FAQs
I have always seen battery technology as the weak link in EVs.
I thought I might shed some pounds from the vehicle if I were to replace the battery bank with a Kohler or Onan marine generator – I have one of each and they both run about four hours on a gallon of gas. [@ 50mph = 200+mpg !]
The problem is that these generator engines are not very efficient and are certainly not very clean. In the end you may end up doing a whole bunch of work to make your own “hybrid” and end up with something that pollutes more than the original engine AND gets worse gas mileage.
Also, unfortunately, you can’t always do math like: 4hours * 50mph = 200mpg. Why not drive 100mph and get 400mpg?! But seriously, 4 hours supplying how many watts? At what voltage? My first EV sucked down 75amps at 120 volts while driving on flat terrain at 35mph. That’s around 9,000 watts. Generators usually put out AC, which will need to be converted to DC (you lose power at each conversion step).
I did a quick search and found a 10kw generator for around $2,200. It weighs 300lbs which is more weight that needs to be hauled around, more weight, lower car efficiency (even with a gas auto). Also, I suspect if you ran a typical generator set at full load it would suck gas like there were no tomorrow and die an early death. You can get heavier duty gensets, but they will cost more, weigh more and still not be as efficient as a purpose made setup like a Toyota Prius.
The bottom line is that trying to simply turn gas into electricity to power an electric motor will typically use MORE gas than just keeping your existing gas engine. The reason hybrid vehicles do a good job is that they are precisely engineered to use electric power (via batteries or generator) to power the vehicle at take off, slow speeds and during heavy loads. This way the gas engine can run at its most efficient, with the electric filling in the rest of the time. They can then use a smaller and more finely optimized gas engine that way and, thereby, get better gas mileage. More info here
In regards to your comment on the idea of using an electrical generator to power or recharge the battery, there are very efficient 4-stroke generators now available that can produce the approximate 10kW of power needed to power a car. If however, you used the battery as the prime supplier of electricity and used a smaller more efficient generator to produce electricity it could extend the range of the car with out adding significant weight. Imagine using your electric car to drive 200 miles. While you are driving, the small generator is slowing the rate at which the battery is being drained and when you stop for a lunch or bathroom break the engine continues to run (automatically) recharging the battery.
You might want to check with the Controller manufacturers. I don’t think they want high charging voltage going through them, while the car is going down the road.
the gen idea is not that far out of reason. Forget the batteries. Trains use the setup to pull very heavy loads. You could use an ac motor since you have a revers gear in your car, you do not need to use a dc motor. You could also try hooking up your catalytic converter into the exhaust line, but may need a free flow muffler. Your gas usage would be determined by gal/hr. City driving may not be to good, but highway comuting should be really good. In the end, you don’t know if you don’t try.
So, I was a car service driver in New York for about six years and got sick and tired of paying for ever increasing gas prices and fixing my car (I will never again buy a front wheel drive Cadillac my 2001 DeVille ate up $50,000 in maintenance in just one year, Northstar sux). Last year I moved to the Lehigh valley (by bicycle) and don’t really drive much any more. A couple of weeks ago, I went home and picked up my trusty old ’96 Town Car, and plan to use it to go to and from New York, for visiting family and such. It’s about a hundred miles each way, and I’m not really impressed with battery performance, and I expect I can easily generate 10kW using the old 4.6L V8 that it came with. The question at hand is are there motor/controllers available that can push that kind of weight around in the 12-24V range, while I get my backyard flex-fuel turbine generator working?