I was wondering with all the talk of NACS, what would happen to J1772. I think I found the answer, unless folks here see it differently. Thanks!
What is the currently maximum available performance of NACS?
CCS is designed up to 1000V and 500A. Charging stations offer typically up to 350 kW.
What do the available NACS charging stations offer? As I remember Tesla is only using 400V batteries, so with 500A they only get up to 200kW.
So the switch to NACS sounds like a performance downgrade. But yes: probably a usability upgrade but at the cost of longer charging times.
Is Tesla planning to switch to 800V too? So they can deliver more performance?
Looks like there is a 1000V variant. I’m guessing there just aren’t any chargers built with it yet.
North American Charging Standard Technical Specification 6. Ratings 6.1 Voltage Rating The North American Charging Standard exists in both a 500V rated configuration and a 1,000V rated configuration. The 1,000V version is mechanically backwards compatible (i.e. 500V inlets can mate with 1,000V connectors and 500V connectors can mate with 1,000V inlets)
NACS standard specification Tesla published actually included modifications to the Tesla plug to allow for higher voltages. The current Tesla connectors on all the superchargers can’t do 800V safely.
Edit: correction from below.
Specification. Tesla published a specification. It can’t publish a standard, since it isn’t a standards body. J3400 will be the standard based on the specification published by Tesla after checking and possible refinements. Nitpicky, yes, but also not. Since standardization includes stuff like governance agreements, governance organization, Patent and IP licensing clearance and so on. The technical spec is only part and maybe simplest part of the standard. The really important part is the legal and contractual matter, so that when standards body does officially adopt standard everyone can use it with confidence of knowing under what terms and payment said standard is offered and that there will be no lawsuits waiting to jump out in the bushes.
Also theoretically there can be technical differences between J3400 and Tesla connector, if those changes are done in backwards compatible fashion to Tesla’s earlier plug. Not out of having to, but out of it being desired feature for utilization of existing infrastructure.
Whole point of J3400 is it isn’t the “Tesla plug” anymore, it is a plug governed by Society of Automotive Engineers. It just happened to originate from specification developed by Tesla originally.
Just like how the European Type 2 plug is sometimes called Mennekes, since Mennekes Elektrotechnik GmbH & Co. KG was the original designer. However officially and governance wise it is now the Type 2. It is governed by IEC, not by Mennekes anymore.
Specification. Tesla published a specification. It can’t publish a standard, since it isn’t a standards body.
Corrected
Whole point of J3400 is it isn’t the “Tesla plug” anymore, it is a plug governed by Society of Automotive Engineers. It just happened to originate from specification developed by Tesla originally.
That’s why I specifically called out the Tesla plug on their vehicles and superchargers vs the NACS plug.
IIRC, Tesla claims their connector is rated for 1kV as well, and at a slightly higher total power rating than NACS. They haven’t actually fielded chargers above 400V, though. It seems though that the general consensus is that the NACS connector is actually more or equally capable overall compared to the CCS (J1772) connector, in a smaller form-factor. At first I thought it was a pretty odd switch, but now that it’s an open standard managed by SAE and the specs seem to be at worst comparable… it’s not exactly a bad idea for the OEMs to use it.
Actually, it’s not just another plug. The fact that the same Pins are used for AC and DC charging adds a little bit more complexity to the car. Either you need additional switches in the car to separate the Onboard AC-Charger from the charging port, or the AC-Charger must be designed to withstand an DC input on its AC-Input contacts. That probably won’t be the biggest problem when the DC-voltage is just around 400V, as the AC-voltage is not that far away.
But if you switch to 800V Batteries (which most of the industry is doing), that probably could get more challenging, as the AC-charging-voltage won’t change.
We‘ll see what the car industries solution will be.
