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Momentum dynamics claims 200kw wireless charging by end of year. Credible or crap?

Discussion in 'Model S: Battery & Charging' started by Gilzo, Apr 16, 2016.

  1. Bankroetlama

    Bankroetlama Member

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  2. JohnSnowNW

    JohnSnowNW Active Member

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    Does not seem plausible. An air-gap of 12", at 200kW, and equivalent efficiency to plugging in...nah.
     
  3. RandyS

    RandyS Fan of Elon

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    I recently had a conversation with some industry leaders about wireless charging, and the charging power they are talking about having good success with is much much less than 200 kW...
     
  4. AWDtsla

    AWDtsla Active Member

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    Claiming to solve a problem that doesn't exist. It's only "wireless" by a technicality, two pieces need to be aligned within a certain small tolerance. Might as well have wires at that point.

    Robotic charger is not only better, but it's cooler.
     
  5. kennybobby

    kennybobby Member

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    Maybe a 2 kW system? There were no products or specs listed on their somewhat useless website.

    Since air is such a poor conductor of magnetic fields compared to the iron used in transformers, it requires huge amounts of illegal drugs to even consider the possibility of passing the equivalent of 200 kW using magnetic field across a 12 inch air gap with an inverse square law.

    Evanescent waves, microwaves, resonant circuit pumps--baffle them with bs. There are tons of videos on the websticle that look just like that one with over-unity devices and free energy claims, show some digits on a meter and lightbulbs and declare victory, jesushchrist we just solved the world's energy crisis.

    Looks like someone is trying to make an efficient transfer device of money from your pocket to their bank account.
     
    • Funny x 1
  6. tom66

    tom66 Member

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    No reason you can't do 200kW, but say it's operating at 13.54MHz (pretty typical ISM band) this requires a lot of power semiconductors, very expensive, even something like 85% efficiency using say a Class-E resonator will be dissipating 15-20kW alone in the power semis, so the charger will necessarily be very large to achieve this (think about how much heating power the average home needs - say a UK home would be 25kW - this thing is dissipating almost that much heat! Removing that won't be easy!) The antenna patch will also have to be huge. Not impossible, but not possible in that form factor.
     
  7. Adm

    Adm Active Member

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    In Rotterdam, the Netherlands, experiments are being conducted with 11kW and 22kW and a 6 inch gap. They claim 90% efficiency.



    I'd like to know what our resident experts think about it.
     
  8. AWDtsla

    AWDtsla Active Member

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    22kW @ 90% means 2.2kW of heat lost just in heat between the two plates.. Secure your cats before charging!

    What's the total efficiency? multiply 90% by 93% for the onboard chargers, now you're at 83% efficiency, which is pathetic.

    Keep in mind, a wire of the right gauge and length has no problem being >99.9% efficient.
     
  9. SomeJoe7777

    SomeJoe7777 Marginally-Known Member

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    #10 SomeJoe7777, Apr 17, 2016
    Last edited: Apr 17, 2016
    Only AC can be sent across the air gap, so all AC->DC conversion must take place on board the vehicle. What vehicle is going to contain the AC->DC charger(s) capable of 200kW conversion other than maybe a bus or large truck/tractor? None of which are EVs at present.

    135kW in the Tesla superchargers requires a large cabinet with 12 individual chargers, cooling system, control system, fans, etc. 200kW obviously would be even larger.

    Efficiency of the AC transfer across the air gap can't be more than about 90% (even well-designed transformers with no air gap in their magnetic material only achieve 97%), so at 200kW of transfer, there's 20kW of heat loss in the transfer, and another 7% (14kW) in the chargers on board the vehicle, for a net 34kW of heat that needs to be removed. That's enough heat to keep a 4800 square foot house warm in the dead of winter.

    20kW of heat loss at the source charging plate under the car will require a liquid cooling system.

    Methinks there is something fishy with the claims here.

    Plus, even if such a system were built, it would never be practical from a cost standpoint. The cost of the hardware for the car, the additional cooling systems required, and the losses in efficiency mean that an automatic articulated arm solution would be far cheaper.
     
  10. Todd Burch

    Todd Burch Electron Pilot

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    #11 Todd Burch, Apr 17, 2016
    Last edited: Apr 17, 2016
    I vote for BS!

    I still prefer my design where your car rolls over a device fixed to the floor of your garage. The simple action of pulling forward slides open a window underneath the car (via a spring-loaded catch arm) and spring-loaded rollers make contact with metallic plates.

    Now you have the efficiency of wired charging and the ease of wireless charging. Plus you avoid the additional complexity of a robotically actuated charger.

    Would obviously require a different car design, but certainly doable and probably much easier than falcon-wing-doors!
     
    • Like x 1
  11. Gilzo

    Gilzo Member

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    Interesting.
     
  12. Larry93428

    Larry93428 Member

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    Interesting yes. But we have 130,000 cars out there that could use the arm system.
    What will happen to us?
    ~Larry
     
  13. Asciidv

    Asciidv Member

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    In London inductive charging is being trialled using Dennis buses. The pickup coil is in a box about 4 feet square by 3 inches deep in the centre of the bus floor, with about 6 inch ground clearance.
     

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