Wireless Electric Vehicle Charging Moves Forward, In Long Beach Buses

By · May 13, 2013

Wireless charging is already in operation at Utah State University

Wireless charging is already in operation at Utah State University in Logan.

The battle cry to “plug in” your car might need to be adjusted, because wireless charging of electric vehicles is getting real. WAVE Inc., a company spun off from Utah State University, recently won contracts to provide its inductive chargers for electric buses in Long Beach, Calif., and for the Monterey-Salinas Transit Authority.

The buses will be produced at a new U.S.-based plant of BYD, the Chinese car company. “BYD wanted to use its own (plug-in) chargers,” Larry Jackson, president and CEO of Long Beach Transit, told PluginCars. “I said why don’t we try to see if we can get something that pushes the envelope technologically instead of just plugging in?”

WAVE’s wireless charger can recharge vehicles with an air gap of eight to ten inches, WAVE board member John M. Inglish told PluginCars.com at the opening of a BYD bus plant in Lancaster, Calif. a few weeks ago.

The vehicle can also be misaligned up to 6 inches on either side. WAVE said it demonstrated a 90-percent electrical transfer efficiency of 5 kilowatts over an air gap of 10 inches.

Those claims are based on results from a prototype 40-foot transit bus using WAVE’s wireless charging already in operation at Utah State University in Logan. It began running test routes in November, said Kate Peterson, marketing and business development manager at Utah State University Commercial Enterprises. Utah State holds the patents to the technology, she said.

Breaking Barriers to Wireless EV Charging

WAVE is about three years old. According to the company, the start-up uses a cost-effective process to produce ferrite, the material used to pass and shape the magnetic field without losing energy in the form of heat. WAVE’s method reduces the cost of ferrite from $1.50 a pound to less than $1.00 a pound, WAVE claims. The second key material, according to WAVE, is litz wire made from typical copper strands but with many specially-woven strands.

The $14 million BYD contract is for two wireless charging stations at the Queen Mary in Long Beach, Calif., according to WAVE C.E.O. Michael Masquelier. WAVE’s system is designed to be used with any kind of vehicle, said Masquelier. The company also has a contract to build a wireless charging station in Monterrey for a trolley that currently runs on a diesel engine, he said.

Representatives from Long Beach Transit went to Utah to check out the demo bus and make sure the chargers worked before committing to using them, said Jackson, an EV enthusiast who owned one of the original EV1 electric vehicles from General Motors.

The only potential barrier to using them, according to Jackson, is a potential lack of communication between BYD and WAVE.

“The big issue is making sure the recharging system talks to and properly recharges the batteries that are on the (Long Beach) bus, a fairly complicated issue,” said Jackson. “They have to make sure the engineers on both sides are communicating with each other to make sure this works.”


· · 1 year ago

What is the efficiency?

There is no reason to lose more than 10% of the energy for this. That is a lot of energy we are talking about here....

· · 1 year ago

@Modern Marvel Fan

Assuming it takes the driver 120 seconds on avg to plug in and unplug the bus and flip the Safety switch twice, try to calculate the effective pay per hour this guy could be paid to compensate for the 60 kwh loss per charge.
Let's see, say $5 loss per charge, at 2 minutes extra work, so that's $150 / hour.

I vote for pay the bus driver. its cheaper.

· · 1 year ago

@Modern Marvel Fan
@Bill Howland

You are right, but I think you are missing the point.
The bus can be cahrged at every stop it makes.
It is probably still not very practical, but if the technology is evolved the range will be higher with constant even small charges.

· · 1 year ago


A typical bus stop is what, 2 minutes? With the demonstrated 5kW, that's a whopping 5000 * 2 / 60 = 167Wh per stop. Most cars would get about 1/2 a mile (~2600') on that energy. A bus wouldn't get 1000'. I can't imagine this being helpful. If instead you are talking about a bus depot, where they could easily sit for an hour, how much hassle is it to plug in the bus? I agree with Bill - pay the bus driver to plug in the bus.

· · 1 year ago

@ Brian

OK. I agree and as I said the technology is not yet practical.
If you are going to charge for an hour than it's realy stupid to use wireless.
But if they upgrage the technology to use for ex. 15 or 20 KW and it gives you 1 mile of
run on 4-5 miles to the next stop than its 20-25% of your drive.

· · 1 year ago

Ok obviously we aren't all engineers or mathematicians. So let me break it down for you. @ 25kW (which this bus charges at according to every other source, typo in the article) @ 10 cents/kW hr average cost and 90% efficiency, a 5 minute charge would gross 2 kW hours or 20 cents of power. You would net 1.875 kW hrs and lose .125 kW due to loses in the system. Which amounts to 1.25 cents! SO YOU TELL ME IT'S WORTH THE DRIVERS TIME TO PLUG AND UNPLUG EVERY TIME THE BUS CHARGES??? (The idea that it charges at several stops on it's route...this is why wireless makes so much more sense!) Another thing is did you know that even plug in electronics are only 75-90% efficient from the outlet to your device? Anytime you have to change AC to DC you have significant loses. Just to educate those out there why wireless is plenty capable and in situations like EVs actually can end up saving time and money over plug-in alternatives!

· · 1 year ago

Ok, I admit that I didn't do any legwork to check the specs on this bus. Yes, the demonstration was at 5kW, but if the bus can really charge at 25kW, then that's a little different. Obviously, charging at each stop is not yet fast enough to handle 100% of the bus' needs, but if it extends the range 20-25%, that's significant. But don't forget the cost of installing these chargers at hundreds of bus stops.

I don't pretend to dictate what will be deployed and what won't - that's for the market to decide. But wireless charging, to me, still feels like a solution in search of a problem.

· · 1 year ago


Oh, boy, I hope your bridge building skills are better than your electrical ones. The input to your charger is 27.777 kw or 2.77777 kw loss at 90 % efficiency, not .125 kw.

Wireless losses are typically stated in addition to the losses in the car's charging system, so your comment isn't germane there.

Categorical statements such as AC to DC conversions are always inefficient is total nonsense, at least for the past 50 years. In my volt, the big efficiency loss during charging is battery charging efficiency of the battery itself, the electronics being in the upper 90's, both at 120, 200 and 240 volts.

My Tesla Roadster on the other hand is extremely inefficient at 120 volts, and somewhat inefficient at lower and higher 240 volt rates. Optimum is 30-40 amps. According to Toyota, all 240 volt charging on the Rav4EV is very efficient, with only 120 volt being extremely inefficient. So sweeping generalizations definitely do not apply to this subject.

Another thing: Where precisely is EVERY BUS STOP going to get the required 27.777 Kw for when the bus stops there 30 seconds? I could imagine a low cost solution myself, but then there would be a bit of capital cost involved, which I'll mention in detail if anyone is interested. It certainly can be done. Flywheel storage busses have been tried, but I'm not convinced they are economic at this point.. But its hard to listen to someone who thinks everyone else is dumb when your own numbers don't add up.

· · 1 year ago

@Bill Howland:
MechEng was talking about a 5 minute charge, not an hour.
So his figures are correct.

Wireless charged buses have been on the streets in Italy for 10 years.

'Batteries are fully charged overnight at the depot and topped off at each charging point on the route, ensuring sufficient range for reaching the next charging station. The topping-off charge refreshes about 10 to 15 percent of the battery’s capacity and, according to Conductix-Wampfler, can be done while passengers board and exit. Buses serving Turin travel about 200 kilometers, or roughly 125 miles, a day without requiring a stop for a prolonged period or a return to the depot for charging, the company claimed.'


It works, and losses are negligible.
What's not to like?

· · 1 year ago

If it works in Italy it will work anywhere :)

@Bill Howland
"bus stops there 30 seconds"
I guess you' ve never been in public transport bus :)

· · 1 year ago


What's not to like? You are putting in all this infrastructure for a lousy 20% additional charge? Why not put in a 20% bigger battery in the bus?

Lets ask the green eye shade guys which is the most efficient use of resources.. No one here has even mentioned that they have a solution to this problem, other than myself. But a 20% bigger battery is still far preferable.

25 kw charge for 1/12 of an hour is 2.08333 kwh, or 21 cents using his numbers.

The loss is .2315 kwh or around 2.3 cents.

Now people are going to split hairs and say he Meant to say 25 kw drawn from the power line and 90% of that going to the bus... Ok then that is 22.5 kw sent to the bus and 2.5 kw loss so 1.875 kwh to the bus , and .20833 kwh loss, not .125 kwh (he said kw but assumedly he meant kwh)

So he really shouldn't be criticizing other's math when he is the one who cant count straight.

· · 1 year ago

To implement a bus stop charger, the easiest thing to do it to have 2 insulated pipes on a springloaded shaft rotate up to a 'street light arm' by the bus stop. This would contact 2 dc wires to charge the bus at around 300 volts at 83 1/3 amps, or some other combination to get 25 kw with over 99% efficiency. The bus could signal the stop that it is there, if necessary, by radio signalling, otherwise, an even simpler approach would be when the bus is detected, just start charging,. When the bus drives off, the shaft would rotate backwards, lowering the 2 small pipes back onto the top of the bus. This is just a simplified version of a 3 phase , 3 pipe version being used for flywheel busses.

· · 1 year ago

There is one application around here where this could make a bit of sense. There are 3 busses total that drive between 2 college campuses and make no intervening stops.
So there are only 2 stops total. They sit about 10 minutes at each campus, which would allow the 'rotating' arm deal on the last post. If the charger gave 600 volts at 150 amps that would be 90 kw , or 15 kwh per charge/stop. This is probably enough to drive the bus the 6 miles between the campuses, or at least enough to almost make it, assuming the on board battery was a fairly decent size. These busses repeat these trips several times during the day and evening, so each 10 minute stop at 15 kwh per stop would replenish a significant fraction of juice, and since there are only 2 stops period, its economic.

· · 1 year ago

The system of wireless charging is only one possibility for an automatic system, since simple conductor contacts can also be placed on the ground in a secure way if they sit on a little bumper to prevent water accumulation and have a proper electronic securing or at least high weight security closure contacts at the wheels position that close the current. That would mean zero losses and a cheaper system.

On the other end the wireless system is impressive in the way that it can charge up to a distance of ten inches. It charges at that distance with a said efficiency of 90% but I suppose that in more normal conditions of a distance close to one or two inches, the efficiency rises higher which then change the interest of the system. I wonder what that more “normal” efficiency is?

· · 1 year ago

@bill howland
First you dont know what a mechanical engineer does. We dont build bridges. Second my math was sound at the five minute charging time during a stop. It is true that ac/dc conversion is the largest source of losses in these situations. I work with these systems everyday. Ill just say I work for a company that is a electric vehicle systems supplier to the auto companies.

· · 1 year ago


The skill sets are similar, and yes I've gotten an "A" in Calculus based Thermodyamics and a B+ in Fluid Mechanics. So lets not belabor this subject. I'm sorry but your loss number is just plain wrong. It's the height of arrogance to state people's numbers are bad when yours don't add up. Reread my response to Davemart. The Correct numbers are there..

Ac to dc conversion systems are not inherently inefficient. My family had a 1960 'transformerless' half-wave voltage doubler power supply in a 19" Westinghouse portable TV. The Electrolytics had a power factor of much less than 1%, and the drop in the diodes was not even a volt under cyclical peak , and the reverse leakage was trivially small, so the efficiency was around 99%. Not too shaby at all for 1960.

· · 47 weeks ago

Great information there, Thank you for the share. I thought of also sharing about my new CHOE Qi Wireless Charger for Galaxy S4 I9500 (Wireless Charging Pad and Wireless Charging Receiver Included) which I bought at Amazon for $32.99
Works with any Qi-enabled device through an adapter or an embedded chip
Power Source: AC Adaptor plugs into charging pad
Freedom of Placement: No annoying magnets to align or secret spots to find in order to charge your device. The wireless charging pad is Qi standard, you can charge any Qi-enabled device today, tomorrow and beyond. Light indicator to show charging status.
It works well with Samsung Galaxy S4 smartphone.

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