A small and efficient constant speed generator efficiently creates DC current at a constant voltage. Ignited by a tiny electric storage unit.

Refill at gas station.

In time, this type of battery will replace all current batteries, since fuel is so much more energy dense.
-- pashute, Jul 08 2013

Series hybrid http://en.wikipedia...ybrid#Series_hybrid
[xaviergisz, Jul 08 2013]

Micro APU Micro Hybrid Car Micro_20APU_20Micro_20Hybrid_20Car
I think this earlier idea completely covers this new idea [scad mientist, Jul 09 2013]

Supercaps used in lieu of a car battery. http://www.youtube....watch?v=z3x_kYq3mHM
and it works. [FlyingToaster, Jul 11 2013]

Is this intended to replace the battery in a regular car? If so, why is it better? Why is energy density a consideration?
-- MaxwellBuchanan, Jul 08 2013


Some aeroplanes already do this.

Your generator will need to produce enough power to crank the engine - a few kilowatts - so it won't be *that* small.
-- spidermother, Jul 09 2013


The tiny engine of the battery needs a tiny battery to start. The gasoline is continuously supplied by the car's fuel itself. No need for battery anymore.

Future benefit: Smaller batteries for everything.
-- pashute, Jul 09 2013


If I may be so bold as to restate the idea:

An electric vehicle is proposed, in which a minimal battery/supercapacitor is constantly recharged by a small gasoline powered generator, sized such that at its most efficient output point, it supplies the equivalent of the average power requirement of the vehicle. The battery is sized so as to be only large enough to store enough energy to provide for short transients in demand above the continuous output of the generator. For the periods in which the battery/supercapacitor is drained and additional power is still required, the generator may be made to operate at a higher power output, above the maximum efficiency point.

If this is a correct restatement of the idea, you've just described what is already known as a "series hybrid".
-- Freefall, Jul 09 2013


Mmm yes but I love the idea of the fuel tank and IC engine being packaged inside a battery casing so it can be swapped into any battery powered device.
-- pocmloc, Jul 09 2013


I guess the question is: can you build a generator, a fuel tank for the generator, a starter system for the generator, and a temporary accumulator to allow the generator to provide enough power to turn over a big engine, in a space smaller than a regular 12V battery, and for a comparable cost?

I suspect the correct answer is no.

The problem with the idea is that it doesn't say what it meant to achieve. What are the shortcomings of a car battery that will be solved by replacing it with a small generator, starter system, accumulator etc etc?

Put it another way. Imagine an alternative reality where every car had a big engine to drive with, and a small engine to start the big one. After decades of frustration with the temperamental small engines, someone comes along and says "Hey! I've invented this thing called 'battery' - it's only the size of a shoebox, it has no moving parts, and is way cheaper - whaddya think?" I think he would make a fortune is what I think.
-- MaxwellBuchanan, Jul 09 2013


Maybe its engines all the way down...
-- prufrax, Jul 10 2013


WIth a little bacterial flagellum to start things off?
-- MaxwellBuchanan, Jul 10 2013


The thing is that gasoline has SO MUCH more power to weight AND volume than any known battery, that the making of a small (rc plane) engine sufficient for generating the output of a car battery, would probably EASILY fit into the space of a car battery, and max's suspicious no gets the marking of incorrect.

No Freefall that's not what I proposed. Sorry.
-- pashute, Jul 10 2013


Most RC plane engines run on alcohol or nitro fuels, don't they?
-- Alterother, Jul 10 2013


The question remains - why? A car battery occupies less than a cubic foot of space, and weighs, what, about 10kg?

And in its favour, it has no moving parts and, in general, needs no maintenance.

Why will my car be better with a little model engine in a box?
-- MaxwellBuchanan, Jul 10 2013


well... if there was (or could be) a 4kW (efficient) IC genset the size and weight of a car battery that would be pretty neat.
-- FlyingToaster, Jul 10 2013


// The thing is that gasoline has SO MUCH more power to weight AND volume than any known battery //

Not true. It would be true if you said "ENERGY to weight". But for a short burst of POWER, a battery and motor can compete very well against a gas engine.

Since you're trying to replace a battery with an engine AND generator, you'll loose for sure. Sure you might match the peak power of a cheap car battery with an RC plane engine running at some insane RPM with a muffler that cuts the noise level from painful to highly annoying, but that won't be reliable or cost effective. And as soon as you do that I'll go and swap out the old lead acid battery for some A123 Lithium Ion batteries and make you cut your size and weight by a quarter or something.
-- scad mientist, Jul 10 2013


To quote from one of the foregoing annos: //Why will my car be better with a little model engine in a box?//
-- MaxwellBuchanan, Jul 10 2013


Everyone seems to be overlooking the obvious advantage here—it would allow you to kick start your big block V8. See, normally the compression on an engine like that would be far too much to overcome with just your sissy little leg. But if you replaced your battery with a 50cc two-stroke engine/generator, you could start THAT engine by means of an extra pedal (perhaps a fold out design to the right of the gas pedal). Then the electricity generated could be used to run the regular engine starter (or perhaps just run the starter directly off the two-stroke).

I dunno about you all, but I'd feel pretty badass starting my monster pickup the same way I start my classic Hawg.
-- ytk, Jul 10 2013


Well, that depends on what brand of "monster" pickup you have in mind...
-- Alterother, Jul 11 2013


//Why will my car be better with a little engine in a box ?//

It might improve the electrics somewhat, and you'd have a portable genset for camping, etc. Of course mostly because it's a little engine in a box.

[+] <link>
-- FlyingToaster, Jul 11 2013


//Hawg

I don't think there is a rule about "No spitting in the halfbakery", but it's so unhygienic.

I think this would be a hit for smaller applications, I can imagine filling up my laptop petro-battery as petrol station on Sunday nights.
-- not_morrison_rm, Jul 11 2013



random, halfbakery