Electric car w/ 20kW inductive charging (no cables! you park over it!)

[Zzzz...]

A vehicle will never get closer than about 4-5" from an inductive loop in the ground.

I'm not sure this is true. What is wrong with springed loop that car push down when drive over it? But!!! Ok. Lets assume you are correct. There are absolutely nothing wrong with "nose" design. And we could position inductive loops as close as we wish. So this is not a problem at all.

Won't be high powered. More power -> bigger inductive loops.

It is high power! It is 3kW charger. More than enough for absolute majority of chargings. Avr person drive around 12k miles a year. Lets assume car drives home only 300 times a year. That leave us with 40 miles charging on average per charging. 3kW for 10 hours would add 30 kWh. Heavy and less efficient than S Model X lets assume would require 400 Wh/mile. Notice all very conservative estimates. So MX would recharge for ~75 miles. More than average 40 miles needed. In reality with 3kW wireless charger person in Model X would go for months and months without need to plugin.

And the best part: coil radius is less than 2 inches! Not much metal there. And it already shown to have overall efficiency of 95%.

And the guys who did it did not had multimillion R&D budget. Sure with a little bit of $$$ invested higher efficiencies would be easily achievable. There are talks about 97% for example. And even that is not a ceiling. The wireless charging should be compared with wired, and wired have got it own losses. With integration of wireless subsystem some of those losses could be avoided. Why Not A Wire? The case for wireless power - Wireless Power Consortium

It is an emerging tech. And a lot should be invested into developing of the tech. But even as is wireless charging is very much comparable to wired one in terms of efficiency. Do not forget - that Toshiba device is tiny! Making it 95% efficient was a hard task. With moving to 2 inch automotive coils gaining efficiency is much easier. And there are talks about wireless charging being as efficient as wired one...

 

[green1]

If your inductive charge plate can be in contact with the vehicle anyway, why not make it conductive terminals instead and save a whole lot of weight, money, complexity, and efficiency?

I see a demand for automated charging solutions, I don't see any good reason they should be inductive.

 

[Johan]

I just came off using an inductive charger for my iPhone. Back to the cable now. An EV is like a phone in that you charge at night and it's impoertant to be done with the charge in the morning. I found wireless to be slower and several times had failed at night due to positioning issues. It gave more trouble than benefit. Plus with a car I'd use more time getting it lined up than I do plugging in and out.

 

[woof]

A vehicle will never get closer than about 4-5" from an inductive loop in the ground.

A vehicle may not, but the coil it uses to match the one in the ground could be lowered to actually touch the ground once the car is parked.

 

[WarpedOne]

A vehicle may not, but the coil it uses to match the one in the ground could be lowered to actually touch the ground once the car is parked.

Or the coils on the ground could raise to close up the gap. It is better to have mechanisms off the car and put just the bare minimum on the car itself.

Why is this better? It still does not need a perfect low resistance contact and no high voltage contacts that really need to be perfectly aligned to match.

I see ludistic resistance to idea. Progress will squash it. I have my $5k reserved for WiCh already.

I found wireless to be slower and several times had failed at night due to positioning issues.

Implementation problems, not "impossible to solve" problems.
As I see it WiCh when done right should be less prone to error than conductive charging - there is one less part where things need be perfect - contact patch, wires flexing and braking.

How many of you having EVs have already drove over charging wire laying on the floor?
What/prevents from this? That human that sooner or later will make a mistake.

 

[hiroshiy]

Inductive charging will find some place anyway. For example there are already some public tests going on with EV bus and wireless inductive charging at the bus stops and garage. The bus charges at the garage while drivers change, and at some bus stops with equipment.

Some Japanese home EV owners complained that their hands got dirty when touching the cable. Especially ladies. They might like the idea of wireless charging.

 

[TonyWilliams]

??? Wait WHAT???...

If electricity is problem, much more effective solution would be to give up performance sedans like T
As for your pathetic hydrogen remark, going gas station(filling station) is absolutely backwards of what wireless charging represents. One waste time instead of saving it. But you know that. You are trying to misrepresent mine words with totally ridiculous idea. Pathetic.

Anyhow, adding couple solar panels to the roof will more than cover for any losses from wireless charging...

Well, that took an awkward turn. I believe you're arguing "for" wireless, and the power inefficiency, expense, weight and cost are not a factor, correct?

 

[Zzzz...]

Well, that took an awkward turn. I believe you're arguing "for" wireless, and the power inefficiency, expense, weight and cost are not a factor, correct?

5% loss of energy would not be a big deal, in case of Model S we go from 330Wh/mile to 347Wh/mile energy consumption. Weight, well in the link above coil/loop used was 10cm in diameter(2 inches radius). Weight is a rounding error. Not sure about cost/expense. But if mass produced cost should not be over couple hundreds USD.

If it would add to convenience, wireless charging will be popular.

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PS. Comparing wireless charging to hydrogen is ridiculous. With hydrogen one would need to visit filling station. One would lose much more then 5%, last time I checked electrolysis was plenty inefficient, and leading industrial sources for hydrogen was coal and natural gas. Add inefficiencies of converting hydrogen back to electricity. Add highly combustible and flammable nature of hydrogen on top(as opposite to batteries). Suggesting hydrogen was way more awkward turn.

 

[rabar10]

While there are clear benefits to hands-free wireless charging (never forgetting to plug in, no touching the car or a charging cable, etc.), we cannot dismiss out-of-hand the added complexity, expense, loss of efficiency (and need to dissipate excess heat), etc. of such a solution.

Hopefully we can all agree that the farther apart the inductive coils are, the less efficient the system is and the less power will be able to be passed through that air-gap. Given that assumption, one of the goals will be to minimize this distance.
- Using moving parts on either the car or the parking spot would seem to add too much cost/complexity except for fleet vehicles or buses.
- A raised bump in a parking spot could work, but I hope the adjustable suspension is set at the right level and that none of the tires are low...
- Putting the coils in the nose or tail of the car so that pulling or backing in would place them together seems a bit dangerous and inviting of bumper-scratches or worse, unless the car is able to autonomously pull to within a few millimeters of the coil for you.

Also, some of the posts here are borderline snippiness material -- please refrain from personal attacks. Thanks.

 

[Larry Chanin]

Not sure about cost/expense. But if mass produced cost should not be over couple hundreds USD.

You'll be happy to know that there is a low capacity system that is currently available for LEAFs, VOLTs and ELRs.

It costs $2,470.

Larry

 

[MartinAustin]

FYI

Formula E gets wireless-charging BMW i8 safety car [w/video] - Autoblog

The i8 and i3 can have inductive charging features, if you believe what they're saying here. It's not stated explicitly but I sense the feeling that they're all-electric car, not just the gasoline-helped normal i8. Maybe they are just brushing that under the carpet... can't see the point of inductive charging on such a teeny battery and in a hybrid car that has a gas tank for longer range. There are lots of hybrid cars out there... charging their tiny batteries inductively would not be a revolution.

But, I guess Qualcomm sees the BMW cars as a platform for getting eyeballs onto its inductive charging system. (which is the exact system used by the racing car in my original post)

Perhaps Qualcomm is serious about getting into inductive charging on electric cars.

"the final specification of car set to be announced shortly" - there is no information here about charging speed or efficiency.

 

[Zzzz...]

You'll be happy to know that there is a low capacity system that is currently available for LEAFs, VOLTs and ELRs.

It costs $2,470.

Larry

Yes, pricing such option at around Studio Sound Package price would make sense for Tesla. But $2500 have little to do with mass production cost. Well, one could buy parking sensors for $20 for set of 4, retail. amazon.com , alibaba.com. Parking sensor hardware probably cost less than $20 for Tesla, yet Tesla charges $500 for it. But again 2500 sounds like a good price for wireless charging option. It just have very little to do with cost of mass producing of hardware.

Besides, pluglesspower.com probably got a very low volume production. If Tesla will come up with such option, takeaway rate at $2500 would probably be well over 10% of ordered MS and MX...

 

[rabar10]

You'll be happy to know that there is a low capacity system that is currently available for LEAFs, VOLTs and ELRs.

It costs $2,470.

Larry

Thanks for the link! Their site links to a PDF with DOE Idaho Lab test measurements of this unit -- which is great to put some actual data and numbers to this discussion.

Specifications:
System Input Voltage operating Voltage 208 to 240 VAC, Circuit Breaker Rating 30 A, Nominal gap between coils 100 mm, Rated maximum power output 3300 watts

Parking Pad (Primary Coil system):
Shape Approximately Circular, Size 559 dia. x 470 long mm

Vehicle Adapter (Secondary Coil system):
Shape Rectangular, Size 464 long x 525 wide mm

Measured System Parameters during Laboratory Testing:
Input Power Measurements (at 3.3 kW output, 100mm gap), Input Voltage 208 VAC, Input Current RMS 28 Amps RMS, Power Factor 0.65, Voltage Total Harmonic Distortion (THD) 4 %, Current Total Harmonic Distortion (THD) 112 %

Wireless Power Transfer Operation:
Operating Frequency (kHz) 19.5 kHz, DC Output Measurements (at 3.3 kW output, 100mm gap), Output Voltage 214 VDC, Output Current 15.4 Amps, Voltage Ripple Factor 0.75 %

Operating Temperatures at 3.3 kW output:
Parking Pad: Max observed surface temperature 51C, Vehicle Adapter: Max observed surface temperature 47C

Efficiency Results (at 3.3 kW output with 100mm gap):
Maximum Efficiency (%) 88.8%, Nominal Efficiency (%) 87.0%, Minimum Efficiency (%) 86.1%

Frankly I'm impressed with the overall efficiency numbers given the 4-inch air-gap. Also of interest is that the output sent to the vehicle charger is DC -- they don't bother to convert it back to AC, and the vehicle chargers seem to be fine with this.

But this is far from a 20kW system -- it's 3.3kW delivered to the car, using 3.8kW pulled from the wall, for 500 watts of losses that will heat up your garage and the underside of the car, where the receiver unit mounts.

Assuming the same 87% efficiency could be realized for a 20kW system, that leaves 3kW of waste heat -- more than can be dissipated passively i.e. now you need fans to cool the unit. There are also safety concerns with the electromagnetic field generated by a 20kW unit -- this PDF shows EM field strengths in the vicinity of this 3.3kW unit. (The company says that their unit detects metallic materials between the two coils and disables power transmission in that case, but this PDF doesn't state that their lab specifically tested that.)

 

[Larry Chanin]

Yes, pricing such option at around Studio Sound Package price would make sense for Tesla. But $2500 have little to do with mass production cost. Well, one could buy parking sensors for $20 for set of 4, retail. amazon.com , alibaba.com. Parking sensor hardware probably cost less than $20 for Tesla, yet Tesla charges $500 for it. But again 2500 sounds like a good price for wireless charging option. It just have very little to do with cost of mass producing of hardware.

Besides, pluglesspower.com probably got a very low volume production. If Tesla will come up with such option, takeaway rate at $2500 would probably be well over 10% of ordered MS and MX...

I appreciate your enthusiasm, but there is a very fundamental reason why pluglesspower is producting in low volumes...there's very little demand for this product.

You can't assume that mass production will reduce the costs when this is inherently a niche market.

As I stated earlier, I personally believe that wireless charging will eventually become a major factor in EV adoption, but only the wireless dynamic charging version while the car is in motion. I see this stationary version to fill the needs of a very small percentage of EV owners and it is therefore unrealistic to suggest that it can ever be priced lower than conductive chargers for the same capacity.

Larry

 

[Zzzz...]

But this is far from a 20kW system -- it's 3.3kW delivered to the car

But 3kW charging should be more than enough for 90%++ rechargings. On average US car drives less than 40 miles per day. 90% of all driving is less than 70 miles per day in US. And in some European countries 90% drivers dive less than 40 miles per day.

3.3 kW charging station will eliminate 90%+ of need to plug in. It will recharge more than 80 miles in ten hours for Model S.

No need to oversize such system, well at least initially. 3kW should be more than enough. And then, if 3kW is a success, then may be go to 6 kW or 10 kW - but from practical point 3 kW should allow majority of drivers to go for months without need to plug in at home.

- - - Updated - - -

I appreciate your enthusiasm, but there is a very fundamental reason why pluglesspower is producting in low volumes...there's very little demand for this product.

You can't assume that mass production will reduce the costs when this is inherently a niche market.

You think takeaway rate for wireless charging option for Model S/Model X would be less than 10%? Assuming option will come officially from Tesla(and covered by Tesla warranty and SC) and the option will cost around $2500.

 

[WarpedOne]

My wag estimate would be 30% of MS85 orders and 20% of MS60 orders.
Wireless charging is the next qualitative improvement, car 3.0.

 

[Rodolfo Paiz]

At 85%+ efficiency, wireless inductive charging is better than I had anticipated, and my wife and I would actually be interested in it. As Zzzz noted, that 3KW system is more than enough for most days: 90 miles of range in 10 hours, more than what we consume on any normal day. And my wife would be thrilled at just driving into the garage and having the car "charge itself" on most days.

Yes, one sacrifices some efficiency (~10%) in the name of convenience. But her current BMW 535 GT burns $0.30 in gas per mile, and my P85 Model S eats only $0.045 (at worst) in electricity. With wireless charging, I'd be paying a full $0.05/mile in electricity... still SIX TIMES LESS than what she now pays for gas. When you look at it from that perspective, it's not a bad deal at all... and the HPWC is always there for those few times when one wants 60 miles of range in one hour.

If a 3KW wireless charging option (85%+ efficient) is offered for $2500 on Model X, I'm in.

 

[Larry Chanin]

You think takeaway rate for wireless charging option for Model S/Model X would be less than 10%? Assuming option will come officially from Tesla(and covered by Tesla warranty and SC) and the option will cost around $2500.

Yes, with all due respect to the opinion of fellow club member Rodolfo, :wink: I believe the vast majority of Model S/X owners would never opt for this. Tesla knows that and they would never provide it for the foreseeable future. Owners could buy two High Power Wall Connectors at 20 kW each for the price of one wireless 3.3 kW system.

Larry

 

[woof]

Yes, with all due respect to the opinion of fellow club member Rodolfo, :wink: I believe the vast majority of Model S/X owners would never opt for this. Tesla knows that and they would never provide it for the foreseeable future. Owners could buy two High Power Wall Connectors at 20 kW each for the price of one wireless 3.3 kW system.

Once the second EV is parked in the garage, the realization hits that cables running all over the place are both ugly and in the way. Especially if the other EV has the cable inlet in a different place as the Tesla. With both our cars plugged in it's impossible to walk from once side of the garage to the other without jumping over or stooping under cables (well, one could open the car doors and slide through I suppose). Wireless charging (or automatic connections from below) would correct that, and look much better. Don't underestimate the value of a clean looking installation to the acceptance of technology, even at the loss of some efficiency (which the average person would never know about nor understand anyway).

 

[Rodolfo Paiz]

Yes, with all due respect to the opinion of fellow club member Rodolfo, :wink: I believe the vast majority of Model S/X owners would never opt for this. Tesla knows that and they would never provide it for the foreseeable future. Owners could buy two High Power Wall Connectors at 20 kW each for the price of one wireless 3.3 kW system.

I have no problem with opinions that differ from mine.

I can tell you right now what my wife will say: "if the charger on the wall is $1200 and it costs me an extra $1300 never to plug in again, I can afford to make that payment and I value that convenience. We still have your HPWC for that rare day when I need to fill up quickly." She's often getting out of the car with a purse, and stuff, and she's on the phone, and she grabs the kids... not having to plug in has a significant personal value to some people. I don't know what percentage of the Model S/X buyers that is, but I think at least 5-10% would be my best guess. Heck, the more I think about it, the more I like the thought too...