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Discussion Starter · #1 ·
Nicolas Raimo on YouTube uploaded an interesting video where he suggested that the future of charging should be AC (especially including 11 kWh, 22 kWh, and 44 kWh), not DC fast charging. He makes some interesting points, most especially the fact that AC charge units are drastically cheaper than DC fast chargers, so you can deploy a lot more of them for the same amount of money. A DC charger is an actual charger, an AC charge unit is supplying power to the internal AC charger in the car, and that's one of many factors that makes them cheaper. Obviously many cars are limited to as low as 7 kWh AC charging, but that might change if the priorities of car buyers change.

The more I think about it, the more it makes sense. A massive deployment of destination chargers, rather than a much smaller deployment of DC fast chargers, could be a better future for most people. Imagine plugging in almost everywhere you park (where you live, where you work, every time you stop somewhere to shop, etc.). Paying for the electricity of course, so it would be optional for those who don't need it and prefer to charge only at home.

So often we talk about a future full of DC fast chargers, but they're very expensive, and the people putting them in need to recoup those additional costs by charging users more, and super fast charging isn't ideal for long-term battery service life.

Obviously there would be hurdles to such a future (most especially sorting out billing). But presuming those hurdles could be conquered, what future would you prefer? A future with mostly AC charge units and a few DC chargers for unusual situations, or a future of mostly DC chargers (but far fewer than in the AC charge unit scenario)?

My vote would be for government and/or industry to lead the way in pushing for better AC charging, so that the units can be cheaper to deploy, and that you'd have the option of plugging in almost everywhere you park, with a small number of DC fast chargers (that cost more per kW) that people would mostly only use during inter-city trips.

At some point the growth of electric vehicles will be such that we could see a lot of DC chargers around like in Norway. Or we might instead have a future where the incentive is for every new (or remodelled) parking lot to have AC charge units for a large number of parking spots. I'd much rather the latter.
 

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Interesting that you raise this now as another thread is currently raising issues about DC chargers in the UK

Why do I not feel sorry for them?

In theory DC chargers are more efficient as you pointed out yourself in that the charger is shared rather than each car having to carry such a large charger for a rarely used event of charging at a very high rate. Most UK homes are single phase and limited to to 7kW so it makes less sense to carry a bigger charger than that.

The issue then is how best to allow for journeys beyond the capacity of the battery where planned long breaks to recharge slowly are not available. Too many people still try to use their EVs like ICE and expect to be able to refuel very quickly on demand, hence the petrol head thinking of 350kW DC chargers. I believe that people need to balance their usage such that "fast" AC charging at 7-11kW is sufficient and use alternative means of transport for longer distances. This would be a major change in life styles as even 11kW amounts to only around 35 miles range added each hour, and hence to refill say an ID3 after 200 miles takes 6-9 hours.
Yet again the benefits of the Tesla Supercharger network are shown to replace ICE thinking, but I fear that the UK is too disorganised to replicate it for other brands and all cars.
So as a straight answer, more AC chargers.
 

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That’s kinda what’s happening already.

The flagship sites here have dozens of fast chargers but only two rapids, I’ve seen similar sites with no rapids only AC.

NatWest bank are building a site with 200 AC chargers, no rapids.

One of the many reasons why I’d like to change to a car with a faster on board charger.

Cheers
 

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I think it's not one or the other. It's the combination of both that's important. Rapid Charging is vital, even more so on major routes and service stations. They'll always be reason people need a fast charge.

But overall I think you're right that a lot of focus goes on rapids, they are a lot more interesting, but it's high time (given the coming petrol car ban) that building regulations include AC chargers not just for businesses but for homes.
 

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Renault ZOE R135 ZE50 GTLine July 2020 (Sold: R90 ZE40 i Dynamic Nav June 2017)
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It's a false question: "If you had to choose ...". We don't and engineering and the market won't let it be one or the other.

We need lots of slower chargers so that cars can be charged when they are left stationary for long periods - at home, at work, at a park and ride, on the street etc. AC charge points are just fancy switches and cheap to supply, but the charger is in the car and we don't want lots of cars carrying around large chargers. And if you want a lot of chargers all on at the same time down the same street then each will have to be limited to match the available supply.

But if I'm stopping on a long journey to recharge then I need a fast charger. It can run at 100's of kW - and can be a DC charger which is too large and heavy to consider putting in a car.

Despite the complaints, we are getting close to the point in the UK where I can set ZapMap to only show >50kW DC chargers where I can pay by contactless, do a little planning, and make most journeys without considering other chargers.

Edit: typos only, for clarity.
 

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Renault Zoe ZE50 R135 GT-Line with CCS in Aconite.
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Charging an EV all comes down to the time you have available!
I cannot charge at home so am having to go to a 7 KWh fast charger and leave the car for a couple of hours. Fortunately I can sometimes access a 22 KWh charger, to top up about 50% is done in about an hour. I know everyone isn't lucky enough to charge at 22 Kw, car manufactures seem to be fixated with Rapid charging speeds and assume that most people will charge overnight at home with a 7 Kw charger!
Faster fast chargers would be cheaper to install, so hopefully we would get more of them.
On long journeys people need access to Rapid chargers to make long distance drives viable, in non motorway settings a combination of both, in my opinion, is the way to go.
 

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I suspect quite a lot of EV drivers are like me in so much as most charging is done at home with public charging only happening on occasional long journeys. With that in mind it makes no sense for me to be carrying around a heavy expensive 43kw AC charger all the time when it's probably only going to get used at anything near that rate briefly every 3 months or so. When I do use a public charger I want that to be as quick as possible so I can carry on my journey and DC is much better at that. Even my little ZS will take a 80Kw charge and as cars develop it will be more normal for them to be able to deal with 150 or even 250kw, something that AC can never deliver.
So in answer to the question we need more 7kw destination chargers for those without access to a home charger and more importantly we need a lot more high power DC units.
 

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44kW is a dead standard, and very few cars support 22kW. In the UK at least, even 11kW cars aren't that common because 3-phase is rare at home.
So for a large number of cars, the choice is between 7kW and 50kW, and both are needed as they serve different use-cases. 7kW for anywhere that people typically stop for at least an hour, e.g. retail parks, workplaces, hotels and car parks, and 50kW+ at hubs for mid-journey charging, with plenty of chargers so there's a high chance of availability.
 

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As ever, it's horses for courses. You want to EVSEs to be where the cars are, when the cars need them. So on m'ways that's MSAs or very nearby, and for as little time as possible, if you think of these as simple replacements for petrol pumps.

But if you see these stop-offs as eateries/shopping opportunities, then the time's less critical, so you're able to get a better fit with more ACs at a lower capital & kWh cost.

Then at the opposite end of the car's activities is the overnight sleep, so domestic/lamp-post/whatever is favourite if access permits. If it doesn't permit, then it's back to Rapids for as short a time as poss, but now you want them dotted around in the built-up housing areas, perhaps 2/village, 4/small town, lots round the city inner ring roads, which we're already seeing happen with pubs etc stepping in.
 

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Discussion Starter · #10 ·
I agree with those who say we need both. I don't think anyone's arguing we only need one or the other. It's more a question of how it breaks down between the two, and much of the attention appears to be on the DC fast charging networks. Perhaps more than is ideal? That's a topic for discussion. This discussion. :)

I hadn't considered that a faster on-board AC charger might be larger/heavier. More expensive I expected, but heavier I didn't predict. Thank you for putting that thought in my brain.

I think public charging lots with slow AC charge units is less what we need, and upgrading existing (and future) parking lots to also be charging opportunities is more what we need. The stores with parking lots can turn it into a new revenue stream! I think even 7 kWh charging is plenty fast enough if it's just topping up a city car while you eat/shop.
 

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I agree with those who say we need both. I don't think anyone's arguing we only need one or the other. It's more a question of how it breaks down between the two, and much of the attention appears to be on the DC fast charging networks. Perhaps more than is ideal? That's a topic for discussion. This discussion. :)

I hadn't considered that a faster on-board AC charger might be larger/heavier. More expensive I expected, but heavier I didn't predict. Thank you for putting that thought in my brain.

I think public charging lots with slow AC charge units is less what we need, and upgrading existing (and future) parking lots to also be charging opportunities is more what we need. The stores with parking lots can turn it into a new revenue stream! I think even 7 kWh charging is plenty fast enough if it's just topping up a city car while you eat/shop.
If you look at the size of a typical 50kW rapid, or a Tesla supercharger and think of the challenges of reliably making that smaller and lighter in order to fit under any bonnet, you get an idea of the challenges of having mobile vehicle onboard rapid chargers.
 

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If you look at the size of a typical 50kW rapid, or a Tesla supercharger and think of the challenges of reliably making that smaller and lighter in order to fit under any bonnet, you get an idea of the challenges of having mobile vehicle onboard rapid chargers.
I thought DC charging bypassed the AC charger and the power went straight into the battery! That as I understand it, is how a rapid charger works. Someone would need to check this out?
 

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It's both, but arranged in a balanced charging ecosystem. The critical factor to determine whether you go with AC or DC is time spent in the location. The kWhs - the energy you need to run your car on - are simply a factor of kW (power) and hours (time). kWh = kW x h.
So if you have lots of time, go for low power AC. If you're short on time, go for high power DC.
This is how I like to think of the mix.

137860
 

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If you look at the size of a typical 50kW rapid, or a Tesla supercharger and think of the challenges of reliably making that smaller and lighter in order to fit under any bonnet, you get an idea of the challenges of having mobile vehicle onboard rapid chargers.
The models of Zoe that can AC charge at 43KW use the motor coils as part of the charger circuit. I believe there’s something specific about the design of the motor that allows this, one reason why it’s unusual.
 

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Until we have so many AC charging point that there is no requirement to having the parking as EV only, a large cost of AC charging is the parking space that becomes EV only. Likewise until AC charging point are as common as parking spaces, there is a requirement for many more public AC charging point then are normally used, otherwise a driver can't depend on being able to charge and having to wait all day for someone to come back to their car is not a option.

This results in many public AC charging points costing at least as much per car charged per hour as rapid chargers. As in most locations that people wish to spend time, parking spaces are of great value to the business thst owns them.

Soon (within 5 years) hotels will find business travellers choosing hotels bases on having AC overnight charging, then some hotels will have a high cost to use three, and others will AC charging points in every parking space, like they do with WiFi in every room. I see few companies other then accoundation providers haveing many customers who choose them base on AC charging points.

But any pub/restaurant/gym/supermarket can gain 6 to 8 more customers per day by allowing a rapid charing network use of two parking space as no cost to the pub/restaurant/etc. (This incudes pub/restaurants at hotels.)

Hence I expect to see Rapid chafing networks expanding at many sites people naturally spend about one hour at, and only when EVs become much more common do I expect to see AC charging points being installed on mass.
 

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One instance that I'd like to see more AC destination chargers is in shopping centres etc. In Norwich we have a load of 7kw bays in the Castle Mall which is ideal (partly because they're free!). If these were DC rapids then I wouldn't be able to leave my car charging for several hours whilst shopping / eating however with the 7kw destination chargers that's precisely what we can do.
 

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Renault kind of shot themselves in the foot with 43kW AC charging. The were granted so many patents around the way that they had implemented the charger using the motor coils, it meant that for any other manufacturer to fit 43kW AC charging they would have either had to pay Renault royalties or install large inductors in the car. This resulted in no one else adopting 43kW AC charging with the result that it has died and even Renault have now moved over to DC rapid charging even though there only current model can only DC charge at 43kW!
 

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The models of Zoe that can AC charge at 43KW use the motor coils as part of the charger circuit.
All models of Zoe use the motor coils as part of the charger circuit. That's why the 22kW version can charge at 22kW - it uses all three phases. The 43kW version uses a motor made by Continental, and presumably has beefier circuitry.
 

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Again, both. 7kw is no use if you are making long journeys, and unless you are traveling town centre to town centre alternatives aren’t viable. But if you can’t charge at home, 7kw where your car is likely to spend considerable time anyway is better than having to spend 40 min on a rapid.
 

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Discussion Starter · #20 ·
If you look at the size of a typical 50kW rapid, or a Tesla supercharger and think of the challenges of reliably making that smaller and lighter in order to fit under any bonnet, you get an idea of the challenges of having mobile vehicle onboard rapid chargers.
This is exactly why I didn't expect a beefier AC charger to necessarily be that heavy in a car. A DC charger is an actual charger, an AC charging system is partly in the car and partly what you plug into your car, so I didn't expect it to be nearly that large/heavy. But perhaps it is, I truly do not know. :)
 
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