What's with all the 6 kW public L2 chargers? Why is it so rare to find faster AC charging options?

[Earl]

Shocked, shocked I am

Don't forget, I consider myself to be an EVangelist so many of my attitudes and pushes are not necessarily in support of my own interests or those of EV diehards, but, rather of those who do not yet drive EVs, many of whom see them as being a hassle. Therefore, I push back on measures by the diehards that could likely be seen as a hassle.
Having to get up in the middle of the night, during work, dinner, a movie, a play, a baseball game, etc, to move one's car count as hassles for many. So does having to wait for and sit at a fast charger after any of the above activities in order to get enough charge to get home or on one's way.
I'd rather push for realistic expectations (ie, "one charger is not enough") rather than accept that EVs will always be a hassle.
I also push back on diehards with plenty of time on their hands who keep saying that it is good to drive slowly and take a long time to get places with EVs.

 

[ewoodrick]

208v -vs- 240v is basically a rounding error. They're basically the same thing with it comes to charging speed. Its the current that matters.

Sure there is: It is 8 amps at 120 volts = 0.960 KW which is ~ 1 KW. A lot of EVs had their "Level 1" limit set at 8 amps to minimize problems when folks try to plug into wall outlets that share other loads.

If 15% is a rounding error, which digit are you rounding?

Show me a mechanism that can limit a 120V socket to 8A. Plug pretty much any car on the market today into the plug and it's going to go to 12A (80% of the NEMA 15-20 socket).
Give me an example of a EV that limited L1 charging to 8A.

 

[stopcrazypp]

If 15% is a rounding error, which digit are you rounding?

Show me a mechanism that can limit a 120V socket to 8A. Plug pretty much any car on the market today into the plug and it's going to go to 12A (80% of the NEMA 15-20 socket).
Give me an example of a EV that limited L1 charging to 8A.

Probably talking about the Bolt, which likes to default back to 8A when charging on L1.
Charging Rate Keeps Defaulting to 8 Amps

It appears to be a carry over from the Volt days, when they had problems with melting plugs (which is why they introduced the 8A default limit):
'The Truth About Cars' Article on the 2013 8A...

 

[ewoodrick]

Probably talking about the Bolt, which likes to default back to 8A when charging on L1.
Charging Rate Keeps Defaulting to 8 Amps

It appears to be a carry over from the Volt days, when they had problems with melting plugs (which is why they introduced the 8A default limit):
'The Truth About Cars' Article on the 2013 8A...

Interesting, but that's limited in the vehicle, not the socket.

 

[3sr+buyer]

If 15% is a rounding error, which digit are you rounding?

Show me a mechanism that can limit a 120V socket to 8A. Plug pretty much any car on the market today into the plug and it's going to go to 12A (80% of the NEMA 15-20 socket).
Give me an example of a EV that limited L1 charging to 8A.

Chevrolet Bolt does 120V charging at either 8A or 12A, with 8A being the default, probably because GM thought that many older houses' garage outlets are shared with other outlets that may have devices with significant current draw (so using 12A or 80% of the 15A circuit could cause circuit breakers or fuses to pop, or worn out or poorly installed outlets to overheat).

Recent electrical codes require new garage outlets to include a 20A dedicated outlet for each parking space, but those codes are very new so that they do not affect many garages yet, and not all places have moved to those newer codes.

 

[stopcrazypp]

Interesting, but that's limited in the vehicle, not the socket.

Yes, which is exactly what the comment you were responding to said. It never said it was set at the socket.

If you must set a limit on the socket end, the EVSE would need to be installed with the outlet and set to the 8A limit on the EVSE side.

 

[Earl]

Interesting, but that's limited in the vehicle, not the socket.

Yep, that's what I said. I mentioned nothing about the socket.
It's a practical problem with using a normal outlet to charge a car. That was one of the reasons that the NEC and SAE pushed so hard for EVSEs instead of counting on wall outlets.

 

[Earl]

If 15% is a rounding error, which digit are you rounding?

Chill out dude!

Besides, it's actually 240v +- 10% or something thereabouts. Therefore 240v can be as low as ~216v. 208v isn't much below that.

I've used many 240v and 208v EVSEs over the decades and it really doesn't matter that much. Ambient temperature and driving speed will affect your charging MPH as much or more than the supply voltage.

 

[Ben W]

This discussion is relevant for an edge case I currently have, which is that my 2008 Roadster is currently sitting at Gruber Motors in Phoenix after having some work done, and I would love to drive it from there to my home in Los Angeles if I could conveniently do so. The car supports 16kW charging (240v@70A), but as noted there are very few public 16kW chargers.

Buckeye, AZ and Blythe, CA each have slow 6kw chargers, but there's a completely empty 123mi stretch in between, which would be dicey but possible with the Roadster's ~200mi rated range on 100% charge. (It's still on its original battery, degraded ~20% from the original 244mi capacity.) From Blythe it's ~100mi to Indio, where there are 16kW destination chargers, but it would take overnight charging on Blythe's 6kW charger to make this stretch comfortably. So I'd have to leave Phoenix in the morning, top up to 100% in Buckeye (a few hours), hypermile to Blythe, top up to 100% again overnight, then drive to Indio and "fast" charge for 3 hours to continue 140 more miles and coast into LA on electrical fumes. (Plenty of charging options near LA for the home stretch if needed.) What do you think, is this a terrible idea?

 

[Earl]

This discussion is relevant for an edge case I currently have, which is that my 2008 Roadster is currently sitting at Gruber Motors in Phoenix after having some work done, and I would love to drive it from there to my home in Los Angeles if I could conveniently do so. The car supports 16kW charging (240v@70A), but as noted there are very few public 16kW chargers.

Buckeye, AZ and Blythe, CA each have slow 6kw chargers, but there's a completely empty 123mi stretch in between, which would be dicey but possible with the Roadster's ~200mi rated range on 100% charge. (It's still on its original battery, degraded ~20% from the original 244mi capacity.) From Blythe it's ~100mi to Indio, where there are 16kW destination chargers, but it would take overnight charging on Blythe's 6kW charger to make this stretch comfortably. So I'd have to leave Phoenix in the morning, top up to 100% in Buckeye (a few hours), hypermile to Blythe, top up to 100% again overnight, then drive to Indio and "fast" charge for 3 hours to continue 140 more miles and coast into LA on electrical fumes. (Plenty of charging options near LA for the home stretch if needed.) What do you think, is this a terrible idea?

That is certainly doable. I did a 600 mile roadtrip 2 years ago in our Roadster. It took a lot of patience and one overnight stop but did work.

 

[wws]

This discussion is relevant for an edge case I currently have, which is that my 2008 Roadster is currently sitting at Gruber Motors in Phoenix after having some work done, and I would love to drive it from there to my home in Los Angeles if I could conveniently do so. The car supports 16kW charging (240v@70A), but as noted there are very few public 16kW chargers.

Buckeye, AZ and Blythe, CA each have slow 6kw chargers, but there's a completely empty 123mi stretch in between, which would be dicey but possible with the Roadster's ~200mi rated range on 100% charge. (It's still on its original battery, degraded ~20% from the original 244mi capacity.) From Blythe it's ~100mi to Indio, where there are 16kW destination chargers, but it would take overnight charging on Blythe's 6kW charger to make this stretch comfortably. So I'd have to leave Phoenix in the morning, top up to 100% in Buckeye (a few hours), hypermile to Blythe, top up to 100% again overnight, then drive to Indio and "fast" charge for 3 hours to continue 140 more miles and coast into LA on electrical fumes. (Plenty of charging options near LA for the home stretch if needed.) What do you think, is this a terrible idea?

RV parks could give you 10 kW, instead of 6 kW via their 14-50 receptacles.

 

[Genie]

RV parks could give you 10 kW, instead of 6 kW via their 14-50 receptacles.

But mobile connector only allows 32A (<8kW)

 

[wws]

But mobile connector only allows 32A (<8kW)

Gen 1 UMC does a full 40 amps. There are others on the market as well.

 

[ewoodrick]

This discussion is relevant for an edge case I currently have, which is that my 2008 Roadster is currently sitting at Gruber Motors in Phoenix after having some work done, and I would love to drive it from there to my home in Los Angeles if I could conveniently do so. The car supports 16kW charging (240v@70A), but as noted there are very few public 16kW chargers.

Buckeye, AZ and Blythe, CA each have slow 6kw chargers, but there's a completely empty 123mi stretch in between, which would be dicey but possible with the Roadster's ~200mi rated range on 100% charge. (It's still on its original battery, degraded ~20% from the original 244mi capacity.) From Blythe it's ~100mi to Indio, where there are 16kW destination chargers, but it would take overnight charging on Blythe's 6kW charger to make this stretch comfortably. So I'd have to leave Phoenix in the morning, top up to 100% in Buckeye (a few hours), hypermile to Blythe, top up to 100% again overnight, then drive to Indio and "fast" charge for 3 hours to continue 140 more miles and coast into LA on electrical fumes. (Plenty of charging options near LA for the home stretch if needed.) What do you think, is this a terrible idea?

My recommendation, get off the Interstates and stay at slower speeds on the surface roads.
In another Tesla, I'd look to maximize the range by optimizing the speed. The Model 3 at just over 300 miles range has been known to go 600 miles at 35 mph.
In this case, I dare say that going slower will make you go faster.

 

[Earl]

But mobile connector only allows 32A (<8kW)

The Roadster Universal Mobile Connector provides 40A from a NEMA 14-50.

My recommendation, get off the Interstates and stay at slower speeds on the surface roads.

There aren't a lot of roads other than interstate along much of this route.

 

[ewoodrick]

The Roadster Universal Mobile Connector provides 40A from a NEMA 14-50.

There aren't a lot of roads other than interstate along much of this route.

Oh yea, whoops. I was thinking more SanFran-LA.
But still follow behind the slow trucks instead of passing them by.

I remember with my 88 mph Leaf. It was enough range to get me downtown and back in some situations. I learned to hate it when the traffic was going fast, as I knew I was going to have to stop coming home. But when the traffic was slow, I could easily do it.
Find someone with a Cybertruck to go with you, then you can stop and steal some charge a little more often.

 

[Ben W]

My recommendation, get off the Interstates and stay at slower speeds on the surface roads.
In another Tesla, I'd look to maximize the range by optimizing the speed. The Model 3 at just over 300 miles range has been known to go 600 miles at 35 mph.
In this case, I dare say that going slower will make you go faster.

I recall running the numbers vis-a-vis 16kW charging, and concluding that 60mph was about the Roadster's sweet spot for long-distance travel. With 6kW charging the optimal speed would be somewhat less, maybe 40mph. My highway strategy would probably be to find a slow semi truck and draft behind it, which would maybe add back a bit of efficiency, if it doesn't irritate the semi driver too much! I'm not sure whether there's a practical surface-road or access-road route from Phoenix to LA, but perhaps for some stretches there is.

 

[Ben W]

Well, it looks like the Phoenix -> LA trip is infeasible after all, but not for any of the reasons discussed. The limiting factor turns out to be heat; Gruber advised me that an extended drive across the Mojave in hot conditions (>90 deg) is liable to overheat and temporarily brick the car, so it would be much safer to wait until the weather cools down again (like November) before attempting it. So I'll likely have it shipped to LA, alas. Oh well, it was a fun idea!

 

[ewoodrick]

Well, it looks like the Phoenix -> LA trip is infeasible after all, but not for any of the reasons discussed. The limiting factor turns out to be heat; Gruber advised me that an extended drive across the Mojave in hot conditions (>90 deg) is liable to overheat and temporarily brick the car, so it would be much safer to wait until the weather cools down again (like November) before attempting it. So I'll likely have it shipped to LA, alas. Oh well, it was a fun idea!

Bummer, of course stopping in the desert would have been a MUCH bigger bummer.

 

[Earl]

Well, it looks like the Phoenix -> LA trip is infeasible after all, but not for any of the reasons discussed. The limiting factor turns out to be heat; Gruber advised me that an extended drive across the Mojave in hot conditions (>90 deg) is liable to overheat and temporarily brick the car, so it would be much safer to wait until the weather cools down again (like November) before attempting it. So I'll likely have it shipped to LA, alas. Oh well, it was a fun idea!

That's probably sage advise. I just did the run from Phoenix to LA today (in Model 3) and never saw temp above 89F but it was definitely close. Remember that Tesla engineers first solved the hardest problem (batteries), then the 2nd hardest problem (motor), then they had to ship product so they rushed the PEM (Power Electronic Module). It does not have sufficient cooling capabilities.
Needless, to say, the 1st Model S had 2 HVAC systems, one for the people, the other for the power plant including power electronics.