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The controversy in fast charging for electric vehicles

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With mass production of EV like Tesla Model-S the cost of internal charger will drop too. And there should be no cost difference between a 100A single-phase or a 32A 3-phase charger. Maybe the 3-phase charger is even cheaper because of less ripple and harmonics being produced.
I assume future car may have up to 50kW internal charger. What will happen if autobusses or light trucks (like UPS?) have to be charged too? They will need even higher power! DC makes only sense with local storage-systems where cheap power from low-tarif can be used to charge through high-tarif.

Or I can use my old pack from my roadster to charge my new one. Then the double conversion from AC to DC and back to AC makes no sense.
 
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CHAdeMO is being rolled out in Norway [...] Sweden is also planning a rollout of CHAdeMO chargers.

Sigh. What a waste of money.

3x63A charge spot, the only one that can remotely compete with CHAdeMO (but still CHAdeMO is ~40% more powerful). Even 3x80A is not as powerful and is beyond the spec of the Mennekes plug.

This is incorrect.

too "powerful" for night time charging (where 25A single phase is more than enough).

25 A/230 V single phase isn't enough. Assuming 5% charging losses, recharging an 85 kWh battery would take 16 hours. Three phase charge times: 16 A/230 V: 14 h. 25 A/230 V: 9 h. 16 A/400 V: 8 h.

No one currently have spare 25 A single phase outlets. If I have to install a new circuit anyway, I'd much rather have a 16 A three phase circuit - more power, thinner cables, standard plugs, can buy extension cords anywhere, fits more easily in between the existing circuits.

I don't know why they aren't installing 63 A charge poles, the standard allows it. On the other hand, every single charger listed at the CHAdeMO site is 50 kW or less. I see specifications of max 200 A and max 500 V, but this isn't very interesting, power is what counts. 50 kW / 44 kW = 1.14. A 14% increase at twice the cost or more is a bad deal.

My arguments still stand. At power levels up to approximately 50 kW, CHAdeMO is too expensive because it duplicates equipment. Three phase will do this job just fine at lower cost and with more flexibility. DC charging becomes interesting when the power is approaching 100 kW, but CHAdeMO is too weak and too expensive.

If, despite all this, CHAdeMO chargers are rolled out in significant numbers, then we want support for them in the cars. But that must be in addition to, not instead of, three phase support.
 
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At power levels up to approximately 50 kW, CHAdeMO is tooexpensive because it duplicates equipment. Three phase will do this job just fine at lower cost and with more flexibility. DC charging becomes interesting when the power is approaching 100 kW, but CHAdeMO is too weak and too expensive.

If, despite all this, CHAdeMO chargers are rolled out in significant numbers, then we want support for them in the cars. But that must be in addition to, not instead of, three phase support.

In the US, there are about 250 million cars, compared to about 120,000 gas stations. Fast chargers for covering long distances can probably have an even lower number, since most charging is done with slow and medium speed charging, at home, work, hotels, etc. This means it doesn't make sense to add expensive fast charging equipment to the car while making the plug cheap.

Although the Mennekes plug is defined for up to 44 kW, there is, as far as I know, no electric car existing or announced, which supports AC charging above 7 kW, except for the expensive Roadster with something like 19 kW, and the no-longer built BMW Mini with something like 11 kW (BMW's new electric cars will have less).

I'm sure part of the reason is cost, and even if Mennekes allows 44 kW with an inexpensive plug, that doesn't mean that that car manufacturers will go through the expense of adding expensive chargers to each car to support that maximum. Its more likely that cars supporting Mennekes will go up to only 20 kW, and less than that is even more likely.
 
In the US, there are about 250 million cars, compared to about 120,000 gas stations. Fast chargers for covering long distances can probably have an even lower number, since most charging is done with slow and medium speed charging, at home, work, hotels, etc. This means it doesn't make sense to add expensive fast charging equipment to the car while making the plug cheap.

As I've said so many times, you don't have to add the fast-charging equipment. It's right there - the PEM, the Power Electronics Module, a.k.a the motor drive.

The PEM is a giant water cooled three phase AC/DC rectifier/inverter, perfectly suited to the task of charging the battery with three phase power. That's why it's not only capable of driving the AC motor with power taken from the DC battery, but also charge the DC battery taking AC power from the motor during regeneration. It could just as easily take the AC power from the grid.
 
For Model S, the inverter is now built into a small cylindrical unit directly attached to the motor. Do you still think there will be recharging circuitry in there?
I wonder if the Model S will switch to a completely separate box for charging compared to controlling the motor.
Yes, there is component redundancy for regen and recharging from line current, but there may be good reasons to keep them separate.
 
Why do you insist that CHAdeMO is only 50kW ? Every single charger installed that I have read about is 125A, which at 500V is 62.5kW. At 480V it is 60kW. At Leaf battery voltage, yes, it is less than 50kW.

Our overnight stays are always longer than 8h on roadtrips, more usually about 14h. If I'm down to 15% on the 90kW battery (don't see us taking it much lower) I need to recharge 76.5kW which in 14h is only 24A, so ~25A after losses.

Most every home in Norway, and most of the cabins we rent on roadtrips, have a 25A outlet. They are very common, though sometimes only fused at 20A. They are used for the kitchen stoves (cooktops?). A suitable adapter will let me use that for charging.

At home I'll stick to 16A 230V single phase. That's what's available in the garage already and I don't see us requiring any faster recharging there.

CHAdeMO stations are planned along every major road here, from south to the very north. Substantial goverment grant money is available for this. L2 charging will also be available at every site, probably single phase 16A for the time being.
 
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As I've said so many times, you don't have to add the fast-charging equipment. It's right there - the PEM, the Power Electronics Module, a.k.a the motor drive.

I haven't yet heard a car manufacturer say this. Like TEG says, the regen circuitry may be integrated with other motor electronics and their specifications, and not an accessible self-contained module. It may be possible in theory, perhaps even practical at 44 kW, but since no cars are announced with this feature (not even german ones from the companies officially advocating Mennekes), it would take a certain number of years. Certainly it is at this point too late to make the required changes for the Model S (unless that is already part of the plan, which I very much doubt). However, I could easily imagine 3-phase adapters for lower rates, and that would certainly make sense.
 
As I've said so many times, you don't have to add the fast-charging equipment. It's right there - the PEM, the Power Electronics Module, a.k.a the motor drive.

The PEM is a giant water cooled three phase AC/DC rectifier/inverter, perfectly suited to the task of charging the battery with three phase power. That's why it's not only capable of driving the AC motor with power taken from the DC battery, but also charge the DC battery taking AC power from the motor during regeneration. It could just as easily take the AC power from the grid.

For Model S, the inverter is now built into a small cylindrical unit directly attached to the motor. Do you still think there will be recharging circuitry in there?
I wonder if the Model S will switch to a completely separate box for charging compared to controlling the motor.
Yes, there is component redundancy for regen and recharging from line current, but there may be good reasons to keep them separate.
We don't really know how the Model S is setup, but eledile does have a point. The Roadster supposedly does regen up to 40kW. That's a momentary 40kW of variable frequency 3 phase AC being rectified to DC. With the Model S PEM being water cooled, perhaps it could handle that power continuously at 50 or 60 Hz (rather than as some 1000s of Hz). If Tesla doesn't exploit this capability, we must assume they have their reasons (be they due to engineering or monetary concerns).
 
For Model S, the inverter is now built into a small cylindrical unit directly attached to the motor. Do you still think there will be recharging circuitry in there?

Yes. They have switched to water cooling, that would make it possible to build it much more compactly.

I wonder if the Model S will switch to a completely separate box for charging compared to controlling the motor.
Yes, there is component redundancy for regen and recharging from line current, but there may be good reasons to keep them separate.

That may be, but I would be very interested in knowing what those reasons are. One credible alternative would be that both PEM and charger is sourced from subcontractors, and no-one has thought of coordinating the efforts. Or that the project is in such a hurry that there is no time to do it right. Or there might be technical reasons that I'm unaware of.

I've long since stopped laughing when reading the comic "Dilbert", though sometimes I snigger a little. I am Dilbert, or rather I used to be. I have seen so many disasters caused by bosses stubbornly refusing to admit mistakes, demonstrations of decisiveness by making rash decisions based on faulty assumptions, failures to listen to science-based advice from the guys who actually create the product and just plain boneheadedness. Dilbert is more or less a documentary. I once had a CEO who insisted that we could not buy computers that did not waste our time because we didn't have enough money. Then he convinces the board of directors that it would be a bright idea to buy the smoking ruins of a failed competitor for USD 30 million, borrowed at 16% interest rate, without even getting hold of their products and having our engineers evaluate them beforehand. Their products were utterly useless, they had nothing of value. I saw it coming, so I got another job just before the company went belly up.

And there are so many spectacular failures in the past - e.g. the horrible ATM compromise of 48 byte packet size which is not a power of two, so the packets don't fit in the cache lines of the routing hardware. The list goes on and on.

So when something comes along that I think seems wrong or shortsighted, I will assume that it is, particularly if I try to dig up more information and I can't find anything substantial.

Currently, the Americans insist that their proposal is the best, so do the Japanese and the EU. Neither the Japanese nor the Americans seem to take any notice at all that the European grid is different, they keep insisting that their own solution is perfect, seemingly unaware that the physical grid is wired differently. I've seen similar situations before.
 
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I don't know any details about the Model S charger circuit. I don't know how easily a regen circuit could directly be reused as a general purpose charger circuit.
But I could imagine that it was good practice to put the inverter right next to the motor, but then find it impractical to wire the same for line recharging.

Another possibility is that the inverter could be Tesla custom, but they are trying to use something more "off the shelf" for the charger circuit.
Then of course there could be various patents they need to engineer around.
Maybe the inverter can do regen duty on a partial duty cycle with the liquid cooling running. But can it handle 100% duty cycle (during long charging?) Do you want to have to run the liquid cooling pump the whole time you charge?
Just saying that just because something could serve a dual purpose doesn't always mean it is best to use it that way.
 
We don't really know how the Model S is setup, but eledile does have a point.
Thanks :)
perhaps it could handle that power continuously at 50 or 60 Hz (rather than as some 1000s of Hz).

This is not my field, so please correct me if I'm wrong.

The motor AC frequency depends on motor speed and number of poles, not drive frequency. The drive frequency must be high to be able to smoothly control the voltage, but this corresponds to the fineness of the steps of the AC curve it generates (same as sampling rate). The motor AC frequency varies from zero to maybe a few hundred Hz.

A regenerative drive contains two drives, one to regenerate and one to drive the motor. There is also a rectifier between them. I think they would send the incoming grid power through the rectifier, then feed the resulting DC to the regen half of the drive. The technical term for a regenerative AC motor drive is "four quadrant AC drive".
 
I'm betting all the parts we are talking about are Tesla designed. They are outsourcing things like power steering, AC, brakes, etc. but patent issues (a good point) and costs aside, I believe Tesla is starting with a totally clean sheet of paper.
 
Why do you insist that CHAdeMO is only 50kW ? Every single charger installed that I have read about is 125A, which at 500V is 62.5kW. At 480V it is 60kW. At Leaf battery voltage, yes, it is less than 50kW.

Because rated power is 50 kW. It is very common for electrical equipment to be unable to deliver maximum current and maximum voltage at the same time. Then you have to look at the rated power. If it produced 62.5 kW, they would have written that.

Most every home in Norway, and most of the cabins we rent on roadtrips, have a 25A outlet. They are very common, though sometimes only fused at 20A. They are used for the kitchen stoves (cooktops?). A suitable adapter will let me use that for charging.

I would prefer not to have to move the stove out of the way to steal its outlet and run the cable through an open window, though I'd do it in a pinch. However, as you say, many of these are fused at 20 A, including my own. And what do you do in Denmark or Sweden, when there is a three phase outlet there instead?
 
Because rated power is 50 kW. It is very common for electrical equipment to be unable to deliver maximum current and maximum voltage at the same time. Then you have to look at the rated power. If it produced 62.5 kW, they would have written that.

This DC fast charger has 60 kW, and uses CHAdeMO:
Blink DC Fast Charger Brochure - Page 2

Maximum Output Power : 60 kW Max (Setting Adjustable 30kW - 60 kW)
Maximum Output Current : 200 Amps
Minimum Output Current : 5 Amps
Output Voltage : 200 VDC - 450 VDC
Input Voltage : 208/380/400/480/575 VAC 3-Phase
Frequency : 50/60 Hz
Input Current : 200 Amps at 208 VAC
89 Amps at 480 VAC
74 Amps at 575 VAC
Connector/Cable : Yazaki-CHAdeMO compliant 120A rated

(I replaced special formatting with colons)

Might push the envelope on the cable rating a bit... :)
 
We don't really know how the Model S is setup, but eledile does have a point. ... If Tesla doesn't exploit this capability, we must assume they have their reasons (be they due to engineering or monetary concerns).

You can't assume the circuit topography allows them to do that. After all external three phase power would be coming in on one set of wires, and it goes to the motor on a separate set of wires. It would have to be designed to do that.
 
Because rated power is 50 kW. It is very common for electrical equipment to be unable to deliver maximum current and maximum voltage at the same time. Then you have to look at the rated power. If it produced 62.5 kW, they would have written that.

I would prefer not to have to move the stove out of the way to steal its outlet and run the cable through an open window, though I'd do it in a pinch. However, as you say, many of these are fused at 20 A, including my own. And what do you do in Denmark or Sweden, when there is a three phase outlet there instead?

Ok, so one manucaturer makes a 50kW unit. Larger units do exist and the standard allows up to 200A (100kW).

As for Sweden, I haven't been further into Sweden by car than Gothenburg the last 20 years. Also I haven't driven in Denmark since 1991, so it's a non-issue for me.

BTW, 20A is 4.6kW, which amounts to ~70kWh in 16 hours. Still ok with me in a pinch.
 
As I've said so many times, you don't have to add the fast-charging equipment. It's right there - the PEM, the Power Electronics Module, a.k.a the motor drive.

The PEM is a giant water cooled three phase AC/DC rectifier/inverter, perfectly suited to the task of charging the battery with three phase power. That's why it's not only capable of driving the AC motor with power taken from the DC battery, but also charge the DC battery taking AC power from the motor during regeneration. It could just as easily take the AC power from the grid.

Most cut out diagrams I have seen (and this includes the Leaf, the iMIEV, the Smart ED, Focus EV etc.) show the charging equipment completely separate from the inverter (some even completely on opposite ends of the car). There must be a reason for this.

As for tapping into the regen circuit for charging, I'm not aware any manufacturer does it. I failed to find any manufacturer that has a 44kW onboard charger either (even in a testing fleet). Like Norbert says, you'll be hard pressed to find even 7+kW (with the exception of Tesla). On the other hand, CHAdeMO equipped cars are already hitting consumer hands, so obviously governments would be getting ready to support them first.

The longer the France/Italy vs Germany political bickering continues on IEC 62196, the more CHAdeMO stations will take hold. Say what you will about J1772's lack of support for 3 phase, but it was finalized as a standard in Japan and US rather quickly because the industry was willing to collectively test and adopt it (and no US vs Japan politics over it).
 
As for tapping into the regen circuit for charging, I'm not aware any manufacturer does it.
Well AC Propulsion has their Reductive(tm) charging which at least reuses some of the drive system components. Roadster drivetrain 1.x relies on some ACP patent(s), whereas 2.x does not. Perhaps charging and drive electronics are separate in the Model S in order not to step on those ACP patents. Obviously we're all just speculating here.

It would have to be designed to do that.
For sure. :smile: