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[Curt]

So I do wonder why there is only 7 KW available from J1772 stations. Anybody know why they usually cannot handle the full 12 KW?  What is so different in a Tesla Wall Connector where 12 KW is the norm? And since almost every 14-50 is wired for 50 amps (and a lot more is possible), what is the issue that prevents most J1772 stations from doing 12KW?

The limit for J1772 is 80 A @ 240 VAC (19.2 kW).

However, the industry seems to have settled on 32 A as a de facto, practical limit. All of the most popular EV cars on the market have a 32 A maximum.

No more than 40 A should be drawn from a 14-50 plug, in accordance with the rule that continuous draw should not exceed 80% of rated capacity.

[Curt]

Zero has taken the approach of having the highest AC charging available on any EM since there are far more AC chargers than CCS chargers in the country now.  As that stat changes I'm sure Zero will move in that direction but it will require a full battery redesign as the minimum voltage has to be over 250V (I think, maybe just 200V) and that is a major move.

I wonder why they couldn't divide the battery into three sections, and then use six smaller contactors to change them to a series configuration during charging and a parallel configuration during operation?

[princec]

Well, they probably could, they just ... haven't.

Cas

[DonTom]

The limit for J1772 is 80 A @ 240 VAC (19.2 kW).

However, the industry seems to have settled on 32 A as a de facto, practical limit. All of the most popular EV cars on the market have a 32 A maximum.

No more than 40 A should be drawn from a 14-50 plug, in accordance with the rule that continuous draw should not exceed 80% of rated capacity.

Yeah, I know the 80% rule, but I figure 99% is okay if you're keeping an eye on it  and not trying to leave it at that for days at a time.

I have seen some J1772 stations say they have a 5.5 KW limit. Says so right on the screen of this one at the Fox Peak Station. And here is one that says 6.6 KW limit right there.

So where have you seen 19.2 KW J1772? Are you in Europe where things are different than here in the USA?

-Don-  Reno, NV

[NEW2elec]

Zero has taken the approach of having the highest AC charging available on any EM since there are far more AC chargers than CCS chargers in the country now.  As that stat changes I'm sure Zero will move in that direction but it will require a full battery redesign as the minimum voltage has to be over 250V (I think, maybe just 200V) and that is a major move.

I wonder why they couldn't divide the battery into three sections, and then use six smaller contactors to change them to a series configuration during charging and a parallel configuration during operation?

Yes!  Although the (old) monolith was four 116V "bricks" so if they could be switchable to series giving it 464V and back to parallel for riding.
I had talked about that years ago and got crickets from the EEs so maybe some other reason to not do it but it seems like a good idea to me.

[Crissa]

I wonder why they couldn't divide the battery...

...Because that takes a bunch of relays which can fail and someone else patented this process so no one else can do it for another fifteen years or so.

-Crissa

[Curt]

Yeah, I know the 80% rule, but I figure 99% is okay if you're keeping an eye on it  and not trying to leave it at that for days at a time.

I have seen some J1772 stations say they have a 5.5 KW limit. Says so right on the screen of this one at the Fox Peak Station. And here is one that says 6.6 KW limit right there.

So where have you seen 19.2 KW J1772? Are you in Europe where things are different than here in the USA?-Don-  Reno, NV

L2 charging is definitely in the category where the 80% rule applies. You can't keep an eye on wires and wire nuts inside the wall.

I didn't say or imply all J1772 stations are 32 A.

I've never seen a 19.2 KW J1772, but that is the spec maximum, not "The issue is the J1772 plug itself. Only approved for 6.6 KW."

I'm in the SF Bay Area.

[DonTom]

L2 charging is definitely in the category where the 80% rule applies. You can't keep an eye on wires and wire nuts inside the wall.

I didn't say or imply all J1772 stations are 32 A.

I've never seen a 19.2 KW J1772, but that is the spec maximum, not "The issue is the J1772 plug itself. Only approved for 6.6 KW."

I'm in the SF Bay Area.

I was going by this from Wikipedia:

"Avcon manufactured a rectangular connector compliant with specification SAE J1772 REV NOV 2001, capable of delivering up to 6.6 kW of electrical power."

Perhaps the problem is that most of our J1772 stations are old, but even many of the new ones have a limit of  less.

While J1772 (and everything else hard wired) will follow the 80% rule, how do you know what circuit the J-station is on? Even at this house, I could have had mine wired in for more than the 12 KW as my panel had more than that available.  Just use thicker wire and a 100 amp breaker and then I would be good for a continuous 80 amps or 19 KW. But all I need is the 12 kW (48 amps) to charge my Tesla. It's a 12 KW AC charger. I also charge all my electric motorcycles with this and a TeslaTap.

I am from the SF west bay area. Mainly San Mateo.

-Don-  Reno, NV

[Curt]

I was going by this from Wikipedia:

"Avcon manufactured a rectangular connector compliant with specification SAE J1772 REV NOV 2001, capable of delivering up to 6.6 kW of electrical power."

Perhaps the problem is that most of our J1772 stations are old, but even many of the new ones have a limit of  less.

While J1772 (and everything else hard wired) will follow the 80% rule, how do you know what circuit the J-station is on? Even at this house, I could have had mine wired in for more than the 12 KW as my panel had more than that available.  Just use thicker wire and a 100 amp breaker and then I would be good for a continuous 80 amps or 19 KW. But all I need is the 12 kW (48 amps) to charge my Tesla. It's a 12 KW AC charger. I also charge all my electric motorcycles with this and a TeslaTap.

I am from the SF west bay area. Mainly San Mateo.

The 6.6 kW connector you mentioned is from 19 years ago. I charge with 7.68 kW (the full 32 A) and my JuiceBox J-1772 supports up to 40 A (9.6 kW, or 80% of 50 A outlet).

Oversubscribing a multi-outlet circuit is a common cause of house fires, because there is no practical way to prevent drawing more than 80% of 15 A, for example. I had an ancient wire nut burn in my attic last year and the insulation around it was singed. I'm really lucky we have flammability standards for insulation. Circuits 30 A and above typically only run to a single outlet/appliance so that isn't a problem. At 50 A and above, a charger should be hard wired without a plug, which I assume your Tesla charger is!

But I digress... we'll probably never have CCS at home.

[Crissa]

CCS is just an external charger, it can run at low wattage.

So yeah, we could just have it at home.  That would be a bit bulky of a granny cable, tho!

-Crissa

[Curt]

CCS is just an external charger, it can run at low wattage.

So yeah, we could just have it at home.  That would be a bit bulky of a granny cable, tho!

And expensive, $9000 for this 25kW one.
But aren't all plug-in chargers granny cables, if you neglect to mount them on the wall?

[DonTom]

The 6.6 kW connector you mentioned is from 19 years ago. I charge with 7.68 kW (the full 32 A) and my JuiceBox J-1772 supports up to 40 A (9.6 kW, or 80% of 50 A outlet).

Mainly when I am on the road is when I care what they can support. I just purchased  a couple of 3.3 KW chargers and with the OBC that will be 7.9 KW. Or one in parallel with my Elcon 2500 will be 7.1 KW. That's  still a little over what many J stations can handle while on the road these days. But I can always charge at 4.6 KW if there is an issue.

At 50 A and above, a charger should be hard wired without a plug, which I assume your Tesla charger is.

Yep! I didn't install any of them, I let an electrician do them.

But I digress... we'll probably never have CCS at home.

I don't see much need for home fast DC charging here.  On the road is a much different story,

I will soon be able to charge my SR at home at ten KW (OBC, plus two 3.3KW Elcons plus two 1 KW Delta-Qs') if I am in a hurry, using my Tesla-Tap.  And I doubt I will do that often, if ever.

I will use my two old Elcons on my DS and charge it at 6.3 KW which is getting close to 1C on that bike.

-Don-  Reno, NV

[Crissa]

CCS is just an external charger, it can run at low wattage.

So yeah, we could just have it at home.  That would be a bit bulky of a granny cable, tho!

And expensive, $9000 for this 25kW one.

But you don't need 25kW at the house, so you'd probably choose a lower-power version ;

-Crissa

[DonTom]

I didn't say or imply all J1772 stations are 32 A.

I've never seen a 19.2 KW J1772, but that is the spec maximum, not "The issue is the J1772 plug itself. Only approved for 6.6 KW."

The Chargpoint I used yesterday said it was "6.6 KW per port " and had two ports. So that means that J-station  can do 13.2 KW (or up to 55 amps). I am glad to see that the newer charge stations don't drop the power when two vehicles are charging from the same two-port station. This means I can charge from this station at all the power I want as I can use both ports from the same station. This new J-1772  stuff getting as good as most Tesla destination chargers at least when I can hog them both.


-Don-  Auburn, CA

[JaimeC]

My company went on the "cheap" because the Chargepoint stations in our parking lot only deliver the full 6.6kW if only one vehicle is hooked up.  If a second one is hooked up they each get a maximum of 3.3kW.  Still, that's better than nothing and as I was stuck at my desk even 3.3kW is fast enough for me to disconnect after our two-hour limit in the spot has expired (not that all of our employees observe that limitation).

Since the pandemic, though, most of my charging is once again overnight in my garage... but usually only once a week.  Occasionally more often if I meet friends for a dinner ride after work.  Weekends I take advantage of all of the L2 stations in my area for longer rides.