Quote:
Originally Posted by dcb
why not hook that 5hp motor to a 5th wheel and stick it in your tow hitch with a lever to raise/kill it or lower it?
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To achieve 50% efficiency you CAN NOT DO THAT, period!
Those motors are designed to work at ONE OUTPUT SPEED AND POWER VALUE.
Motors that vary output tend to all universally be below 30% efficiency, most being below 25% in real world. (and thats modern fuel injected, not a small gas engine)
If you DID do that with a single speed turbine you would move below 30% efficiency in a heartbeat, in fact most ICE engines in stop and go are only really about 5-10% efficient when not driven by a hypermiler.
Classic gasoline motors were always assumed to be about 13-17% efficient motor to wheels as an example mainly because they rarely operate at their efficient area. A 5hp standard motor is typically in that range as they are usually antique in their controls and tend to go rich during their operation.
Moving motor burn efficiency from maybe 25% (likely lower on a SGE) to 50% of a single speed turbine would do the most to improve fuel economy in that application.
Thus a generator powering an electric motor decoupled so it could only run at its most efficient range could likely still operate about 65% more efficiently (even with losses) than a classic variable throttle motor running through some sort of gear reduction system.
The battery losses would be hopefully very very neglidgable because the generator would normally be dumping its full rated load into the motor directly.
Cheers
Ryan