Hi Brad,

Agree on the 50KW chargers to pair with conventional batteries who has a shorter constant charging tolerance.

When the constant charging can be extended, then bigger chargers make sense, especially in the sense manufacturers can install fewer batteries to lower the upfront car costs, or shorten the charging idle times, for the ROA considerations of commercial applications.

If you won’t mind, may I provide you updates about the eXtreme Fast Charging (XFC) development by my team?

Best,
//BJ

People dont want to drive the speed limit on highways that are still at 55mph. They drive at 75mph+ and get mad for you doing 60mph.

I really don't see how you'll convince people to take time out of their day to even charge for 10 minutes when they want to "save" that 2 or 3 minutes driving faster. Especially those who rack on a ton of mileage as is. You dont even have charging stations 99.99% of where you park. Who's going to pay to put them there?

EVs plain and simple are only for the niche market. It's still too far from being able to be reality let alone practical right now. We should be exploring alternative/synthetic fuels for existing combustion engine vehicles which is a more practical and more cost effective method where little needs to be done to make it happen.

The author seems misinformed about level 2 chargers. First off they typically max out at 9,600kw, not 8kw. There are also a few 13,440kw chargers out there with 19,200kw right around the corner. The author calls them expensive and seemingly tries to make them sound like they're not as cost effective as the extremely expensive DC charging but they cost practically nothing compared to what the author is pushing for.

Hell, fast/"faster" charging isn't really all that necessary in the first place. At 9,600kw and using the author's 4mi/1kw you get 38.4mi per hour of charging. Considering that Americans drive an average of 29.2 miles a day you'd only need 46 minutes of charging a day at that rate but since the charging would occur at the halfway point (you still have to return home) you will only be able to recover half the total round trip expended charge when starting out with a full battery. This means 14.6mi and about 23 minutes for the halfway point. Charging at that rate would recover the whole expended charge within the time it takes to eat or go shopping.

Charging is meant to be done primarily at home or wherever else you're staying and almost exclusively on level 2 chargers. Level 2 chargers away from home are meant to slow down the loss of charge while going about your business, while fast/"faster" chargers are only meant for extreme cases for long trips where there's no way to get from point A to point B in a set amount of time without them. Manufacturers (including Tesla) recommend against using anything other than leven 1 or 2 because anything else can seriously degrade the battery over time.

There are a lot of moving parts in the EV arena. While charging speed is a major consideration there are many others that are the bigger fish to fry. I have a 230m range Leaf, and it’s the third Leaf I have owned. Each has been a great car. My home charger is Level 2, 6.6KW.

For EVs to become mainstream, a number of things need to change or be addressed.

A. Many charging stations just don’t work at all. It’s a list of things that go wrong, and so far I see this maybe 40-50% of the time. I got my current Leaf less than a month ago from a distant dealer and had to charge along the route to get home. Two of the four places I stopped didn’t work.

B. Most people know almost nothing about the mechanics of EV charging. Many sales people are not in much better shape.

C. Any kind of real trip is hard, as you can’t risk running out anywhere. It can easily be 75+ miles to the next station. We will need a lot more stations and much closer together.

D. EVs with range in the 200 or so miles are only good for local travel. For any kind of real trip you need something closer to 400 and options for charging in less than 45 min.

E. Every ICE gas pump has pretty much the same nozzle. With EVs, there are at least 4-5 different kinds and most aren't interchangeable.

My Leaf can charge at 100KW, but I have yet to find any stations with anything more than 50KW so far. While faster changing would be good, it’s way more about whether they exist at all and are actually working on a given day.

In Europe, a much more mature EV market, we see lots of 11kW and 22kW stations (AC). All destination chargers on the street, in hotels, at IKEA, etc. At home people usually also install an 11 kW charger.

50-250 kW DC chargers are available but require much(!!) more space and are much more expensive, even the cheap ones. The scenario you paint is only relevant for people that drive extreme distances continuously, so much that they even need that one hour of charging during visiting the grocery store, because they can't charge at home or at work. Or drive crazy distances.

Furthermore the electricity grid may not be able to accommodate quick charging everywhere. In Amsterdam they're already seeing the effects of the higher load on the net and they now have smart charging stations that vary charging speed depending on time of day and available solar power. Sunny day means higher kW (up to 22 kW). Evening peak when people get home from work means lower speeds (3.6 kW)

I'm guessing your scenario is a relatively small number of users. By far the most people will fit the European scenarios. Home charging, destination charging (including at work), and supercharging. Anything else is just an edge case. You can see that this is true in Europe.

Efficiency of the EV is key because it effectively buys you faster charging forever. This needs clever electrical design but above all, excellent aerodynamics. The Tesla Model 3 and Hyundai Ioniq electric are the best examples; all Hyundai-Kia electric cars are proving to be more efficient than the competition. Then even a 50kW charger can deliver a couple of hours driving in ~30 minutes. Or, a single 7kW post at work can charge two cars per day, not just one.

The conclusions of this article lend themselves to support the very reason that I bought a 2018 Mitsubishi Electric Outlander - SUV. For the short term the PHEV is an excellent match for existing infrastructure. My typical urban driving hardly ever exceeds 22km, covered nicely by Home Level-1 overnight, or cheaply installed 2 hour Level-2 charging. If I need the odd occasion to go further, I can use the existing Gas Station network, supplemented by overnight Electric charging at hotels & restaurants. And furture supplemented by 20 minute Chademo Fast charging by the Flo Network, while driving for vacation distances.

We got our Model S 6 years ago and immediately took a 2,000 mile trip to a wedding in Mobile, Alabama then back up north through Mississippi. Very few Superchargers back then. Made several stops at RV parks and did a lot of educating. Not many people knew what an electric car was back then, let alone what to $ to charge us to use a spot for a couple of hours. Generally the RV parks are wooded and in a nice setting so we didn't mind stretching our legs. Now we can go pretty much anywhere in the US we want to go and find a Supercharger for free. We will always choose driving over flying if it is practical and have gone coast to coast. As a result, we have degraded the battery capacity quite a bit. Started with a range of about 268 and can now only charge to around 230 and only count on about 180-190. Last time at a service center, they said we supercharged about 40% over the life of the battery which surprised us since we have a home charger but we only drive 2 miles to work (when we drive) so I guess that makes sense. We will definitely get an EV next car and most likely a Tesla - we love how smooth, quiet and fast the car is.

I think hotels and restaurants need to get onboard ASAP. They could charge a couple of cent premium on the electricity and have a nice flow of ancillary income. In addition, people may seek out those businesses specifically because of the charging capability. It reminds me of some of the convenience store chains who sell their gas considerably cheaper than the competing gas stations because they aren’t in the gas business. They are just using the gas as a way to funnel people into their stores where they actually make all their revenue.

KWH aka kilowatt-hour. Or 8kwh equal to 133 watts divided by 110 volts at 1.2 amps. If you charged your car at 250KW it would turn into a pile of ashes. 250,000 divided by say 220volts at 1136 amps. Articles of lost explanation.

The author makes many interesting points about how people are using chargers. I have a Model 3 (300 mile range), I charge exclusively at home. I use 120v. I plug it in when I get home, and unplug it when I leave. That covers 99% of what I do. For long range trips, I never spend more than 15 minutes at a super charger, I stop, put it on the charger, walk around, use the facilities, and never fill it up 100%. I just make sure there's enough juice to drive another 200 miles, stop at the next super charger, do the same thing.

As a Tesla model 3 long range owner, this article seems rooted in the technology of perhaps 5-10 years ago, when electric cars had fairly short ranges. If you've got 90-120 miles of range, then maybe you'd be interested in all the places there are public chargers. Our experience is that we charge the car 2 maybe 3 times a week, at home, at night while we sleep. Against this backdrop, we have almost no interest in the various public level 2 chargers in our area. When we go on a road trip, then we will use the supercharger network. You stop for 20-30 minutes which will get you back up to about 260 miles of range, and you're good to go. This article assumes that charging stations = gas stations, but if you already had a gas station at home, would you ever stop at one unless on a road trip?

I agree with the thoughtful approach but not the conclusion. 50 kW is too expensive to install for normal businesses, and not fast enough for travel. L2 is perfect for homes and workplaces and can be as low as ~ $400 more per tap compared to L1.

Hi, wow you are the first person that has talked about changing charging current based on load. I live in Southern California and we all have smart meters. I actually have an app that allows me to read my meter. What I have been looking for is a charger that would monitor how much power my solar panels are generating. I want a charger that to send the excess power that my solar panels generate to my car. It is a simple calculation if you know the usage. Are you aware of any chargers that have this feature?

Last night I needed to 'top off' my Tesla to make it to a Supercharger this morning to start a 550 mile trip home. I did it with the 'convenience charger' that comes with every Tesla and most EVs. The hotel only had a 110v GFCI outlet I could reach, so I charged at about 4 mph. I got about 40 miles overnight. Anywhere I go all I need is a 240v dryer plug to use my Tesla charger. Forget the SAE J-1772 Level 2 connector. 240v at 30 amps is 7.2 kW which is good for 30 mph. It will give a complete charge overnight, but a useful increase while dining or shopping.

Not all EV charging is the same. The same with lithium ion batteries. Solid state batteries from BOAO are unlike anything you've seen so far, and fast charging can take as little as 10 minutes, adding 80% towards a full charge.
www.linghangboao.com

Thanks for taking the time to document this, there's a lot of misinformation, hype and misguided expectations around charging. It's taken us 20 years to figure a lot of this out - so far - and communicating it in a headline or sound-bite is leaving a lot of important nuance on the table. I'd love to know what you would put down for the top, maybe five key points?

Thanks,
MPT

Your concern about expense would be better directed toward hydrogen refueling stations, which are mind-bogglingly expensive unless subsidized. And yet, people seem to think that gasoline thinking may be worth it. Winning converts from gas to electric power is hard enough at 150 kW, but of course we also need batteries that can take it and thrive.

Brilliant article and matches a lot of what I started thinking now that I have a full BEV and tried out DCFC. You make a good deal of sense and your facts match a lot of what I was seeing and thinking. I have some evidence that the original J1772 standard proposal actually wanted to include a very low level (20kW) DC capability to the Yazaki connector (much like Tesla did do), but probably time ran out before cars like the i-MiEV and Leaf started coming out. It's too late for that now, but an affordable, easy to implement, lower power (<=50kW) charging station might turn out to be the real key to increased EV adoption. Thank you for your article.

We need to standardize plugs and make charging universal. My ICE car does not care which brand of gas goes in and my EV should not care if the charging stations says Tesla, EV Go, etc. Love my EV and will not go back to ICE but the lack of J1772 high speed charges can be frustrating.

It’s all very well assuming that everyone can simply charge at home, but the reality, especially in countries such as the UK, is that many people have to park on the road and don’t have off-street parking at their home. Governments are banning Petrol vehicles from such and such year, but no one has outlined who will pay for lining every street with chargers and adding them to every parking lot. The middle to lower classes are always forgotten when talking about moving to modern technologies wholesale and those people will be unable to charge at home, so will need 1-2 minute full charges at filling stations.

I think this is overall looking in the your direction. I can attest to the work scenario describe and agree with the conclusions presented.

I own a 40kwh LEAF with a range of around 150 miles and mostly charge at home on 240v Level 2 infrastructure but most nights would be fine at 120v. On the rare occasion I come home late with a depleted battery and need to leave early in the morning I want to have the the faster capacity.

At work there is a single Level 2 EVSE that is free not only for employees but the community at large. It is often available because EV adoption is relatively low at this time but there is another employee who drives a Volt as well as a handful of other vehicle's ranging from Teslas to older Prius plug-ins. As I said the station is often not in use but there are other times when it will have multiple cars parked next to it trying to coordinate charging. This is not easy to do because non of us actually work together or know each other (I have had one conversation with the other employee when we happened to show up at the same time but she work in a building across the street from where I work).

At level 2 if I show up to work with I completely depleted battery I t would take about 6 hours to get to full. however rarely will I show up completely empty and even if I do I mostly would only need to charge enough to get home. this means on a level 2 charger I am usually looking to be plugged in for 1-4 hours. For an 8 hour workday that either means I am sitting at the EVSE longer than needed or coming out at some point in the middle of the day. Occasionally this can coincide with a meal break but not always and it can be a crap shoot trying to guess when a complete stranger will be done charging. So yes this is an award dance with no music and a partner you have never met or can even see most of the time.

From this experience I can attest that it would be far more convenient for multiple people potentially all wanting to charge at the same time who are working for an 8 hour day to have multiple level 1 spaces available. If it is no more expensive to put in level 2 then level 1 fine but in this use case more stations is better than faster charging. Even if I had a longer range EV I still think this would hold because its not about percentage gained but miles gained in an eight hour period from a level 1 vs level 2 EVSE. If 40 Miles can top of or get me home in a 150 Mile LEAF it can can do the same for 400 Mile Tesla. The issue comes from either having a longer commute in which case yes a level 2 (or 1.5) would be appropriate or for people who can't charge at home who are reliant on work charging for more than just their commute. I would define both of these as separate use cases that should be able to be anticipated by an employer based on the geography of their location.

Basically there are workplaces that need level 2 but a lot that would be better of with a greater number of level 1.

For 300-600 mile EVs the real need for high power level 2 (9kw-11kw) is at hotels where it would be common to expect drivers to show up empty and want to leave 1st thing in the morning with a full charge. other locations would be theaters and dine in restaurants where people expect to stay longer than an hour but less than four and are also mostly looking for just a top up or enough to get home. The 24kw-50kw and in some cases up to 150kw is appropriate for restaurants and retail where people routinely park for less than an hour. this should be more along the lines of 50kw-150kw along major freeway corridors where people are pulling off for a quick half hour lunch. Finally at rest stops/truck stops you have gas station style 150kw-400kw with bathrooms and a convenience store. All of these need to be ubiquitous enough so that the one you need at any given time is readily available with out much planning needed. (Signage will be important.)

Basically to fight some theoretical man made global warming, Americans will have to give up the most valuable commodity of all. Their time. No thank you. Either make better electric cars or I'm pushing for gas vehicles. I would be happy with gasoline or natural gas.

The best use case for a level 3 150Kw charger I'd imagine would be as a mobole service, somwhat like AAA, that would have vans that would metup with EVs along a route, and topoff their charge on the spot.

Such a service if reliable enough would allow end of journey or bottleneck top ups, a totally different use model over gas stations.

As an exotic energy source that might wind up cheaper in fleet use than batteries they might use a large capacitor instead of a battery, or a microturbine generator running ammonia.