Technologies That Make No Sense

The wireless electric vehicle charger.  Sure it's cool.  And convenient.   But as I understand it, the main selling point of electric vehicles is their energy efficiency (I personally like the driving feel of a torque-y electric motor, but that does not seem to be the advertised selling point).  If this is the case, then why the hell would one accept a 30% energy loss (wireless charging is generally considered to be about 70% efficient) because they were too lazy to plug in a cable?

This is against the backdrop of most electric vehicle owners having no freaking clue if they are actually saving energy and money or not (all they know is that they see the costs to fill their gas tank but don't see little numbers spinning when they fill their electric car).  As I have written before, they likely are not saving energy vs. a similar size gasoline engine car but may be saving some money due to the lower cost of fuels like natural gas and coal (vs. gasoline) used in electricity production.


  1. Russ R.:

    Stop thinking like an engineer and start thinking like an electric car consumer:

    You bought an electric car because you saw it in a TED talk, it qualified for a $7,500 purchase rebate, and you wanted to impress (i.e. sow the seeds of envy in) all your suburbanite SWPL friends.
    You don't care about ACTUAL energy efficiency, payback periods, or net present value calculations.
    You care about the APPEARANCE of being A) environmentally conscious, B) tech savvy, C) affluent enough to afford new, fancy, shiny toys.
    Paying another few thousand for a wireless electric vehicle charger achieves all 3.

    When you consider the target customer, this product might just make perfect sense.

  2. ToddM:

    Totally agree with you that the point of an electric vehicle that is appealing is the low-end torque. But, point of fact, wireless charging at the 5 W level is indeed roughly 70% efficient, but at the power levels for charging an EV, it should be feasible to achieve efficiencies in the high 90s (based on discussions with a colleague who actually worked on this sort of system). And I think the convenience is a pretty big consideration.

    I'm assuming the charge rate is something on the order of 2 kW (240 VAC * 10 A). If you lost 30%, that would be a tremendous amount of heat to dissipate.

  3. gofer1:

    The are SMUG cars and the owners are buying the SMUG along with the uptilted nose to show they "care."

  4. erzanon:

    I have a 500W portable shop light (aka really bright space heater). That's 25%.

    BTW, at 2kw that's 12 hours to fully recharge a you can go 60-80 real-world miles (without air conditioning).

  5. obloodyhell:

    }}} When you consider the target customer, this product might just make perfect sense.

    Only when using the thing an ephtard liberal twit uses in place of "logic". But yes, you're essentially correct, it only makes sense if you're a total moron.

    I would grant that it might make some sense at "public" charging stations that run off solar panels -- since they're public, they'd likely get destroyed by idiots not unplugging them or running over the cables pulling in. Since they're solar you aren't burning any fuel to make the electricity, and if you aren't doing something with it right then it's worthless.

  6. obloodyhell:

    }}} And I think the convenience is a pretty big consideration.

    Right, except "convenience" is supposed to be subordinate to "sustainable". If "convenience" was a major factor, you should have bought a Honda Civic with a VTEC engine, instead. Cheaper to buy, cheaper to maintain, and much, much better for the environment as well.

  7. NL7:

    The main point people use to talk about hybrids, electrics, etc. is how infrequently you get a fill up at the gas station. So not even plugging in the car is even more convenient. It's actually ideal - a car that goes and goes without ever doing anything special to fuel it up (as long as you regularly return to your own garage).

  8. Morven:

    I think a lot of the environmental benefits of an electric car is that people will accept more compromises in one, it seems. They will put up with lower power, lighter weight, smaller size a lot more readily than they will in a conventional vehicle. Lower power, lighter weight, smaller size means better economy, not the power source.

    Of course, electric is also a way of exporting pollution to a remote generating station (valuable in certain urban areas which trap pollution, e.g. Los Angeles) and give more fuel flexibility.

  9. john mcginnis:

    You would be surprised how few people ever end up with the $7500 rebate. Many dealers have back channel where they on paper show they have sold the vehicle, recoup the rebate themselves and don't inform the customer.

  10. john mcginnis:

    What the electric car owners don't realize is that from an engineering point of view you lose about 20-30% of the btu value in converting that prime mover fuel to electric.

  11. mesocyclone:

    I agree with the sentiment in general. But... if they use resonant coupled charging, the efficiency can be a lot higher.

  12. Bill Drissel:

    Save money? Until they put road tax on the charging electricity.
    Bill Drissel
    Grand Prairie, TX

  13. marque2:

    I agree with you completely. We would get better mileage if GM would just start making GEO Metros again but who would want to buy a tiny car with small motor like GEO Metro even with the 55mpg. But take a Metro sized car and put in an underpowered electric motor and some batteries and they become all the rage even though they are less efficient than the equivalent small car.

  14. Michael:
    George Carlin has some things to say on this too.

  15. David:

    Would there be a way for an induction pad to charge multiple cars simultaneously? At that point I could see a benefit for adopting this as a standard by people like garage owners, but there would have to be a way to meter it, and it still wouldn't be as efficient - but perhaps it could avoid having multiple types of connectors...

  16. Imo Maru:

    You knew I was innocent, so why was I banned from the forum?

  17. Morven:

    If you need to talk to me, my email box is always open. Stalking my disqus comments instead is counterproductive. I'm the same name on the gmails.

  18. Imo Maru:

    Fuck yourself, old man.