NACS has 277 Volt A/C capability, how will current EV's handle that?

It would be interesting to see the source of your information as I wouldn't expect to see destination chargers using 277 volts in North America.

It's this a European installation?


https://www.tesla.com/support/commercial

 

CCS1 is DC voltage and generally runs around 400 to 500 volts dc, though a number of cars are being produced with upwards of 800-900 volts such as Lucid Porsche, Hyundai and KIA. NACS can be used for ac or dc charging on a Tesla, or DC on a CCS1 plug with a magic dock adapter.

The Tesla destination charger is an ac EVSE. It can run on single phase ac from 240 volts typical found in a house or 277 volts single phase off a 480 volt three phase found in industrial settings.

I think the thing SAE and CharIN are trying to standardize is the communication protocol to establish what the DC charge rate for a particular car will be. Each car has a unique charging curve that the charger need to match so as not to damage the battery

 

OK, got it. One can connect the device to 277 volts. However, Tesla doesn't recommend 277 volts as it may cause charging issues.

 

Most of the EVSE already have an over voltage fault mode for ac charging. My 8 year old GE Durostation faults at 270 volts. Above that it simply stops charging. AC adapters have been available for j1772 to destination charges for a number of years. I have had one for four years now and used it a number of times at destination chargers with my Kona. These are NACS to J1772 which is different than NACS to CCS1 which is DC fast charging. If you have a J1772/ CSS1 car you will need two adapters one for ac and one for dc. AC adapters are available now. DC adapters will be available for use at Tesla superchargers next year for those companies that have reached an agreement with Tesla.

 

Munro has often commented that Tesla builds more than the published limit in their cars. Although I don't have a handy reference, both Munro and Ingineer have YouTubes that addressed whether Tesla's had a bi-directional AC capability.

They revealed Tesla uses diodes, one way only, to initially convert AC-in to DC. The rest is the glue logic needed to handle P-factor, noise, and current limits.

Personally, I am curious what 'value added engineering' the SAE might contribute to NACS. There may be a definition of optional Vehicle-to-Grid interface but that would not be mandatory. There are good engineering reasons for not tapping vehicle batteries for grid power. Solar storage batteries, yes, but vehicle batteries have hard requirements:

• high energy density - especially for light weight
• accident safety
• long life - so the car doesn't become a boat anchor

Bob Wilson

 

Practically anything that converts AC to DC uses diodes.

_H*

 

Some of the ones claiming vehicle-to-grid out the CCS-1 connector used MOSFETs. Not a practice I have any interest in.

I approve of NEMA style connectors if pulling AC from the battery.

Bob Wilson

 

You say that but Tesla has a whole section on installing the Wall Connector on 277V. https://www.tesla.com/sites/default/files/pdfs/wall-connector-eu/tesla-80a-wall-connector-installation-manua-en-v1.pdf