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You're either missing the point, or ignoring it. Yes, you will eventually have to get gas. Duh. It takes energy to stop a car too. Energy that is wasted in conventional cars, but in hybrids can be at least partially stored. In the same manner, hybrids' engines shut down when not needed to provide propulsion.

Since you didn't bother to quote from the several posts I made, I'm not even sure which original one you directed your comment to.

I know about regenerative breaking. Regenerative braking is best in stop and go traffic, but if you drive the freeway, your return is minimal when compared to the energy used in driving.

You said it takes energy to stop a car. It does not take a lot of energy to stop a car. Nowhere near the amount used to get it up to speed. Only that small amount used by power brakes for a few seconds. (With non-power brakes, it takes only energy from the driver's leg.)

Yes, when you stop, the conversion of the large kinetic energy of the car to heat by the brakes wastes that kinetic energy. Yes, some of that kinetic energy can be diverted to recharge the hybrid. Of course this is a positive for the hybrid in stop and go.

I agree with most of what you said, but I'm not sure where you got the idea that I said you wouldn't have to buy gas, though. When I mentioned perpetual motion machine to someone, I was joking.

You don't need the "Duh" if we're trying to have a civil conversation.

You're either missing the point, or ignoring it. Yes, you will eventually have to get gas. Duh. It takes energy to stop a car too. Energy that is wasted in conventional cars, but in hybrids can be at least partially stored. In the same manner, hybrids' engines shut down when not needed to provide propulsion.

One of the bigger energy wasters in conventional cars is the throttle. I wonder why more hasn't been done about that; delayed valve closure could control power without as much need for throttling as conventional designs, or an alternator powered by the throttle could be used to provide "better-than-free" energy (in normal designs, the energy wasted in the throttle is converted into heat in an area where increased temperatures reduce efficiency; putting something there to harness the energy would provide free energy in addition to cooling the intake air. To be sure, the amount of cooling probably wouldn't be enough to improve efficiency much, but the harnessed energy would still be "better than free".