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

[J-a-x]

In the city of Boston there are hundreds of public L2 chargers, however there are probably 5 in the entire city which are greater than 6 kW. I see the same trend for pretty much all of New England and New York and Ontario. There are Superchargers and other L3 chargers like Electrify America and EVgo which are more expensive and typically located along highways, but the more affordable L2 chargers in public parking areas are almost always 6 kW. It would be such a huge benefit to have 19 kW L2 chargers in all these places so you could actually get more than 5% when you are out doing errands.

I know that L2 AC chargers can get as high as ~19 kW, so why is it that only 6 kW chargers seem to exist? 6 kW chargers are useful and better than nothing but they take so long to charge your car that people who rely on them often sit on them for 8-10 hours which means they are never free. I can totally understand a 6 kW in your personal garage because it would be perfect overnight, but I can't understand why the city would install these at public locations when faster chargers exist.

Were there technical limitations years ago when these stations were installed and that's why today we have so many slow L2 chargers (I've only owned an EV for a year)?
Are there limitations of the infrastructure that can't support more than 25 amp power?
Are L2 chargers at >6 kW just ridiculously expensive? Interestingly I still see ChargePoint selling more 6 kW systems than anything...

Does anybody know of a city have newer public L2 chargers which are > 6 kW? Just curious if this is happening anywhere...

The city of Boston is apparently planning new wave of L2 infrastructure in the city, modeled after NYC, but that does not give me much hope because NYC has way too few L2 chargers (for example 4 in all of the upper west side with 200k+ people living there) and of course they're all 6 kW so people park there for 8-10 hours and they are never free.

 

[miimura]

You should be more selective about your use of the word "Free". Lots of stations are never free but always available. Conversely, stations that are always free are rarely available.

Back to original topic. I think high power AC charging is a weird in-between use case that is hard to justify. I think 6kW L2 is perfectly usable because most people either want to park for their entire work day or overnight. For those use cases, 30A 6kW L2 is totally appropriate. I think other use cases like opportunity charging during shopping is probably better served with low power DCFC like power split stalls that average 25 to 50kW per cable.

 

[J-a-x]

Sorry, I meant available. I thought it made sense in context…

 

[J-a-x]

You should be more selective about your use of the word "Free". Lots of stations are never free but always available. Conversely, stations that are always free are rarely available.

Back to original topic. I think high power AC charging is a weird in-between use case that is hard to justify. I think 6kW L2 is perfectly usable because most people either want to park for their entire work day or overnight. For those use cases, 30A 6kW L2 is totally appropriate. I think other use cases like opportunity charging during shopping is probably better served with low power DCFC like power split stalls that average 25 to 50kW per cable.

I guess it depends on cost, right? If a split DC station costs $75k for 2 cables and requires a new transformer, and a 19 kW AC stations costs $20k for 2 cables, the AC station might be the one that gets built You’d also think the station operators would want stations faster than 6 kW because faster stations means more kWh which means more profit, as long as the initial investment isn’t too high.

But I rarely see either in this part of the country. It’s most usually 75+ kW DC (Supercharger, EVGo etc) on the highway or 6 kW L2 on city streets or shopping centers

I would have thought a faster L2 might meet the sweet spot between speed, cost, and ease of installation with existing infrastructure…

 

[LoudMusic]

I'm annoyed by the underwhelming speeds of the majority of L2 sites as well. 6kW is definitely the most common. They are likely 208V30A (6.2kW) because that's a super cheap electrical install.

However, the peak that the standard supports, 19kW, is also largely unnecessary with the existing production vehicles. Very few cars can use more than 11.5kW. I don't know how they settled on that, but it's 240V48A (48 is 80% of 60, which could be a common breaker in a home AC panel). So that's probably why.

I'd love to see a row of 11kW chargers at parks, sports venues, theaters, malls, grocery stores, etc. It would create reliable places for people to charge their vehicles who are unable to charge at home or work.

With the advancement toward vehicles with bigger batteries, like Rivian's R1 series, the Cybertruck, Chevy's Silverado EV, even hotels are going to need to move to 11kW charging in order for it to really appeal to those drivers. A 130kWh battery at 11kW needs nearly 12 HOURS to get a full charge. If I'm driving long distance I'm not staying at a hotel that long. 10 hours is my max. 6kW would net about 60kWh which is a pretty great gain on a 75kWh battery, but it's not impressive for the vehicles with big batteries.

In another ten years batteries might be cracking 300kWh for electric vehicles replacing massive SUVs and minivans. At that point you might have to have low end DCFC overnight to get a full battery after a day of driving.

 

[J-a-x]

I'm annoyed by the underwhelming speeds of the majority of L2 sites as well. 6kW is definitely the most common. They are likely 208V30A (6.2kW) because that's a super cheap electrical install.

However, the peak that the standard supports, 19kW, is also largely unnecessary with the existing production vehicles. Very few cars can use more than 11.5kW. I don't know how they settled on that, but it's 240V48A (48 is 80% of 60, which could be a common breaker in a home AC panel). So that's probably why.

I'd love to see a row of 11kW chargers at parks, sports venues, theaters, malls, grocery stores, etc. It would create reliable places for people to charge their vehicles who are unable to charge at home or work.

With the advancement toward vehicles with bigger batteries, like Rivian's R1 series, the Cybertruck, Chevy's Silverado EV, even hotels are going to need to move to 11kW charging in order for it to really appeal to those drivers. A 130kWh battery at 11kW needs nearly 12 HOURS to get a full charge. If I'm driving long distance I'm not staying at a hotel that long. 10 hours is my max. 6kW would net about 60kWh which is a pretty great gain on a 75kWh battery, but it's not impressive for the vehicles with big batteries.

In another ten years batteries might be cracking 300kWh for electric vehicles replacing massive SUVs and minivans. At that point you might have to have low end DCFC overnight to get a full battery after a day of driving.

I’ve been working with my HOA to upgrade the 6 kW L2 chargers in the shared charging area of our garage with something faster. As with the shopping center example, its a not good that the average EV driver in my garage takes 10 hours to charge form 20 to 80 because it means people leave there cars there all day and block the chargers for other drivers. And don’t get me started about all the people who insist on charging to 100% then sit idle for an extra 10 hours…

Anyway, I suggested to the board a 12 kW charger from ChargePoint (as well as a few other 12 kW options) which I said was probably the sweet spot in terms of price and functionality, but an F-150 Lightning driver saw my email told them that the only charger that makes sense is 19 kW and that’s what he has at his “other house” and that’s the only charger he will use for his truck and was very demanding about it and dismissive about my initial suggestions (and imo he was very rude, basically trying to contradict everything that I said rather than work together). I held back because I didn’t want to start an email war, but I was skeptical about his 19 kW comment.

I just looked up the F-150 Lightning and like my model Y it maxes out AC charging at about 12 kW. I didn’t even realize this limitation existed on the EV side, but I did know I’d never charged faster than that and had always assumed I just hadn’t had a chance to charge with the latest hardware. Just thought it was kind of funny to realize I was right at the start and this guy was out of line.

 

[ewoodrick]

In the city of Boston there are hundreds of public L2 chargers, however there are probably 5 in the entire city which are greater than 6 kW. I see the same trend for pretty much all of New England and New York and Ontario. There are Superchargers and other L3 chargers like Electrify America and EVgo which are more expensive and typically located along highways, but the more affordable L2 chargers in public parking areas are almost always 6 kW. It would be such a huge benefit to have 19 kW L2 chargers in all these places so you could actually get more than 5% when you are out doing errands.

I know that L2 AC chargers can get as high as ~19 kW, so why is it that only 6 kW chargers seem to exist? 6 kW chargers are useful and better than nothing but they take so long to charge your car that people who rely on them often sit on them for 8-10 hours which means they are never free. I can totally understand a 6 kW in your personal garage because it would be perfect overnight, but I can't understand why the city would install these at public locations when faster chargers exist.

Were there technical limitations years ago when these stations were installed and that's why today we have so many slow L2 chargers (I've only owned an EV for a year)?
Are there limitations of the infrastructure that can't support more than 25 amp power?
Are L2 chargers at >6 kW just ridiculously expensive? Interestingly I still see ChargePoint selling more 6 kW systems than anything...

Does anybody know of a city have newer public L2 chargers which are > 6 kW? Just curious if this is happening anywhere...

The city of Boston is apparently planning new wave of L2 infrastructure in the city, modeled after NYC, but that does not give me much hope because NYC has way too few L2 chargers (for example 4 in all of the upper west side with 200k+ people living there) and of course they're all 6 kW so people park there for 8-10 hours and they are never free.

Are they showing 240V or 120V? Are they free or do you have to pay. If they are free, then stop complaining to the gift horse.

Free L2 chargers aren't really intended for people to do a 20-80% fill up, just a top-off.

 

[3sr+buyer]

I just looked up the F-150 Lightning and like my model Y it maxes out AC charging at about 12 kW. I didn’t even realize this limitation existed on the EV side

Yes, ~7kW AC charging limitation at the EV is not rare. Model 3 SR/SR+/RWD is one example. Nissan Leaf is another.

 

[ewoodrick]

I’ve been working with my HOA to upgrade the 6 kW L2 chargers in the shared charging area of our garage with something faster. As with the shopping center example, its a not good that the average EV driver in my garage takes 10 hours to charge form 20 to 80 because it means people leave there cars there all day and block the chargers for other drivers. And don’t get me started about all the people who insist on charging to 100% then sit idle for an extra 10 hours…

Anyway, I suggested to the board a 12 kW charger from ChargePoint (as well as a few other 12 kW options) which I said was probably the sweet spot in terms of price and functionality, but an F-150 Lightning driver saw my email told them that the only charger that makes sense is 19 kW and that’s what he has at his “other house” and that’s the only charger he will use for his truck and was very demanding about it and dismissive about my initial suggestions (and imo he was very rude, basically trying to contradict everything that I said rather than work together). I held back because I didn’t want to start an email war, but I was skeptical about his 19 kW comment.

I just looked up the F-150 Lightning and like my model Y it maxes out AC charging at about 12 kW. I didn’t even realize this limitation existed on the EV side, but I did know I’d never charged faster than that and had always assumed I just hadn’t had a chance to charge with the latest hardware. Just thought it was kind of funny to realize I was right at the start and this guy was out of line.

You seem to be thinking that a full charge is a common occurrence, it's actually quite rare for someone to use even 30% of their battery in a day. 6kW is usually much more than is needed.

And yes, the charger is actually in the car and 11kW is basically what is the max available in most homes. That's a 60A breaker and nearly a third of a 200A panel.

 

[J-a-x]

Are they showing 240V or 120V? Are they free or do you have to pay. If they are free, then stop complaining to the gift horse.

Free L2 chargers aren't really intended for people to do a 20-80% fill up, just a top-off.

Usually $0.30 per kWh around here. Occasionally free but extremely rare.

 

[J-a-x]

Yes, ~7kW AC charging limitation at the EV is not rare. Model 3 SR/SR+/RWD is one example. Nissan Leaf is another.

Why are there even 19.2 kW chargers on the market. I did a bit of googling but couldn’t find any cars that have 19.2 kW onboard chargers including the Cybertuck which has a huge battery.

 

[J-a-x]

You seem to be thinking that a full charge is a common occurrence, it's actually quite rare for someone to use even 30% of their battery in a day. 6kW is usually much more than is needed.

And yes, the charger is actually in the car and 11kW is basically what is the max available in most homes. That's a 60A breaker and nearly a third of a 200A panel.

For those of us who live in places without our won dedicated chargers, getting a large charge while on the go can be more common than you might think. The fact that there are cars hogging all the L2 chargers in town for 10 hours at a time is evidence that people need a lot of time to get the energy they require withthese 6 kW stations.

A good example of this for me is when I visit my sister in NYC. The parking is all parallel street parking only. There are 4x 6kW chargers per 200k residents and most people leave their cars on the charger for 10+ hours at a time when they can get one because they don’t know when they will have a chance again. On the rare occasion I’ve been able to get a 6 kW charger (once out of maybe 6 visits) I left my car there maybe 6 or 8 hours to get enough energy to return to Boston. It would be much better if it took half that long.

You’d be amazed at how many houses in Boston are built without private driveways or garages. The majority of residents here in Charlestown park on the street. I happen to have a garage at least, but my garage has 300 cars and only 5x 6kW chargers so i sometimes find it useful to get a good charge when I’m out because there’s no guarantee I can do so at home… When I’m lucky to get an L2 charge while shopping I usually only get 5% or so…

 

[ewoodrick]

Why are there even 19.2 kW chargers on the market. I did a bit of googling but couldn’t find any cars that have 19.2 kW onboard chargers including the Cybertuck which has a huge battery.

I think that the F-150 Lightning may be able to use it.

So many people think that bigger is better and there are manufacturers out there to allow people to spend the money. Some Teslas did have the ability many years ago, but they dropped it.

I charge two Teslas alternating access to a 1.5kW plug. I rarely use public L2 charging, I rarely stay in one place long enough to add enough miles to warrant plugging in, just wait until I get home.

 

[LoudMusic]

Why are there even 19.2 kW chargers on the market. I did a bit of googling but couldn’t find any cars that have 19.2 kW onboard chargers including the Cybertuck which has a huge battery.

I thought the Porsche Taycan could but that doesn't seem to be the case either.
Older models of Model S had a single 40A charger and an option for a second 40A charger. That would get you to the 19.2kW charge rate if you had an L2 charger that could deliver it. Eventually they dropped that option and started using single 48A charger.

The F150 Lightning 'standard' battery pack has a 48A charger (11.3kW), but the 'extended' battery pack vehicle has two 40A chargers on board to get to that 19.2kW of charge rate.

GMC Hummer EV has 80A 19.2kW charging.

I'm pretty sure there are some others, I just can't think of them.

With batteries getting bigger we might actually see more vehicles with dual 40A chargers. It would also be nice to have redundancy built in. There certainly have been plenty of charger failure reports even on this forum.

 

[J-a-x]

I thought the Porsche Taycan could but that doesn't seem to be the case either.
Older models of Model S had a single 40A charger and an option for a second 40A charger. That would get you to the 19.2kW charge rate if you had an L2 charger that could deliver it. Eventually they dropped that option and started using single 48A charger.

The F150 Lightning 'standard' battery pack has a 48A charger (11.3kW), but the 'extended' battery pack vehicle has two 40A chargers on board to get to that 19.2kW of charge rate.

GMC Hummer EV has 80A 19.2kW charging.

I'm pretty sure there are some others, I just can't think of them.

With batteries getting bigger we might actually see more vehicles with dual 40A chargers. It would also be nice to have redundancy built in. There certainly have been plenty of charger failure reports even on this forum.

I see, so there are a few but not many by the sounds of it. So dual 40A systems both charging different cells simultaneously? Is that how it works?

 

[miimura]

I see, so there are a few but not many by the sounds of it. So dual 40A systems both charging different cells simultaneously? Is that how it works?

No, it's just two chargers operating in parallel pushing current into the same (+) and (-) terminals on the high voltage battery.

 

[miimura]

I’ve been working with my HOA to upgrade the 6 kW L2 chargers in the shared charging area of our garage with something faster. As with the shopping center example, its a not good that the average EV driver in my garage takes 10 hours to charge form 20 to 80 because it means people leave there cars there all day and block the chargers for other drivers. And don’t get me started about all the people who insist on charging to 100% then sit idle for an extra 10 hours…

I would suggest that you should have high powered chargers in a section of the parking where you have to move your car, like visitor parking. The 6kW chargers should go in assigned parking stalls or long dwell where people are expecting to leave the car overnight or all day long. In fact, I would argue that you should oversubscribe those long dwell chargers with power sharing. For example, put 10 stations on a 200 amp feeder. Chances are there will never be 10 people charging at the same time. In fact, you can set them up so that they can go up to 48amps, but they share the power. If everyone plugged in at the same time they will only get like 3.3kW, but in reality that will never happen.

 

[stopcrazypp]

Are they showing 240V or 120V? Are they free or do you have to pay. If they are free, then stop complaining to the gift horse.

Free L2 chargers aren't really intended for people to do a 20-80% fill up, just a top-off.

Bingo, those chargers are only for a top off, in which case 6kW is plenty good enough. And before the advent of power sharing, the lower power also means that they can install more stalls for the same power service. And even with power sharing, the conductor costs go up when higher power is used, especially for longer runs.

For 6 kW (namely 240V@25A, using a 30A breaker), you only need 10/2 romex, which is $0.96/ft:
Southwire 250 ft. 10/2 Solid Romex SIMpull CU NM-B W/G Wire 28829055 - The Home Depot

@J-a-x seems to now be aware of why 19kW makes no sense (because few cars have a 19kW on-board charger which is the bottleneck). But let's even assume the more common 11.5kW (namely 240V@48A, using a 60A breaker).
The options are limited there too as the following reddit discusses:

https://www.reddit.com/r/evcharging/comments/u0noy7/6_awg_wire_too_small_for_48a_charging

If you run Romex, you need 4awg, and that's typically only made in 4/3 (which you have an extra conductor wasted). That costs $13.49/ft. So for less than 2x the power 14x the price in the wiring!
Southwire 500 ft. 4/3 Stranded Romex SIMpull CU NM-B W/G Wire 63968205 - The Home Depot

If you run THHN in conduit, you can use 6awg (one black, one red, one 8awg ground), which works out to $1.58+1.21+0.50+$1/ft conduit= $4.29/ft
Southwire 1000 ft. 4 Black Stranded CU SIMpull THHN Wire 20499004 - The Home Depot
Cerrowire 500 ft. 8 Gauge Green Stranded Copper THHN Wire 112-4005J - The Home Depot
Search Results for conduit cost at The Home Depot
That's still 4.5x the price.

 

[Earl]

Why are there even 19.2 kW chargers on the market. I did a bit of googling but couldn’t find any cars that have 19.2 kW onboard chargers including the Cybertuck which has a huge battery.

The original Tesla Roadster and early Model S supported ~20 KW AC charging. That was before DC Fast Charging (Supercharging) was a thing.
There has always been a tradeoff between AC and DC charging. It actually is a tradeoff between onboard and off-board chargers. With AC charging, one carries the actual charger (the thing that converts AC to DC at the right current and voltage for the battery) on the car so you can just plug it into any AC source and charge. With DC or off-board charging, the charger is at the point where you charge and it serves the right amount of DC to the car's battery.
A lot of it comes down to utilization and economics:
With a shared charging location, off-board chargers make sense since many cars can benefit from the investment in a single charger. Larger, more powerful chargers are more expensive but one spends less time using them. Therefore, off-board makes a lot of sense since many people can share the costs.
With dedicated charging locations (eg, one's overnight or workplace charging location), the charger will be tied up most of the time anyway so there will be nearly a 1:1 ratio of chargers and cars so the economics of where the charger is aren't as obvious. However, having the charger with you all the time means one can easily plug in to relatively cheap AC outlets that others may provide so it is good to have a charger of some size, onboard every vehicle.
In the 1st modern wave of EV (late 1990's), the early GM EV1 and S10 as well as the Toyota RAV4EV relied on off-board chargers while the Ford Th!nk and Ranger and Honda EV+, relied on off-board charging similar to today's J-1772/HPWC. All charged at around 6 KW. Only the Hyundai and Chrysler at the time supported fast charging and only in very few locations (Los Angeles-LAX and Honolulu, IIRC) so that wasn't really an issue back then.
See Gen 2+ portable for the efforts early RAV4EV folks had to go to in order to make their off-board chargers portable to be able to use existing AC outlets on the road.
After the auto industry managed to kill that 1st round and Tesla jump-started a new wave of EVs, Tesla chose to support as much AC (onboard) charging as reasonable since there was no infrastructure to be able to count on. ~20 KW made sense since it was fairly easy to get a 240V/70A AC line in most places but it would also work on more easily available 240V/30A or lower circuits too.
GM and Nissan, the other EV promoters at the time, were pushing to minimize EV charging to only~3 KW and DC Fast Charging to ~50 KW. The excuse for ~3KW was that it could use existing wiring that can already handle 16 amps - in the USA, one just need to change to a 240A breaker, in Europe, it is standard for normal outlets. Conveniently, this slow charging pretty much required that one have an ICE for any serious driving since 3KW isn't enough to go more than about 40 miles in a day and 50 KW is so slow that roadtrips in an EV are ridiculously slow due to charging times. 3KW is about 13 mph charging so, overnight, one can get about 100 miles of range - fine for nearly all daily usage so it is generally usable but offers little flexibility.
Another good reason for faster daily charging is to be able to take advantage of lower charging rates. If one must spend a lot of time charging then one cannot time one's charging to coincide with spare or cheaper electricity capacity.
The early compliance EVs in CA that only supported 3KW showed how limited this was (with negligible cost savings), however, ~6KW seemed to be a reasonable compromise to be able to get a reasonable distance overnight so it has kind of stuck. I suspect Chargepoint's standardization on ~6KW also strengthened that amount.
I hope this bit of history and 1st principles look helps folks to understand why we have what we have. It may change in the future as humanity learns how, best, to use EVs.
The next point of contention that was hashed-out in the 1990's is inductive -vs- conductive charging but that's a different story for a different day.

 

[FatFalcon]

I thought the Porsche Taycan could but that doesn't seem to be the case either.
Older models of Model S had a single 40A charger and an option for a second 40A charger. That would get you to the 19.2kW charge rate if you had an L2 charger that could deliver it. Eventually they dropped that option and started using single 48A charger.

The F150 Lightning 'standard' battery pack has a 48A charger (11.3kW), but the 'extended' battery pack vehicle has two 40A chargers on board to get to that 19.2kW of charge rate.

GMC Hummer EV has 80A 19.2kW charging.

I'm pretty sure there are some others, I just can't think of them.

With batteries getting bigger we might actually see more vehicles with dual 40A chargers. It would also be nice to have redundancy built in. There certainly have been plenty of charger failure reports even on this forum.

19kw AC charging is an option for the Taycan, FYI.

19kw charging is just such a niche case in the US... Few cars can do it, few people want it, almost nobody needs it... I would rather the industry focus on large-scale deployment of cheap 6kw AC chargers. If someone has regular access to any EV charging solution of any sort it makes EV ownership an easy switch. Even 3kw is ok if there are enough.