware to withstand higher voltage inputs to the switching power supply. We know that there are no additional critical electronics between the charging port and the charger (the HVJB doesn't count), and we know the same chargers are used in the supercharger cabinets which use 277V in normal operation.

It didn't mean that the higher voltage will result in any additional power, although we have anecdotal evidence - from some of the crazy frankenEVSEs that have a boost transformer spliced into the coupler cable - that the car can indeed do it.

Further I think even if it did hold true for 40A single / 80A "dual" chargers of original Model S, it most certainly doesn't necessarily hold true for post-facelift 48A / 72A flavors of Model S.

Once again, I'd choose my words carefully. It seems the chargers "can deal with" 277V. But the firmware in the Model X right now demonstrates that the car will not take advantage of it, as it is limited to 17.5 kW and will restrict current as voltage goes up.

 

[nwdiver]

Point of clarification. I think you're saying "because the cars and the superchargers use the same chargers under the covers" we can infer that the car's chargers can handle 277V because the supercharger's chargers can.

Obviously a question for Tesla if you're concerned but I don't see Tesla selling HPWCs that are physically identical but don't work with older cars...

And as Flasher pointed out... the hardware is compatible with 277v.

This is HUGE for commercial installs... 240v isn't very common when there's 3 phase service so this is an upgrade from 208 => 277... ~33% more power AND it should be cheaper to install too

80A @ 277v is ~22kW A row of these at superchargers could take a bit of stress off the busier locations especially if someone just needs ~30 miles to make it home...

Does anyone know if other EVs can also use 277 or is Tesla the only one...

 

[FlasherZ]

This is HUGE for commercial installs... 240v isn't very common when there's 3 phase service so this is an upgrade from 208 => 277... ~33% more power AND it should be cheaper to install too

It depends... If you have 480VAC service, then you have to use a distribution transformer for standard 120V stuff anyway. You can choose whichever voltage you want. I've probably seen more split-phase 240V/120V at 480VAC sites than I have seen 208Y/120V. The biggest benefit here is that you won't have to buy distribution step-down transformers to handle these heavy charging loads, you can use your primary facilities instead.

 

[nwdiver]

You can choose whichever voltage you want. I've probably seen more split-phase 240V/120V at 480VAC sites than I have seen 208Y/120V.

Hmmm... guess we have different experiences... I've never been to a hotel with 240... I have an adapter for the room AC; they're always 208. My workplace is ~90% 208... but we do have a few 240v split-phase lines... sadly not to our Chargepoint stations Those are ~208 and once you start pulling ~20A they drop to 200v... they ran #8 line >100'...

The other advantage is 277v would only need a single pole breaker since it's L-N but 208 requires a double pole breaker being L-L. So you should be able to squeeze twice as many circuits on the same panel.

Is commercial service like hotels and restaurants usually 480v that gets stepped down to 208v or do they get fed 208v? 480v may only be common at larger facilities...

 

[FlasherZ]

Is commercial service like hotels and restaurants usually 480v that gets stepped down to 208v or do they get fed 208v? 480v may only be common at larger facilities...

480VAC is typically only found in larger/industrial locations. Most places that use only 208Y/120V have a transformer bank that steps down primary (7.2 kV or 14.4 kV) down to 208Y/120V directly.

 

[SageBrush]

480VAC is typically only found in larger/industrial locations. Most places that use only 208Y/120V have a transformer bank that steps down primary (7.2 kV or 14.4 kV) down to 208Y/120V directly.

Do you know if this is also true in countries that use 240v throughout the home ?

 

[miimura]

Do you know if this is also true in countries that use 240v throughout the home ?

In Europe, for example, any facility that needed more than about 15kW-25kW would get 3 phase service 400Y/230V. You would have to go much bigger to get a primary voltage higher than that in those areas.

 

[SageBrush]

In Europe, for example, any facility that needed more than about 15kW-25kW would get 3 phase service 400Y/230V. You would have to go much bigger to get a primary voltage higher than that in those areas.

Thanks, but I probably was not clear in my question.

I was wondering if it made sense for other grids to transform HV down to 480V, and then split into 240v for each home. I am sure it is obvious by now -- I know just over zilch when it comes to electricity, so the question may be idiotic.

 

[nwdiver]

Thanks, but I probably was not clear in my question.

I was wondering if it made sense for other grids to transform HV down to 480V, and then split into 240v for each home. I am sure it is obvious by now -- I know just over zilch when it comes to electricity, so the question may be idiotic.

The voltage that your 240v comes from is likely ~14.4kv not 480v.