AC vs. DC fast charge

[widodh]

Why would a hotel pay for that expensive thing ? They only need to provide this:

http://www.highlite.nl/silver.econt...tors_380v/cee_form_32a_5_pin_wallmount_female

€9.95 + wiring should be cheap enough for most.

And ZCW is shipping 32A single phase boxes with Mennekes for £299:
http://www.zerocarbonworld.org/shop

I don't think a three-phase version would be much more expensive.

3-phase doesn't have to be expensive.

I build my Open EVSE 22kW system at home for about EUR 800,00. Put that into mass production at prices will be even lower.

Kane seems to forget that cars will be parked at destinations for longer periods. I don't want to stop at DC charger to wait for 45 minutes while my car could have recharged in the 4 hours I had a meeting at a location.

Again, DC and AC (even 44kW) will co-exist. And AC hardware is a LOT cheaper then DC since it's only "connecting the dots" instead of doing the AC -> DC conversion.

 

[Kane]

Why would a hotel pay for that expensive thing ? They only need to provide this:

€9.95 + wiring should be cheap enough for most.

And ZCW is shipping 32A single phase boxes with Mennekes for £299:
http://www.zerocarbonworld.org/shop

I don't think a three-phase version would be much more expensive.

ZCW is nice but £299 excluding VAT and P&P. (£370.80) => over €450 for private point without instalation.
230 V, 32 A => 7,36 kW maximum => minimum over €61 / kW

This is slow charging, without autorization interface to sell energy, need EVSE cable and more expensive on board charger 6,6 kW for maybe hundreds of $/€ to utilize it's potential

 

[widodh]

ZCW is nice but £299 excluding VAT and P&P. (£370.80) => over €450 for private point without instalation.
230 V, 32 A => 7,36 kW maximum => minimum over €61 / kW

This is slow charging, without autorization interface to sell energy, need EVSE cable and more expensive on board charger 6,6 kW for maybe hundreds of $/€ to utilize it's potential

Why is 7kW slow?

Have you ever driven an electric car for more then just 30 minutes? 7kW is just fine when the car is parked for a couple of hours. 90% of the time a car is parked (just as a side note).

Even 3kW charging would be sufficient for a lot of people.

EVs also want to be plugged in to to pre-heating of the cabin, battery maintenance, etc, etc. We don't go to a gas station, fill up and come back when we are empty, you simply top-off all the time.

It's true that 7kW is just to slow for charging during your trip, there you want >=50kW, but for 90%, maybe even 95% of the time charging with 3, 7 or 11kW is just fine.

 

[eledille]

When you use one phase, the motor will not rotate at all, so the rotor type is irrelevant. But I guess that when you use it as an inductor for the three phase, you are in fact creating a rotating field inside the motor and the only way you can prevent the rotor to rotate is if you have a wound rotor and you disconnect the wires. In a permanent magnet rotor you have the problem of hold the rotor using the brakes, quite dangerous!! And in an induction motor there will also be a large current inducted in the wires/squirrel cage that will burn them in a short amount of time.

Anyway, I can be wrong so please tell me if you disagree

I disagree :biggrin:

They wouldn't need the inductor for the three phase end. They might need an inductor at the DC end of the rectifier for smoothing, but that will not generate a rotating field.

The point of using an inductor is that it resists current changes. Think of it as a heavy, freewheeling turbine in a water pipe. Pressure corresponds to voltage, flow rate corresponds to current. A pressure pulse in the water will speed the wheel up a bit, a pressure drop will slow it a little, but the flow will be much smoother than it would have been without the wheel. As a result, little current would be induced in the rotor, because induction is proportional to the rate of change of the magnetic field, and the magnetic field is generated by the current and thus equally stable as the current.

*Edit* And now it just struck me that they don't need any extra smoothing of the rectifier output, because this the regen circuit, which obviously must be able to smooth the current without the benefit of the use of the motor as an inductor - that's where the current is normally coming from! I don't have any idea what they would need the motor for, if anything. AC Propulsions' reductive charger would need this, because rectified single phase is much harder to smooth than three phase.

Aside: Keeping a permanent magnet rotor stationary in a rotating field will likely demagnetize it, which would be unfortunate :scared:

I think same or higher prices of charging per kWh of energy.

Price per kWh is interesting, but not all that matters. Unit cost matters a lot. You just showed us that the RWE pole is less than half the cost and can charge two vehicles. You also need to compare outdoor AC cost to outdoor DC cost.

Also, a hotel will probably not put up a whole RWE charge pole. Those are more expensive than necessary in that setting, they are built like a tank to withstand abuse out on the streets. Check out Kevin Sharpe's projects for more realistic costs.

When you arrive at a hotel for a conference, would you prefer to get an 11 kW charge point all to yourself, or park temporarily at the DC charger and then have to leave the meeting to move the car after an hour? 11 kW or certainly 22 kW is enough in this setting. The hotel would be able to serve four customers with less hassle for the same price as the DC charger.

If it's a half-day conference, then you very likely haven't driven all that far to get there, and 11 kW is enough to top your car up. If it's a full day conference, you will get a full charge even if you arrived empty.

This is the only chance for high power AC charging to be in some applications profitable.

Correct. However, each and every EV has a powerful three phase inverter, which as Renault has proved can be reused for charging at multiple single and three phase power levels at exceptionally small cost. This is the way it will be done, and that means that DC charging at less than approximately 70 kW is dead as a dodo in all markets where you can easily get three phase power. I'm all for truly high power DC, but it needs to provide a significant extra punch above 43 kW three phase to be worth the extra cost, I'd say 75 kW as a minimum.

 

[jerry33]

Why is 7kW slow?

It depends on what your goal is:

1. Obviously it's fine for overnight charging.

2. It's not so good if you're on a trip and waiting for it to fill.

3. It's not good if you are in a valet parking garage and the valets are trying to get one car charged so that the next one can also be charged.

Most charging should be done at home except for trips and the odd situation, charging during the day for local driving should almost never even be considered. Charging at work is a non-starter and really shouldn't even be persued. If that isn't the case for you, then you have purchased the wrong EV.

 

[Bipo]

I disagree :biggrin:

They wouldn't need the inductor for the three phase end. They might need an inductor at the DC end of the rectifier for smoothing, but that will not generate a rotating field.

The point of using an inductor is that it resists current changes. Think of it as a heavy, freewheeling turbine in a water pipe. Pressure corresponds to voltage, flow rate corresponds to current. A pressure pulse in the water will speed the wheel up a bit, a pressure drop will slow it a little, but the flow will be much smoother than it would have been without the wheel. As a result, little current would be induced in the rotor, because induction is proportional to the rate of change of the magnetic field, and the magnetic field is generated by the current and thus equally stable as the current.

*Edit* And now it just struck me that they don't need any extra smoothing of the rectifier output, because this the regen circuit, which obviously must be able to smooth the current without the benefit of the use of the motor as an inductor - that's where the current is normally coming from! I don't have any idea what they would need the motor for, if anything. AC Propulsions' reductive charger would need this, because rectified single phase is much harder to smooth than three phase.

Aside: Keeping a permanent magnet rotor stationary in a rotating field will likely demagnetize it, which would be unfortunate :scared:

But if you use a normal three phase six pulse rectifier you don't get full power, but only a third (as you switch between each fase each 60 elec. deg.)

If you want to get the full power available you need three one-phase rectifiers, so you may use a capacitor or an inductor to accumulate energy and get a stable output. There is where the motor wires are used as a powerful inductor.

P.S: The permanent magnet rotor will certainly be spoiled, another fact to preffer the wound one.

Correct. However, each and every EV has a powerful three phase inverter, which as Renault has proved can be reused for charging at multiple single and three phase power levels at exceptionally small cost. This is the way it will be done, and that means that DC charging at less than approximately 70 kW is dead as a dodo in all markets where you can easily get three phase power. I'm all for truly high power DC, but it needs to provide a significant extra punch above 43 kW three phase to be worth the extra cost, I'd say 75 kW as a minimum.

That's exactly what I think about the AC/DC war. DC should be only used for long trips, when you would need to top the battery up as fast as possible.

 

[eledille]

But if you use a normal three phase six pulse rectifier you don't get full power, but only a third (as you switch between each fase each 60 elec. deg.)

If you want to get the full power available you need three one-phase rectifiers, so you may use a capacitor or an inductor to accumulate energy and get a stable output. There is where the motor wires are used as a powerful inductor.

No, three single phase rectifiers will yield exactly the same result as a single three phase rectifier, but with more parts and much higher need for smoothing.

Sometimes they actually build special 6 or 12-phase rectifier transformers because that's cheaper to smooth.

 

[arg]

This discussion of topologies seems to ignore the need for power factor correction, which adds more complexity to the 3-phase input.

But I think all of this is fairly irrelevant. There may well be useful savings available from sharing parts of the drive system with the charge system, but there are then trade-offs to be made against the necessary switching arrangements to reconfigure the circuit: the charger is never going to become zero cost (or anything close).

The current setup of small chargers in the car and DC fast charging stations is driven by the simple logic:

- Any charging scenario has a 'charger' that converts utility power to the right voltage/current to charge the battery:
"AC charging" means the charger is in the car, "DC charging" means the charger is in the EVSE.

- Charger in the car makes sense in scenarios where every car needs a charger (eg. overnight charging) - fewer total chargers
needed than putting one everywhere there's an EVSE on the off-chance a car might want to charge.

- Charger in the EVSE makes sense in scenarios where you need fewer chargers than cars - which only happens
if several cars can use it before the first one needs charging again, ie. fast charging.

It seems unlikely that overnight home charging is going to disappear (since it's so convenient), so there's always going to be some sort of charger in the car. Hence the only debate is whether fast charging might change from having the charger in the charging station (DC) to charger in the car (AC). This only makes sense (by the above logic) if the cost of putting the charger in the car is cheaper than putting it in the charger by a factor of the number of cars that share the fast charge station in a typical charge cycle - for example, if cars need to be fast-charged on average once a day, and a fast charge site is used by 10 cars per day average, then the cost of uprating the in-car charger for fast charging would need to be less than 1/10 of the cost of the one in the charge station. Those numbers are picked out of the air, but they show the drivers of the decision: to make it worth putting the (fast-)charger in the car, that charger needs to be cheap, cars need to use fast-charging frequently, and charge stations need to be used by relatively few cars per day.

It seems to me that the on-board charger is unlikely to be that much cheaper than a static one. On-board does have the advantage that it's an upgrade (we assume that there would be a small on-board charger anyhow), and that some of these tricks using parts of the drivetrain for charging might offer savings. However, there are also disadvantages: the on-board charger needs to care passionately about weight, while the static charger doesn't ; cooling is also more tricky for the on-board charger - both these factors add cost to the on-board charger. Probably ends up being a bit cheaper overall on-board, but not by a large factor.

Frequent use of fast-charging also seems a bit of a reach: fast charging for occasional road-trips makes sense (and can have a fee that makes it worth the while for the charging station provider). Needing to use fast charging on a daily basis makes the EV less convenient than an ICE, and if you are trying to make that argument on the basis of ICE fuel cost, then the fast charger needs to be free or at least very low cost.

The flip side of that is charge station usage rates: there's substantial costs (capital and monthly) in providing the electrical supply to a fast-charging site, so it either needs to be used very frequently or needs to charge a large fee (even if it's free-of-charge, the owner is presumably providing it to attract custom to the sponsoring business (restaurant etc.) so needs it frequently used). So the combination of cars fast-charging very frequently yet individual charge stations seeing little use seems highly unlikely.


All of that makes me think that AC overnight charging and DC fast charging is here to stay - a small change in the cost of on-board chargers just isn't going to affect the overall logic.

 

[eledille]

arg:

We're not discussing the main inverter. *Edit* Or I wasn't, at least. I should have written that explicitly to avoid confusion, I'm sorry about that.

All modern EVs are capable of regenerative braking. The regen circuit takes its power from the motor in the form of 3-phase AC of voltage and frequency comparable to utility power, rectifies it, and regulates the voltage to charge the batteries. Typical power is 20-60 kW. The regen is an integral part of the motor drive, but is still an exact duplicate of an external DC charger. All you need is a contactor to disconnect the motor and connect to the grid instead, plus fix noise and power factor issues. Precision control of the charge algorithm must also be moved from the standard charger to the regen circuit.

Renault has done this and the result is the Chameleon charger, which is standard equipment in the Zoe. It's capable of charging with 43 kW 3-phase AC. It can also use single phase AC of lower power, so it completely replaces the standard charger. If you look at the price of the Zoe, it's evident that the charger can't possibly cost much.

I find this particularly satisfying, as I've been arguing that this is possible (and what consequences it will have) for years, long before anyone knew what Renault was up to To be honest, I didn't think of it first, a bright electrical engineer pointed it out to me long ago.

 

[Bipo]

No, three single phase rectifiers will yield exactly the same result as a single three phase rectifier, but with more parts and much higher need for smoothing.

Sometimes they actually build special 6 or 12-phase rectifier transformers because that's cheaper to smooth.

I can be wrong, but I cannot understand how a pulse rectifier (which switches between each phase) can deliver the same power of three one-phase rectifiers that are continuosly getting power from the grid.

Here is a graphic that I made to explain what I mean:

IMO if you want to get full power you need three independent one-phase rectifiers.

 

[eledille]

Bipo: It isn't switching between the phases. "N-pulse rectifier" is also misleading, it should be n-phase or n-wave, because they are not discontinuous pulses but sinusoidal waves and continuous to the n'th derivative, phase shifted 2/n π to each other (i.e. they share the unit circle equally between them).

The beauty of three phase AC is that for any of the three phases, at any given time, the sum of the two other phases exactly match its voltage but with the opposite polarity. Thus, no return wire is necessary. This is only true if the load is balanced, and is why balanced loads are desirable. At all times, they act as perfect sources and sinks for each other, so power flows smoothly between them all the time, with no current on the neutral wire (in an IT network, the neutral doesn't even exist). This is why a three phase connection requires less copper than single phase connections of identical total power. Take a look at this graphic.

The second, fifth and sixth of your plots above are correct. The first one is wrong, and I don't know what number three and four represent. In the first one, there should be no white below the curves - the six-diode three phase bridge simply turns the negative parts of the cycles positive. More on rectifiers here.

This is a matter of physics, not opinion :wink:

 

[Bipo]

The beauty of three phase AC is that for any of the three phases, at any given time, the sum of the two other phases exactly match its voltage but with the opposite polarity. This is only true if the load is balanced, and is why balanced loads are desirable. At all times, they act as perfect sources and sinks for each other, so power flows smoothly between them all the time, with no current on the neutral wire (in an IT network, the neutral doesn't even exist). This is why a three phase connection requires less copper than single phase connections of identical total power. Take a look at this graphic.

This is a matter of physics, not opinion :wink:

Yes, I've checked some books and you are correct. My mistake.

I aasumed wrongly that the voltage in the first and second plots was the same of the next ones, but in fact it's SqRoot(3) times it (because of the three phase wires arrangement). So doing some numbers it results that the three phase rectifier extracts all the available power, but it does so at a higher voltage.

If the phase voltage is 230 V, the line voltage is SqRoot(3)*230V = 400V. But these are RMS values, not peak ones. The peak voltage is SqRoot(2) times it: SqRoot(2)*400V = 566V

Then the rectified DC voltage output from the 6-phase rectifier would be between cos(Pi/6)*566V and 566V, so the average voltage would be close to 0.955 times it: 0.955*566V = 540 V.

Thank you for letting me know I was wrong :wink:

 

[arg]

All modern EVs are capable of regenerative braking. The regen circuit takes its power from the motor in the form of 3-phase AC of voltage and frequency comparable to utility power, rectifies it, and regulates the voltage to charge the batteries. Typical power is 20-60 kW. The regen is an integral part of the motor drive, but is still an exact duplicate of an external DC charger. All you need is a contactor to disconnect the motor and connect to the grid instead, plus fix noise and power factor issues. Precision control of the charge algorithm must also be moved from the standard charger to the regen circuit.

Except that the output of the motor doesn't look that much like utility power. Frequency will typically be quite a bit higher. Depending on the type of motor, the output may not be sinusoidal (I can't find detail of the exact type of motor Renault are using: many permanent-magnet motors are wound to give trapezoidal voltage waveforms). Power-factor/harmonics correction also isn't so important for the regen case, wheras it's needed for the external power input.

Renault has done this and the result is the Chameleon charger, which is standard equipment in the Zoe. It's capable of charging with 43 kW 3-phase AC. It can also use single phase AC of lower power, so it replaces the standard charger. If you look at the price of the Zoe, it's evident that the charger can't possibly cost much.

They obviously claim that the Chameleon charger is better than conventional chargers, but it's hard to say by how much. The slide earlier in this thread is obviously nonsense: it claims a cost of EUR 150 for the car side of either AC or DC charging - ie. it's the cost of the high-current connector and wiring (which it's reasonable to say are comparable cost for either). So it's assuming zero cost for the Chameleon charger which can't be right - at a minimum it's got to provide some degree of switching or isolation between the motor and the external AC input. Conversely, the claim a price for external DC chargers that is so high you would be better off buying Zoes and cutting them up to make a charger! More likely those charger costs include other things besides the raw charger (vandal-proofing, payment/authorization systems etc.).

Just possibly, Renault's particular combination of motor choice and electronics design is such that - for them - the incremental cost of adding 43kW of on-board charging is the necessary 10x (or so) cheaper than a stand-alone charger. I think this unlikely, but I can't prove it isn't true.

More likely in my opinion is that Renault have decided that the cost is sufficiently low that it just doesn't matter and they roll it in for political reasons. As noted by someone else earlier in this thread, Tesla's retailprice for upgrading to this amount of charging is $1500 * 3 = $4500. But that is a price for an option that they aren't particularly worried to make cheap: it's probably got a huge amount of margin in it. Maybe the true cost is more like $1000. Renault may well have decided that they need to subsidise fast charging to make the overall business work, and they'd prefer to make that subsidy in the form of free equipment in their own vehicles rather than making cash subsidies to charging station providers which then benefit competing manufacturers.

It would certainly be interesting to know exactly what the Chameleon technology does, but I don't think we are going to get there by guessing at how they've done it - there are too many unknowns. Has anyone identified which patents we are talking about?

 

[eledille]

Thank you for letting me know I was wrong :wink:

It does take some hard thinking to grasp :smile:

 

[eledille]

Except that the output of the motor doesn't look that much like utility power. Frequency will typically be quite a bit higher. Depending on the type of motor, the output may not be sinusoidal (I can't find detail of the exact type of motor Renault are using: many permanent-magnet motors are wound to give trapezoidal voltage waveforms).

Frequency for a four-pole motor at 1500 rpm is 50 Hz. This is a frequency/speed that the regen must be able to handle, and is the same as the utility frequency. Non-sinusoidal motor output only means that the motor is a dirtier source and thus more difficult to handle than utility power. I don't think that creates any extra cost to handle cleaner power. Renault is using a wound-rotor synchronous motor.

Power-factor/harmonics correction also isn't so important for the regen case, wheras it's needed for the external power input.

Poor power factor will make the system less efficient, so that's important for regen also, even if not strictly required. Noise must be handled though, you can make as much noise as you want on your own private network (except for RF emissions of course).

They obviously claim that the Chameleon charger is better than conventional chargers, but it's hard to say by how much. The slide earlier in this thread is obviously nonsense: it claims a cost of EUR 150 for the car side of either AC or DC charging - ie. it's the cost of the high-current connector and wiring (which it's reasonable to say are comparable cost for either). So it's assuming zero cost for the Chameleon charger which can't be right

No, you're forgetting the cost of the DC charger connector - I took this to mean that the Chameleon charger is 150 euro more expensive than the required equipment for slow AC charging plus the DC charging connector/communications/switching gear. These are certainly the two alternatives that should be compared!

Conversely, the claim a price for external DC chargers that is so high you would be better off buying Zoes and cutting them up to make a charger! More likely those charger costs include other things besides the raw charger (vandal-proofing, payment/authorization systems etc.).

But those are entirely necessary costs! You don't need to vandal-proof the onboard charger, and that is a real advantage. Of course, the vandal-proofing and payment system may be equally necessary for the 3-phase AC charge pole, and the costs of the charge poles and DC chargers should be compared. But in a wide variety of situations, you can get away with a much less ruggedized AC system, because you can put them up pretty much anywhere including places that vandals can't get to, and as they are smaller, an AC system is simpler and cheaper to vandal-proof (and weather proof, for that matter). The DC charger is more likely to be public due to its higher cost. Also, as I wrote earlier, unit cost matters tremendously to families, apartment complexes and owners of small businesses. Many of those will not require a payment system either. If unit cost can be lowered whereever only medium (11 kW) or medium-high (22 kW) power is needed, we will get a much denser grid of charge points.

It would certainly be interesting to know exactly what the Chameleon technology does, but I don't think we are going to get there by guessing at how they've done it - there are too many unknowns. Has anyone identified which patents we are talking about?

That would be interesting.

 

[Kane]

Why is 7kW slow?

Have you ever driven an electric car for more then just 30 minutes? 7kW is just fine when the car is parked for a couple of hours. 90% of the time a car is parked (just as a side note).

Even 3kW charging would be sufficient for a lot of people.

Don't understand me wrong. 7 kW is slow not because I don't like it, only because that is the classification (under 11 kW is normal/slow charging, about 22 kW is semi-fast charging, 43-50 kW is fast charging level and maybe 100 kW we should name rapid charging or stay with fast charging).

Personaly I like about 3 kW 1-phase on-board for now. As an option I would consider 3-phase 11 kW in Europe (but only as an option for premium buyers or for cars with bigger battery packs). Tesla luxury cars can have 10-20 kW on-board and it's ok.

arg thank You for joining this topic. Great two posts from You.

If we all agree that about 90-95% of charging situation will be at home then when will be the last 5-10%? It will be when You need to travel far or driving much in one day in city. In this situations You need fast charging, and it will cost You few times more then home charging (no matter AC or DC). So You will use public fast charging only when need it baddly - once a week, or even once a month for average.
As arg said, stationary DC can work for many cars - for example 10 a day (10x 30 minutes = 5 hours of work) or 70 a week or 280 a month. AC on borad will be used on full blast only 1 time per week/month (often use isn't good because cost per km is comparable with ICE). So DC have much more potential to be useful, profitable and finally ofers more power 50-100-120 kW (Tesla). AC on board must be many many times cheaper to be competitive at all and I don't belive it is.
If DC 50 kW cost $20k and AC 43 kW only $10k You have $10k less spend for operator. $10k difference / 70 Zoe = $142 per car on AC reductive charging system implementation, but only Zoe can use it as fast charge.

Another thing. If You even have super cheap AC 43 kW on board and normaly 90% times charge at home 3-5 kW. The power modules in the inverter will work on about 10% of its capabilities (even less because they are rated at 65 kW peak - so about 5-8%). You also have some additional switching arrangements to reconfigure the circuit. If this drive down overall efficiency on charging, driving and regen breaking by just 1%, then after 100 000 km and 15 kWh/100 km and €0,1/kWh You will lose additional €75 alone on efficiency. €75 x 70 cars = €5250. What will be the benefit if people on average will use AC fast charging once per 2 weeks? €75 x 140 cars = €10500 losses on energy in few years compared to DC that will handle 140 cars per 2 weeks?
Look on Brusa top level OEM 22 kW 3-phase charger - how much efficiency going down when working on low power
http://www.brusa.biz/uploads/media/BRUSA_NLG6_Datasheet_EN.pdf
At use on 1-phase they lose about 4% only on charging efficiency (over 90% vs over 94%). And when you using only few kW for example less then 50% on its 1-phase capabilities, or less then 50% on 3-phase (less then 11 kW) it's going even worse. Zoe have power modules 3x stronger then Brusa (65 kW vs. 22 kW) so I assume that usage will be constantly much lower then optimum and efficiency will drop. How much? I don't know.

Small battery charger 3,3 kW is about 93% efficiency.
http://www.brusa.biz/uploads/tx_userbrusaproducts/BRUSA_NLG513_datasheetV02_03.pdf

For me AC 43 kW fast charge public points is very bad solution.

 

[eledille]

If we all agree that about 90-95% of charging situation will be at home then when will be the last 5-10%?

I don't. How many Europeans live in apartments without private parking?

Also, when you drive, do you usually drive around for a while and then drive back home, or do you drive because you're going somewhere? If you shop for an hour, you would get 50 km range during that time if an 11 kW charge point was available. If you park for five hours while you take the kids to the zoo, you would get 250 km of range.

Why you prefer to first go to the zoo, then stop in the middle of nowhere for an hour while charging, trying to keep the children from going bananas in the car during the wait is a mystery to me.

It will be when You need to travel far or driving much in one day in city. In this situations You need fast charging, and it will cost You few times more then home charging (no matter AC or DC). So You will use public fast charging only when need it baddly - once a week, or even once a month for average.

By excluding destination charging you are effectively halving your range. Then you try to compensate by introducing DC chargers.

Even just 11 kW at the destination will almost always allow you to replace the energy you spent to get there. This is a completely painless way to charge EVs - there's this saying that "I never spent any time charging until I started quickcharging"...

As arg said, stationary DC can work for many cars - for example 10 a day (10x 30 minutes = 5 hours of work) or 70 a week or 280 a month.

Only if you're willing to wait while charging, and often queue too. This will get old very quickly, I guarantee it.

AC on board must be many many times cheaper to be competitive at all and I don't belive it is.

This is practically the same as accusing Renault of lying, and you're not backing it up with rational arguments and data. So far all the data points to an extremely low cost. Here's another data point: Renault owns almost half of Nissan, and Nissan owns a substantial part of Renault. Why would Renault reject and even undermine their partner's DC technology if AC doesn't provide substantial benefits? That would make no sense at all.

If DC 50 kW cost $20k and AC 43 kW only $10k You have $10k less spend for operator. $10k difference / 70 Zoe = $142 per car on AC reductive charging system implementation, but only Zoe can use it as fast charge.

You're ignoring that widodh just told you he spent 800 euro on his system, and that I have pointed out repeatedly that AC makes much cheaper 11 and 22 kW charge points possible. Also, Renault has stated that they're more than willing to work with other manufacturers.

I assume that usage will be constantly much lower then optimum and efficiency will drop. How much? I don't know.

This might be a valid point. I don't know the efficiency numbers of the Renault charger. But I'm not convinced that efficiency will necessarily drop at low power - this does for example not happen with the motor drive, electric motors and drives excel at partial load. So far, what I know is that Renault has specifically highlighted their charger's ability to charge at multiple power levels, and I highly doubt they would have done that if efficiency is awful at lower power.

 

[Kane]

I don't. How many Europeans live in apartments without private parking?

Over 50% for sure. Check Eurostat data.

Also, when you drive, do you usually drive around for a while and then drive back home, or do you drive because you're going somewhere? If you shop for an hour, you would get 50 km range during that time if an 11 kW charge point was available. If you park for five hours while you take the kids to the zoo, you would get 250 km of range.

Why you prefer to first go to the zoo, then stop in the middle of nowhere for an hour while charging, trying to keep the children from going bananas in the car during the wait is a mystery to me.

By excluding destination charging you are effectively halving your range. Then you try to compensate by introducing DC chargers.

Even just 11 kW at the destination will almost always allow you to replace the energy you spent to get there. This is a completely painless way to charge EVs - there's this saying that "I never spent any time charging until I started quickcharging"...

I just don't see the need of charging when going to shop, to work, to zoo because all this thing are in 50 km range. Maybe sometimes I will plug-in if AC point is free, but for sure not if price will be like it is (2-3-4 times higher then in home). Anyway - 3.3 kWh in an hour is about 20 km of range when not driving fast (15 kWh/100km). I don't need more. But when I need more I want to have 50 kW option.

Only if you're willing to wait while charging, and often queue too. This will get old very quickly, I guarantee it.

forklifts have DC fast and it can be done to withstand normal operation many years.

This is practically the same as accusing Renault of lying, and you're not backing it up with rational arguments and data. So far all the data points to an extremely low cost. Here's another data point: Renault owns almost half of Nissan, and Nissan owns a substantial part of Renault. Why would Renault reject and even undermine their partner's DC technology if AC doesn't provide substantial benefits? That would make no sense at all.

I don't know. But for me this is strange.
- not using DC from Nissan,
- not using Type 2 terminals in France only Type 3,
- almost every car with different charging philosophy (Fluence Z.E., Kangoo Z.E., Twizy, Zoe).

You're ignoring that widodh just told you he spent 800 euro on his system, and that I have pointed out repeatedly that AC makes much cheaper 11 and 22 kW charge points possible. Also, Renault has stated that they're more than willing to work with other manufacturers.

Maybe widodh will also build cheaper DC and difference will drop again? Less capital cost = more important are utillity costs (better for DC).

This might be a valid point. I don't know the efficiency numbers of the Renault charger. But I'm not convinced that efficiency will necessarily drop at low power - this does for example not happen with the motor drive, electric motors and drives excel at partial load. So far, what I know is that Renault has specifically highlighted their charger's ability to charge at multiple power levels, and I highly doubt they would have done that if efficiency is awful at lower power.

Efficiency drop with partial load not happen with the motor drive? OMG. No comment.
I bid that charging at home about 3-5 kW 1-phase or 11 kW 3-phase with inverter rated on 65 kW will drop efficiency by even 3-5%.

 

[widodh]

On my mobile, so short reply.

Zoo, themepark, etc within 50km? Make it at least 150km.

Destination charging with 3-phase 16A (11kW) makes a lot of Sense!

The 'Efteling' (themepark in NL) recently started to offer charge points.

You'll be in a themepark or Zoo for a couple of hours, with 11kW you can fill up a lot.

I only see a case for DC if and when it is really high power and I want to drive beyond the range of my battery in a single trip.

 

[Johan]

Eledille says "DC charging will get old quickly". He doesn't mean the battery will age, he means you will soon get bored of standing/sitting around waiting for even a 15-30 min fast charge as opposed to plugging in at home or at your destination and then instantly walking away from the car. I agree 100%.