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Discussion Starter · #1 ·
I can't believe it's just down to cost when a relatively modest EV like a Renault Zoe can charge at 22kW AC. But EV's like Porsche Taycan, Audi E-tron, Merc EQS costing three times as much can only charge at 11kW AC?

It's so much cheaper for a business to install a 22kW AC charge point than a DC Rapid Charger. Surely it would be a good selling point for an EV to be able to charge at 22kW AC?
 

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Kia e-Niro 2 LR, Seat Mii
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Because 22kW is 3 phase. Some homes in France and Germany are 3 phase, but most others worldwide are not, so it would be a waste of money to install the higher powered charger in the car and raise the price for a feature that won't be used.
7kW is enough to charge overnight, and 22kW is not enough for efficient en route rapid charging in a world that is moving from 50kW to 100kW and more.
 

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Zoe uses the motor windings as part of the OBC this keeps the cost down, one version can charge upto 43kW on ac. Its a very clever system.
Fitting 3 7.2kW chargers is much more expensive than 3 3.6kW units so is not done. Also see @Anahata comments
 

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Discussion Starter · #5 ·
I understand the point that 7kW is fast enough for overnight charging and 22kW isn't fast enough for en route charging. But I also see a steady stream of EV's using the 22kW charger at Tesco and none of them apart from a Renault Zoe can charge at more than 11kW. Maybe it's just me? But I regard the ability to charge at 22kW AC a valuable benefit when a DC rapid charger isn't available.
 

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I understand the point that 7kW is fast enough for overnight charging and 22kW isn't fast enough for en route charging. But I also see a steady stream of EV's using the 22kW charger at Tesco and none of them apart from a Renault Zoe can charge at more than 11kW. Maybe it's just me? But I regard the ability to charge at 22kW AC a valuable benefit when a DC rapid charger isn't available.
Yep, it’s a great reversionary mode and more useful for scenarios such as shopping.

With a DC charger you have to worry about coming back to move your car.
 

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My understanding is the Renault system of using the motor windings as inductors in the charging circuit is patented. As @Spiny says it’s a clever solution. Everyone else has stuck to a dedicated 32A charger or effectively a bank of three 16A chargers. Maybe @mikeselectricstuff can comment on charger design.

It may be this is a patent issue and Renault have either refused to license it or others just don’t want to pay. It may also be dependent on the motor Renault use.
 

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22 kW AC is a lagacy standard, its like fast rewind on a video tape, a great feature in its day but not as good as a CD ROM. Don't forget that the car has to lump around three charger with the associated cost weight and complexity. My work put in 22 kW chargers which is a waste as no one wants to move their car during the day so we charge one car per charger that then sits there idle for most of the day.
 

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22 kW AC is a lagacy standard, its like fast rewind on a video tape, a great feature in its day but not as good as a CD ROM. Don't forget that the car has to lump around three charger with the associated cost weight and complexity. My work put in 22 kW chargers which is a waste as no one wants to move their car during the day so we charge one car per charger that then sits there idle for most of the day.
Although 7kW is enough to charge overnight at the moment it’s not going to be soon. It would take about 14hrs to charge a 100kWh battery full to empty and as batteries are getting bigger people aren’t charging little and often as much, but plugging in when ‘low’ to ‘fill up’.

22kW is 4.5hrs on that size of battery so somewhere in the 11-22kW range is probably going to be the right speed for both off-peak (octopus go window) night charging and destination charging.

If I was putting in destination/workplace I would probably consider 22kW capable chargers with some load balancing - if the local grid could take them.
 

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It may be this is a patent issue and Renault have either refused to license it or others just don’t want to pay. It may also be dependent on the motor Renault use.
I understand the drivetrain is built by Continental.

A guy I know put one into a classic car, bought direct from them. It was quite pricey, so probably the reason manufacturers build their own.
 

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22kW is a 32A thee phase supply. That’s all it is. It isn’t a “standard” at all. The standard is the type 2 connector and the comms between the charge point and the car.

22kW is, often, as easy to supply from an AC charge point as 7kW is. It’s just three 7kW phases.
 

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My work put in 22 kW chargers which is a waste as no one wants to move their car during the day so we charge one car per charger that then sits there idle for most of the day.
Yes, workplace chargers and home chargers for overnight use are the two no-brainer cases for 7kW.
Work could have put in 3 times the number of chargers at 7kW with 3 phases equally distributed between them. If you need more than 50kWh to get home from work you live 200 miles away and are in a very small minority.

Although 7kW is enough to charge overnight at the moment it’s not going to be soon. It would take about 14hrs to charge a 100kWh battery full to empty and as batteries are getting bigger people aren’t charging little and often as much, but plugging in when ‘low’ to ‘fill up’.
They'll have to change that behaviour, then. If they are really using that much, it's easier to just plug in routinely every night than to guesstimate whether it's necessary.
I don't think many cars are going to be 100kWh. American pickup trucks, perhaps, but even they are not going to do trips that long every day, or if they are, they'll be stopping at rapids on the way.
 

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You'll see more cars with 11kW 3phase (7kW single phase) going forward, it seems to be a fairly "standard" OBC design now I think it's an option on all the PSA cars and BMW(?) at least. The 22kW on the Zoe used the motor so forces all sorts of design limitations on what you can do drive-train wise for a charging rate that's been superseded by DC charging.
 

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Yes, workplace chargers and home chargers for overnight use are the two no-brainer cases for 7kW.
Work could have put in 3 times the number of chargers at 7kW with 3 phases equally distributed between them. If you need more than 50kWh to get home from work you live 200 miles away and are in a very small minority.


They'll have to change that behaviour, then. If they are really using that much, it's easier to just plug in routinely every night than to guesstimate whether it's necessary.
I don't think many cars are going to be 100kWh. American pickup trucks, perhaps, but even they are not going to do trips that long every day, or if they are, they'll be stopping at rapids on the way.
Not sure I agree, bigger batteries are the big ‘ask’ at the moment because range anxiety is highlighted as the biggest barrier to ev uptake in every review (cars are ready but charging isn’t). Plus as battery technology improves its an easy way to use existing models (new 2023 ID3 with increased range).

Moving to a ‘plug in when you can’ approach is quite an ask too - maybe if chargers are all tethered (no need to lug a heavy cable out of the boot) and free/super cheap but I think we’ll need inductive charging before people really constantly top up.

I’ve seen mobile phone charging used as a potential model for EV charging and if it can be a case of ‘park up plug in’ then brilliant - for cost, grid balancing, etc. I just don’t see it versus people filling their ‘tanks’ when they’re on the red.
 

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It's not the 22kW chargers that get me, it's the 11kW chargers. Why would you fit a 3 phase charger to a car that only allows 50% more power? Especially as 1 phase of that charger has to do 7kW anyway, why not make the other two phases do 7kW.

I get that the bigger the charger the car has to carry around with it, the heavier and more expensive it is. But once you've gone 3 phase, do it right.

For the record, I chose a Zoe ZE50 because it can do both 22kW AC and 50kW DC. DC will become common place, but not in the next 5 years. In the mean time, if there is a 22 but no DC, I can still charge at medium speed. In a Corsa or 208 etc, I'd be stuck at waiting for a 7kW charge.
 

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It's not the 22kW chargers that get me, it's the 11kW chargers. Why would you fit a 3 phase charger to a car that only allows 50% more power? Especially as 1 phase of that charger has to do 7kW anyway, why not make the other two phases do 7kW.

I get that the bigger the charger the car has to carry around with it, the heavier and more expensive it is. But once you've gone 3 phase, do it right.

For the record, I chose a Zoe ZE50 because it can do both 22kW AC and 50kW DC. DC will become common place, but not in the next 5 years. In the mean time, if there is a 22 but no DC, I can still charge at medium speed. In a Corsa or 208 etc, I'd be stuck at waiting for a 7kW charge.
These cars have three 16A single phase chargers, one on each phase to give you the 11kW three phase. Two are ganged together for 7kW single phase charging. Aside from the extra switching required between single and three phase it’s a simple solution and probably the most cost effective way of getting a bit more power on a three phase supply. It’s always a compromise between cost, weight and requirements.
 

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It's not the 22kW chargers that get me, it's the 11kW chargers. Why would you fit a 3 phase charger to a car that only allows 50% more power? Especially as 1 phase of that charger has to do 7kW anyway, why not make the other two phases do 7kW.
They are actually 3 x 3.6 kW, which is 10.8, which is rounded up to 11.
 

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I would love 22kW to be more common. There are plenty of times when I'm parked up for a few hours (and don't particularly want to move) - 50kW would be too fast, and 7kW too slow.

But I appreciate that need is probably not common enough to warrant widespread adoption.

The Zoe's has a trade-off - AIUI, the slower you are charging, the less efficient it is. Granny lead is ~35% lossy, I think. Somebody cleverer than I might be able to explain the details - or indeed that I imagined it!

I agree that home charging at faster than 7kW would be beneficial. Both because of larger battery packs and potentially short cheap charging windows.
 
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