doghousePVD
My grandfather’s car
I am very happy charging my Tesla X at home at 17kw. Wish I could do it on the road more. Many destination chargers, especially at parks, are 19kw.
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What's with all the 6 kW public L2 chargers? Why is it so rare to find faster AC charging options?
- Thread starter J-a-x
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6kw is probably common because it’s likely fed by 208VAC which is a typical step-down from higher voltages that commercial buildings use. Limit it to 32 amps and you get 6.6kw or less with voltage drop.
Limiting to 32Amps is likely infrastructure and labor-based on 40A breakers and a certain tendency to not use higher gage wires. The thicker is is, the harder to run.
Limiting to 32Amps is likely infrastructure and labor-based on 40A breakers and a certain tendency to not use higher gage wires. The thicker is is, the harder to run.
Probably based on early low capacity EVs like the Leaf, or plug in hybrids like the Volt. 3kW is enough to overnight charge those vehicles.
I tired to argue to the board that for individual parking spaces we'd be ok with 1kW for charging for overnight (and multi day for people who work from home). We already have the infrastructure (120V AC outlets) and only need to run some conduits to some of the parking spaces and install a billing/metering system via smart outlets. I also tried to argue that 12 kW chargers in the shared charging bays would be good enough for those who either can't get a conduit at their space or don't want to pay for one, and also useful for guests and valet users (roughly 25% of my garage is valet with the rest being resident owned spaces)
The F150 guy shot me down saying 1 kW is useless and 6 kW is useless and only 19 kW in his personal space AND the shared charging bays should be considered. The problem with that is running the cabling to support anything more than 1 kW in our parking spaces is an infrastructure project the HOA can't afford and won't do. And if they did it would take a lot of time. So I said let's just use what we got in the parking spaces (1kW) for the residents that want it because it's cheap and easy (no need to re wire the garage) and for the rest let's install the fastest technology that is practical in the shared charging bays (11 kW). We'll see how that goes....
Sorry for the digression.
I seldom use more than about 3KW with my 3 since I share a 50 KW breaker with a Roadster and a back room in the garage with an A/C unit. It tends to work fine for my ~35 mile commute. I seldom ever use the full 19KW on the Roadster since our 19KW EVSE is outside and I usually charge the Roadster in the garage.
I do think that, with less efficient vehicles such as pickup trucks, 19KW may start be more useful for hotel destination chargers.
Most likely, some of those 120v outlets are daisy-chained and share a common (probably 20A) breaker so they really aren't viable for 1 kw charging. You may be able to utilize some of the existing conduits and wiring and save some expense but I suspect new breakers will be needed as well as some new conduits and wiring.
Major suggestion though: Since a dedicated breaker will be needed for each space, there's no reason to limit that breaker to 120v. You can probably put in a 240 v breaker and use the existing wiring. That will allow ~3.3 KW charging for about 100 miles overnight with an efficient car and about 70 miles for an F150 or other truck. Since dedicated breakers will be needed, I recommend wiring it directly to the resident's service panel so that it will be billed to each resident's regular bill. The residents should also be able to use a smart transfer switch and obviate the need to upgrade the total electricity to the complex and/or each unit. There just may not be an ability to use the dryer at the same time as charging. This will cost more initially, however, it will avoid the need for 3rd party billing infrastructure so the recurring cost will be a lot less.
This is obviously nonsense, however, anyone who lives in a Boston condo and drives an F150 is clearly compensating for something so it will likely be hard to reason with him. If there is any rationality: 19 KW should get an F150 about 400 miles in an 8-hour overnight charge. 10 KW (240v/40a - NEMA 14-50 outlet) will get about 240 miles (probably well more than nearly all daily usage), even 6 kW should get about 150 miles overnight. Trying to handle 19KW at all spaces will most likely require a major upgrade to the electrical infrastructure (new transformer). Depending on how far the F150 actually needs to drive each day, the above 3.3 KW solution may actually suffice. Otherwise, 6 KW or more will probably take more extensive ($$$) modifications, but that can be reserved for the macho guys.
Good luck though since the sociological challenge is likely to exceed the technical one.
myoda
Member
ChargePoint CP6000 80 amp deployment, Wilkinsburg Borough, PA. For a fleet of Hyundai Ioniq 5's. Each port is set up on a 100 amp breaker. The 6000 is also available in a 50 amp version. It's actually not that much more than the standard CT4000 that you see everywhere, and can charge cars much faster. It's also easier to fix with an updated modular design. The ones you see have the optional 23 ft cables. Available with a NACS connector. These are the first ones in the Pittsburgh area.
ucmndd
Well-Known Member
Faster chargers don’t really solve any of the problems with sharing, blocking stalls, cycling cars quicker, etc. people are knobs (the F150L guy referenced upthread sounds like a REAL knob) and the only way to get people to collectively do the right thing is to penalize bad behavior (i.e. idle fees).
In that case faster charging can actually be a detriment - fact of the matter is most people don’t want to get up at 2am to move their cars. They wanna plug in at night and unplug when they leave in the morning. Other side of the same coin, few want to get up in the middle of the night to move their car to a newly freed charger.
Installing a single 11-20kw charger is probably close to double the cost of a typical 6kw install. Would you rather have two 6kw chargers or one 11kw? In almost every case, I’ll take 2x6.
In that case faster charging can actually be a detriment - fact of the matter is most people don’t want to get up at 2am to move their cars. They wanna plug in at night and unplug when they leave in the morning. Other side of the same coin, few want to get up in the middle of the night to move their car to a newly freed charger.
Installing a single 11-20kw charger is probably close to double the cost of a typical 6kw install. Would you rather have two 6kw chargers or one 11kw? In almost every case, I’ll take 2x6.
myoda
Member
The cost of a single 11.5 kW is not double the cost of a typical 6kW. Not sure where you're getting that data.
ucmndd
Well-Known Member
It’s more than you imagine at commercial scale. Charging equipment itself is more expensive. Upsized conductors, conduit, code requirements that start mandating big burly disconnects, etc etc etc.
It certainly costs more. And like I said, in nearly all cases 2x 6kw units are going to be more useful in the same overall power envelope.
To add to what @Earl mentioned, apparently a lot of early funding for public L2 stations spec'd 30-32 amp charging. Combine with the common commercial voltage of 208V and you get ~6 kW. Adequate for early Volts, Leafs, and other early EVs. But less so for today's vehicles and environment.
Since Teslas had much higher power on-board chargers, wall connectors have often been installled on correspondingly higher power circuits. Private vs public funding...
As an aside, it was mildly disappointing to see that the Cybertruck only has 48 amp max L2 charging. Would have been an opportunity to reintroduce 72 amp charging like some older S/X had. But now that Tesla is mounting the OBC within the pack, perhaps there wasn't space.
Since Teslas had much higher power on-board chargers, wall connectors have often been installled on correspondingly higher power circuits. Private vs public funding...
As an aside, it was mildly disappointing to see that the Cybertruck only has 48 amp max L2 charging. Would have been an opportunity to reintroduce 72 amp charging like some older S/X had. But now that Tesla is mounting the OBC within the pack, perhaps there wasn't space.
I have to disagree with pretty much everything you said to some degree or another.
First of all, IMHO, a level 2 charger should be assumed to be a parking space and one should expect it to be occupied as long as the person parking there is doing whatever they are parked there for. Level 2 charging, also known as "Destination" or "Convenience" charging should be a convenience, not a hassle. Charging idle fees for level 2 makes EVs a hassle at best and the chargers useless most of the time as you sort of pointed out when contradicting yourself:
However, you started out as you missed the whole point by suggesting that:
as this is only true when someone artificially makes it true by charging horrible idle fees for level 2 charging.
Then this statement:
While sometimes true, usually isn't. Installation of an 11 - 20KW charger can cost nearly the same as a 6 KW or it can cost a whole lot more than 2X.
examples:
1) About the same (or within a rounding error): When we installed a new charging station in front of our house, a 20 KW charger cost about the same (within about 5%) as a 6 KW. This was partly because the existing 20 amp service panel was already overloaded, requiring us to upgrade it. Upgrading to 240 or 400 amps would have cost essentially the same since (maybe 400 amps was ~5% more than 240 amps due to material costs) the labor cost dominated the material cost. We also had to dig a trench and lay conduit out to the front. Again, labor costs dominated. Sure, the 40 amp conduit and wire would have been a little bit cheaper but the cost to dig the trench dominated so we just ran a 100 amp line. This also future-proofed since, in the future, we could replace the 100-amp EVSE with a sub panel and 2 or more smaller EVSEs that can handle more EVs.
2) A lot more: Had our service panel been in the garage and had 40A or 20A of spare capacity, a 3 or 6 (respectively) KW charging station could have been added for ~$200, however, a higher capacity one would have necessitated a service panel upgrade that could have cost the ~$1.5K that ours cost. In that case, the 10 - 20 KW system would have cost about 8X that of the lower capacity one.
3) A lot more with variation: At a relative's condo complex, the transformer feeding the complex is at capacity. While a single 40 amp circuit might fit, increasing to more would necessitate replacing the transformer and upgrading a lot of wiring and trenching. In this case, a massive upgrade is required to support charging for any significant number of spaces but going to 3 to 6 KW per space or 10 to 20 KW would cost about the same for the complex, however, there is probably enough space in the small service panels for each unit to add a 20 or 40 amp circuit but a larger one would require a larger box and there isn't really room for larger boxes so that would necessitate significant structural modifications. I'd estimate the cost per unit beyond the transformer and overall upgrade for the higher capacity to be about 10X that of lower capacity that can fit in the existing panels.
4) My company found that it cost about the same amount to install 8 6 KW charging stations as it would 2 to 4 since there was plenty of capacity and the major cost was trenching. Once everything was in place to dig a trench to a couple of parking spaces, going a bit farther wasn't going to cost much more. Higher power charging was going to affect the capacity and necessitate an upgrade. 6 KW charging is plenty to ensure everyone was charged by the time afternoon demand charges started becoming a problem in the summer, while 3 KW would have resulted in cars with long commutes charging into the afternoon, thus becoming a demand problem.
As you see, it all depends on the situation.
Good point that a lot of people miss. Commercial power distribution is different than residential. 208 VAC is coming from a 3-Phase power source where 240V/120V is coming from a single-phase power source.
There was a period where the Model X and Model S both had the option of a third charger. The Model Y and Model 3 only have ever allowed for 2. But before he Model 3 was introduced, Tesla dropped the option. That's also when the stopped selling the larger Wall Connector.
Yea, not 1 kW, 1.44 kW is a standard 120V 15A circuit.
1kW is only going to get you about 2 mph in a Model 3 or Model Y.
And there isn't any way that you can limit to just 1 kW.
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.
ucmndd
Well-Known Member
Shocked, shocked I am
I mean, this is where we fundamentally disagree and will apparently continue to. Charging spaces in public/shared environments are for charging. Not parking.
6kw is more than fast enough to give pretty much any EV on the road an acceptable charge recovery overnight. Most public/shared environments have a finite amount of power available and it can be prohibitively expensive to add more (not to mention the demand charges associated with delivering more.
Since you find it abhorrent to be considerate of shared resources and move when you're done (reinforcing my point that people at large can't be counted on to do the right thing), I struggle to think of many scenarios where a single 11-20kw charger is more useful than 2-3 6kw stations. Someone blocking a 20kw charger overnight when it only took them 3 hours to charge makes that resource unavailable to everyone. Provisioning the same 20kw of power over three stalls, allowing three different people the ability to charge overnight in a ~9 hour window without shuffling or inconvenience is a far better use of resources.
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Fun fact: The early Roadsters used AC Propulsion's patented "reductive charging", where they used the motor's windings as part of the transformer for the charging circuit. This way, 20 KW charging was easy and cheap (few additional parts needed) since the active electronics could handle way more than that.
I believe that ground isolation challenges with putting the utility ground onto the vehicle chassis posed challenges that led them to use a separate onboard charger that could easily isolate utility ground from chassis ground.
gtae07
Member
That 4/3 Romex can still find a use. I used it in my case where the wall charger was going on the next stud over from my panel; the wire had to go down out of the panel, through a stud, and up into the charger. I didn't have to install for the full 48A, but thinking ahead to possibly having a second EV I figured why not. Pulling that 3ft of Romex even with the extra useless conductor was still easier than trying to put conduit into the wall for such a short distance.
In hindsight I'm glad I had that extra amperage available--though I usually charge at a reduced rate to reduce heat and resistive loss, there have been a handful of occasions in the past year where having that 48A on tap has been very helpful. One or two cases where the car didn't start charging when it should have and I had to "catch up", and two or three cases where I had an unexpected need to go out again and was able to put enough juice in to pull it off without having to hit the local supercharger.
In the future, if we have a second EV and/or a guest, that higher amperage will be useful because it will let me finish my charging (I usually leave the house around 430) and plug in a second car to get it charged before our off-peak time ends.
I agree here with exceptions: Large, inefficient EVs (trucks) charging overnight on the road.
For cars, in general, I agree, however, as trucks start becoming more prevalent, 11 - 20 KW will be much more necessary for hotels and work fleets.
I do agree that, for apartment or workplace charging, many 3 - 6 KW stations will be more valuable than fewer 11 - 20 KW ones, given that most folks don't need to charge for more than a day's car usage so maybe 100 miles of range would be the most normally needed.
Your 2:1 cost ratio is flawed as I and others have pointed out. As far as shared resources go (think hotel), once they run the trench out to the parking lot and install the pedestal, whether they run thick or thin wires is nearly irrelevant.
What I hate is when someone only installs 1 charger when, after installing one, for less than ~1/4 that price extra, they could have installed 2 chargers, and they could have installed a whole lot more for about 1/8 the cost for each additional one.
Think this all you want, however, when I see your hotel charges me an idle fee and the one next door doesn't or rents rooms for cheaper, I'm not going to your hotel where I'll have to get up in the middle of the night (after having to guess or figure out when my car will be done) in order to move it.
The solution is for you to install more chargers because you don't have enough. Getting your knickers in a wad about what current they provide or how they get used won't help your business at all.
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