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[Crissa]

Don, you're just talking gibberish.

The station's signal tells the vehicle what amperage it can charge at.

Again, that's important.  Ask anyone why.

-Crissa

[GoneToPlaid]

A whole lot of engineers spent years arguing over the SAE J1772 standard - I'll leave it to them, thanks.

I have two Chargepoint cards, for two different accounts, on the way.  Soon see if that reduces friction when dual-J charging.

[DonTom]

Don, you're just talking gibberish.

The station's signal tells the vehicle what amperage it can charge at.

Again, that's important.  Ask anyone why.

-Crissa

I will ask you why.

How does it do that on a J-1772?  Does it change the AC voltage or what? 

And more importantly, why is it NOT necessary to tell a 14-50R the same? It just charges. If you have a 3KW charger, it will charge up to  3KW. If you have a 12 KW charger, it will charge up to  12 KW.

So why does one need to be told and not the other?

-Don-  Reno, NV

[DonTom]

A whole lot of engineers spent years arguing over the SAE J1772 standard

I certainly can understand why!

I just find it kinda stupid to only have 6.6 KW available when there is at least 12 KW available to start with.

My real complaint is I want to be able to always charge my bike at 8KW from a single outlet, when on the road,  just as I do at home!

-Don-  Reno, NV

[Crissa]

I will ask you why.

How does it do that on a J-1772?  Does it change the AC voltage or what?

No, it doesn't change the AC.  The pilot signal tells the vehicle what's available.
https://en.wikipedia.org/wiki/SAE_J1772#Proximity_Pilot

The vehicle measures the pilot signal for resistance - just a like a multimeter - and gets a result that tells it what power the station is capable of.

And more importantly, why is it NOT necessary to tell a 14-50R the same?

Because a 14-50 only does 50a.  It is considered unsafe or broken if it cannot supply 50a.  It only is allowed to be installed where 50a is available.

There's literally a different shape plug for every amp supply.  15, 20, 30, 50.  You can't plug a 20 into a 15.  You can't plug a 30 into a 20.  You can't plug a 50 into a 30.

But you can always plug a J1772 into a J1772 no matter if it's a 13a or a 32a because the standard requires the EVSE to tell the vehicle what's available, and the vehicle to adapt to what's available.

-Crissa

[DonTom]

Because a 14-50 only does 50a.

Only?  What vehicle has an AC charger of more than 12,000 watts (240VAC times 50 amps=12,000 watts)? But perhaps there is a Tesla 14 KW out there as 14KW destination charge stations do exist.

That is what makes J-1772 so stupid, IMO. Unnecessary limitations, IMO. Most of them are probably fed using a 50 amp (or more) source.

Yeah, they need the pilot because of the limitations of it that would NOT be there if the J-1772 didn't exist at all and we could simply get to what is feeding it.

IOW, tell the J-1772 that your 12 KW vehicle AC charger  can only accept  6.6 KW because the J-1772  is only capable of 6.6 KW. But if the J-1772 didn't  exist you could then get the full 12KW. That's what makes J1772 so stupid, IMO.

Notice Tesla Destination did NOT go that stupid route and they have  14KW AC stations all over. The nice thing is that even our Zeros can use them with an adapter. None of that needing two charge stations BS. Doesn't  matter what Telsa or non-Tesla is using it, get up to 14KW, at least with some. And that is fine even with your bike. It will only draw what your bikes AC charger  is capable of. No need to tell a 14-50R (or whatever)  anything.

BTW, I am not sure if any Teslas have a 14KW AC charger. I have not yet heard of such, but I do wonder why some of the Tesla Destination stations  are 14KW of AC capable.


-Don-  Reno, NV

[Biff]

Because a 14-50 only does 50a.

Only?  What vehicle has an AC charger of more than 12,000 watts (240VAC times 50 amps=12,000 watts)? But perhaps there is a Tesla 14 KW out there as 14KW destination charge stations do exist.

That is what makes J-1772 so stupid, IMO. Unnecessary limitations, IMO. Most of them are probably fed using a 50 amp (or more) source.

Yeah, they need the pilot because of the limitations of it that would NOT be there if the J-1772 didn't exist at all and we could simply get to what is feeding it.

IOW, tell the J-1772 that your 12 KW vehicle AC charger  can only accept  6.6 KW because the J-1772  is only capable of 6.6 KW. But if the J-1772 didn't  exist you could then get the full 12KW. That's what makes J1772 so stupid, IMO.

Notice Tesla Destination did NOT go that stupid route and they have  14KW AC stations all over. The nice thing is that even our Zeros can use them with an adapter. None of that needing two charge stations BS. Doesn't  matter what Telsa or non-Tesla is using it, get up to 14KW, at least with some. And that is fine even with your bike. It will only draw what your bikes AC charger  is capable of. No need to tell a 14-50R (or whatever)  anything.

BTW, I am not sure if any Teslas have a 14KW AC charger. I have not yet heard of such, but I do wonder why some of the Tesla Destination stations  are 14KW of AC capable.


-Don-  Reno, NV

Don, I agree that replacing  J1772 stations with NEMA 14-50 plugs would be good for some people.  The problem is that like Carissa indicated using J1772 makes things more compatible.  A lot of the J1772 stations aren't capable of 50A, I would say most of them aren't, so that basically ends the conversation about replacing J1772 stations with 14-50 plugs.   Requiring that every charging station has 50A capability, and access to reset the breaker if it trips, is cost prohibitive. A lot of places have shared stations, so if only one charger is being used, you get 32A,  if the other station nearby starts getting used, your current will drop to 16A, and the other station will use 16A too.  You can't do that without some sort of communication, and for better or worse, the industry has determined that J1772 is the standard. 

-ryan

[DonTom]

Don, I agree that replacing  J1772 stations with NEMA 14-50 plugs would be good for some people.  The problem is that like Carissa indicated using J1772 makes things more compatible.  A lot of the J1772 stations aren't capable of 50A, I would say most of them aren't, so that basically ends the conversation about replacing J1772 stations with 14-50 plugs.   Requiring that every charging station has 50A capability, and access to reset the breaker if it trips, is cost prohibitive. A lot of places have shared stations, so if only one charger is being used, you get 32A,  if the other station nearby starts getting used, your current will drop to 16A, and the other station will use 16A too.  You can't do that without some sort of communication, and for better or worse, the industry has determined that J1772 is the standard. 

-ryan

I think you will find that most J plugs are fed by circuits that can do a lot better than 50 amps. BTW, today, I charged at an 80 amp (yeah 80 amp) Tesla destination station. 240 VAC times 80 amps=19,200 watts. I would NOT be surprised to find that type of capacity going into J-plugs. It's the J-plug itself that is not rated for such current. That is what  makes it so dumb these days. So much current capability going in, but so little available after it gets to most J-1772 boxes.  But it's an old standard.

FWIW, I cannot think of any EV that cannot charge from a 14-50R in one way or another. But some granny cables are not rated that high. Tesla limits anything other than their own connectors to 38 amps (7,680 watts). But at least the 14-50R  isn't limited by the  38 amps as are most J-plugs (there are a few J-plugs that can do 8.5 KW these days, but not many).

I am in the habit of looking at the capacity of every AC charge station I use. That's how I discovered the 80 Amp ones at USA ParkWay (near the Tesla battery plant). BTW, these boxes also said "for indoor use only" yet they were all outside. So I do not know for sure that they are wired for 80 amps. Plugshare says they are 16KW, which will be only 66.6 amps, but they clearly say 240 VAC and 80 amps right on the Tesla box.

-Don-  Reno, NV

[Crissa]

Don, a 14-50 literally requires a 50a circuit.

A J1772 does not.

A plug that goes into a 14-50 only goes into a 14-50.  It can't plug into anything else.  And further, every 14-50 can only be put on a 50a circuit.  Only.

A J1772 can be fitted to a 15a, a 30a, or a 50a circuit.  One plug to rule them all, instead of four.  And the vehicle can change what charger capacity based upon what's available, instead of you flipping switches and guessing until the breaker pops.

You might be 'surprised' that 80a wasn't available.  But you know what?  Do you have 80a 'available' from your dryer outlet?  From your regular wall outlet?  From a 30a RV outlet?  No?  But you could put a J1772 EVSE on any of those.

-Crissa

[DonTom]

Don, a 14-50 literally requires a 50a circuit.

What makes you think that? You can use 14-50R with any current  from 0 to 50 amps.

A plug that goes into a 14-50 only goes into a 14-50.

Ever hear of adapters? You can plug a J1772 into a 14-50R. I have a stock granny cable that can only be used with 14-50R, but it's limited to 15 amps (3.6 KW) even if plugged into the full 50 amps (12,000 watts) which again makes my point.

-Don-  Reno, NV

[Crissa]

Don, a 14-50 literally requires a 50a circuit.

What makes you think that? You can use 14-50R with any current  from 0 to 50 amps.

True, but meaningless.

I thought you said you knew the difference between load and circuit?  The supply circuit for a 14-50 must be capable of 50a.  You cannot legally install them on just any circuit.

Ever hear of adapters?

Have you heard that a J1772 EVSE automatically tells the vehicle the supply availability, hence is itself an adapter?

-Crissa

[DonTom]

I thought you said you knew the difference between load and circuit?  The supply circuit for a 14-50 must be capable of 50a.  You cannot legally install them on just any circuit.

Is that code somewhere? I don't see why anybody would care if you have a 14-50R used with a 5 amp circuit breaker with ten amp wiring.

-Don-  Reno, NV

[Crissa]

I thought you said you knew the difference between load and circuit?  The supply circuit for a 14-50 must be capable of 50a.  You cannot legally install them on just any circuit.

Is that code somewhere? I don't see why anybody would care if you have a 14-50R used with a 5 amp circuit breaker with ten amp wiring.

Yes.  It would be against the uniform electrical code.  It would defeat the safety purpose of 50a plugs being impossible to plug into 5a circuits.

-Crissa

[DonTom]

Yes.  It would be against the uniform electrical code.  It would defeat the safety purpose of 50a plugs being impossible to plug into 5a circuits.

-Crissa

I don't see much of a safety issue if it's on a 5 amp breaker. Equipment that draws more just won't work when the CB trips. But I don't try to keep up with why they have some building codes. They often change from one town to the next.

-Don-  Reno, NV

[Crissa]

I don't see much of a safety issue if it's on a 5 amp breaker. Equipment that draws more just won't work when the CB trips.

• That would be illegal.
• That would be a big liability.
• That would be a pain for the user.

• "What do you mean, I can only charge at 5a!  I plugged in a 50s plug!"
• "What do you mean it tripped?  How do I turn it back on?"
• "I have to plug it in, read the amperage on the label, then select that amperage n my vehicle?"
• "Oh no, the breaker fused/tripped late the wires are on fire!"

*sigh*

-Crissa