Thinking about Mother Earth News reminded me of one of their most influential and successful articles, describing the conversion of an Opel GT to a gas-electric hybrid, in 1979. Of course, hybrid technology has been around since at least 1901, but not much had been done with it, at least on a grass-roots level. And this conversion made for $1500 definitely fits that description: a 5 hp lawn-mower engine, surplus generator and traction motor, some lead-acid batteries, and some workshop tinkering. But it set off a pre-Prius boomlet: 60,000 of his plans were sold. Exactly how many were actually built is quite another matter.
Given what we know now, his claims of being able to cruise almost indefinitely with only a 5 hp engine to feed the electric motors and recharge the batteries are highly questionable; maybe at a steady 30 mph, perhaps. But it makes for a fun read, if nothing more than to appreciate how far the same technology that powers today’s Volt has come.
Hmmmmmmmm wonder how it would operate with a 8-10hp 150cc GY6 scooter motor on it to power the generator? (You know just hypothetically since I’ve got one lying around. Still attached to the scooter which I commuted on this morning, but you get my point.)
No, but I’ll take an Opel powered by a 500cc-or-so motorcycle engine/combo. I wonder what kind of economy and speed stats you could wring out of that, except for that it would have no reverse gear…
/browses eBay for CRXes
//pushes bridge of glasses into forehead
Iremember that article well. Always wanted to buy his plans and do it myself but something kept knawing at me. What kept gnawing was my understanding of physics. In other words, the 100 mpg carburetor kept coming to mind.
I suppose that a series hybrid could have a very small ICE if you are willing to accept a significant performance reduction in what GM calls “charge sustaining mode.” The problem is not steady state cruising; after all, variable displacement engines work on the principle that one needs a lot less HP to maintain a cruising speed than to get there. The problem is acceleration and hills. The article says the top speed of this contraption is 50 MPH which probably is drag limited, i.e. the puny ICE can’t overcome the drag at higher speeds. If you designed this car to be more of a parallel hybrid than series, so the motor can assist the ICE while accelerating and climbing, something like this might be workable, but electric only range will be very limited. Actually, if a Prius weighed the same as this conversion and had the same performance envelope, would it get 75 MPG or better? Quite possibly.
Incredible! Just got back from the first class of this term’s Electric Vehicle Engineering course I’m co-teaching at Portland State, and here’s the same stuff on CC! In fact one of tonight’s slides was on the different forms of hybrid drivetrains, series like this, series-parallel like Prius and so on. Uncanny.
That’s a remarkable project, practical but surely slow. Mainly due to the 48 volt electric system, not the small engine. EVs with DC motors that can cruise and accelerate at freeway speed are at least 100 volts, and upwards of 500 amps peak. The 5 hp engine limits the long-term power, but not the short-term. I agree, 5 hp is not enough for 60 mph cruising, OK for 30 around town.
75 mpg is very green on the CO2 side. No mention of the immense smog-type pollution from the uncontrolled lawn mower engine. Probably worse than a hundred new cars. But so what, it’s radical, cutting edge and home-brewed.
Here’s a VW Squareback conversion done in ’77 with a similar electric drivetrain, surplus aircraft starter motor and 36 V, but without the engine-generator part: http://www.evalbum.com/2159 Slow and funky but it does run. Check out the sideburns in his photos there.
Electronic controls have come light-years from those days. You could do a very nice series hybrid like this today with a small (clean) scooter or motorcycle engine and a modern controller.
MEN wrote a big followup article in 1993:
http://www.motherearthnews.com/Green-Transportation/1993-06-01/Hybrid-Electric-Car.aspx
They said they were so skeptical they built one themselves, based on a 1973 Subaru. That’s right, an old hippie Subaru like today’s Curbside Classic. That can’t be a coincidence….. Whoa, this means something.
Here’s a proper electric Opel GT:
http://www.evalbum.com/3548
156 volts, drag racing controller, lithium batteries – this one goes.