Electric Motor Efficiency Versus V8 Illustrated (Video)


There are lots of discussions on how electric motors are simply more efficient at turning stored energy to power than gas motors, right?  Here’s a project that demonstrates it visually.

This guy, David Robert, put together a V8 motor, but instead of using cylinders and pistons to drive the crankshaft he used eight solenoids.  They are simply converting current to a magnetic field, and pushing the crankshaft on its merry way. Somehow, using electricity to make a V8 go demonstrates the incredible complexity, as well as inefficiency, of the machine better than anything else we’ve seen.

We’re not even going to talk about the losses of the combustion process.  Do we even need to?

Have a look:

Our first impression is there are so many moving parts, right? All those parts are doing is to convert electric power to mechanical power, which an electric motor does as simply as this:

Hats off to Mr. Roberts for some amazing work and a great demonstration as well! (To “Randy C” too – glad it makes the grandkids happy!)

Category: General

Tags: ,

8 responses to "Electric Motor Efficiency Versus V8 Illustrated (Video)"
  1. Djoni says:

    Isn’t electricity wonderfull?

  2. Bill Howland says:

    The basic fallacy here is that Electricity is a basic fuel. It is not.

    A prime mover is always required. These days it is usually a boiler, connected to a steam turbine, or combining the process, in a gas turbine.

    Someone could take the exact opposite tack and say that since my solar panel system is only 12% efficient, I should get rid of it and replace it with a 30% efficient central station steam turbine, to get the same amount of electricity for my house.

    That said, the erector set style v-8 engine is quite cool. I’d be interested in the specifics of it, and whether he has actually tried to run a real load with it (in otherwords what BHP load will it run?).

    1. Ted Dillard says:

      As long as we’re being pedantic, let’s read what I wrote: “…turning stored energy to power” because I chose those words carefully. Fuel (fossils or otherwise) = stored energy, electricity in batteries = stored energy, and the point of using this as an illustration (and basic truth here) is that an electric motor converts stored energy to power much more efficiently.

      No fallacy whatsoever.

      Your solar panels, if you really want to make an analogy here, are energy convertors – taking sunlight and making it electricity. The comparable process in making gasoline is converting sunlight to prehistoric plant life. I’m not sure on the efficiency of that.

      The storage process would be the subsequent millennia required to convert that to “fossil” petrochemical products.

      1. finecadmin says:

        Photosynthesis is ~1% efficient. Chemical and seepage losses underground make it even worse, assuming we’re still bothering to keep count by that point. Oh, and that’s if the plant actually made it into sequestration.

      2. Bill Howland says:

        “…As long as we’re being pedantic…”

        Please don’t include me in that statement. I don’t say things merely to hear myself.

        I’m merely offering the point that articles which state electricity is always more efficient is very wrong-headed.

        A practical example:

        Everyone “KNOWS” electric baseboard heat and electric water heating are ‘100% efficient’.

        Since that’s the case, I don’t understand why Everyone and their Brother quickly put in Methane utilities where I live simply because they couldn’t stomach the monthly cost.

        1. Ted Dillard says:

          An electric motor at 80-90% efficiency is always going to be more efficient than an internal combustion engine (at 30-40% efficiency). Other than that, I don’t understand what your point is.

          And, for the record, while you seem to disparage this build as an “erector set”, (which you may or may not realize is a kind of cheesy kid’s kit of stamped steel parts), Mr Robert has fabricated this remarkable machine one part at a time, out of “…scrap metal and wood, odds and ends, bits and bobs”.

          1. Bill Howland says:

            Mr. Robert has made a remarkably novell machine, which is a true accomplishment. The erector set comment I made was just to indicate it was Home Designed and Made.

            It is noted, that, as you say, you don’t understand my basic point.

  3. Raymondjram says:

    It shows that it is still more efficient than a gas engine, because you can reduce the RPM to very low speeds, yet still get torque. A vehicle with this V8 motor needs no transmission!