why can’t an electric car charge its own batteries while driving to increasesupplement its range - either through a powered generator or by using the rotation of the wheelsaxle to turn a generator - or how about a hybrid that uses a small internal combustion engine to power a generator??? Multiple drive sources like a motor at each wheel would allow for frt drive
ear charge or vice-versa with full time 4 wheel drive for emergencys
Elementary physics tells us that you cannot create energy out of nothing; there is no perpetual motion machine! Putting a generator on the wheels assumes you can have a perpetual motion machine.
Having said that, an on-board engine (gasoline or diesel) to charge up the battery is what hybrids are all about. The new Chevy VOLT will do exactly as you suggest; it is an electric car with a plug in feature, as well as a small on board engine to charge up the battery as you travel.
So start saving your pennies, in 2010 the VOLT will go on sale early next year and you can have the car you dreamed of. But it will require both house current to charge up and the small engine to charge it up on the road.
In addition, current hybrids already do what you suggest - when you push on the ‘brake’, you are actually energizing the circuit that turns the electric motors into generators, partially recharging the batteries. Push harder, and you engage the normal brakes. Those ‘regenerative braking’ effects are a large part of what gives hybrids their improved fuel economy.
Thee technologies are already in use or coming soon.
Hybrids use regenerative braking to partially charge their batteries. The proposed Chevrolet Volt will use electric power only to drive the vehicle. The small gasoline engine will power a generator to partially recharge the batteries and keep the car moving until it gets to an electric recharging station.
The key word is “partially.” It takes more power to drive the vehicle than can be recaptured by these technologies. Perpetual motion remains a dream.
The old railroad passenger cars used the rotation of the wheels to turn a generator, which, in turn, recharged the batteries that powered the lights and fans on each railroad car. The voltage supplied to the lights and the blower motors was 32 volts d.c. Of course, it took energy to spin the generators on the cars. In earlier days the steam locomotive sent steam to the coaches to heat them in the winter and cool them in the summer by using the absorption principle. When the diesel locomotives came along, a steam generator was incorporated into the passenger locomotive. The energy required to turn the generators in the train cars was considerable, so the Amtrak cars are now heated and cooled electrically by 3 phase 480 volt power generated by a powerplant in the locomotive.
At any rate, the rotational energy is not free. If you have ever ridden a bicycle with a generator powered headlight, you will feel the drag as you engage the generator against the wheel to power the headlight.
Adding an additional generator to an electric car would simply add to the amount of energy needed to run the car. No device can produce as much energy as it consumes simply due to losses in the operation of the device itself, so you could not recoup the energy used to operate the additional generator.
The energy that operates a generator in a car, and the energy referred to in Triedaq’s locomotive, comes from the fuels they burn. It’s converted into various forms such as heat, inertial, and and electrical energy (charging of the battery, but both vehicles still need to go to their fuel sources to replenish.
In an electric car, the energy comes from the fuel used by the electric grid that charges the battery. Some of that is converted into inertial energy, and some of that inertia is converted back into electrical energy via the regenerative braking systems used by many hybrids, but the energy used to accelerate the vehicle, overcome wind and rolling resistances, and operate the vehicles systems is nonrecoverable…most of it actually is converted by one means or another to heat energy and dissipated into the air through and the ground over which the car travels.
To get a feel for how much energy needs to be used from the car just to go through the air, stick your hand out the window while you’re cruising down the road. Fell the pull. The imagine if your hand were as big as the crosssectional profile of your car.
I am not trying to create a perpetual motion vehicle - I realize that the it takes energy to make energy & most of the time it’s a losing proposition- I was merely trying to understand why my suggestions couldn’t be used to extend the range of an electric vehicle to a usable level - the range I’ve heard on the Volt is 40 miles - that would be on a complete charge under excellent conditions - “your mileage may vary” - I have a 100 mile commute everyday - My children and grandchildren live 150 miles from me - I would love to see the electric car become a reality, but no one is going to spend $25K+ or more on a car that sole function is to take the kids to school and get groceries - until the electric car can function as diversely as the gas or diesel does now ot wil never be a viable choice
By the way - thank you for your reply - I knew my my suggestions weren’t viable but I wanted to know the science behind why
Okay, let’s say you put a generator on one of the wheels and it gives you 200 watts of electrical power to put back into the battery. That 200 watts didn’t come from thin air, it came from mechanical power being taken from the wheel (increased drag). So, let’s say that took 250 watts of mechanical power from the wheel. (Yes, we are pretending that things are more efficient than they usually are.) Now, the drive motor has to supply an extra 250 watts of mechanical power to drive the car at the same speed. So, it takes an extra 300 watts of electrical power to keep the car going.
Your generator idea didn’t add range, it reduced it. (You gained 200 watts, but it cost you 300 watts to get it, so you really lost 100 watts.)
If everything were 100% perfectly efficient, you would break even at best.
Thanks again - that’s what I was suspecting and the answer I was looking for - but not having that kind of a background I could only speculate - you’ve been a great help
I like the bicycle example. When I was still riding, the club I rode with and I used to do night rides through the woods. I tried putting one of those generators on the bike just to see how well they worked…and immediately went back to batteries!
Blessed is the man who invented drycells!!!
Yes, drycells are great. It’s jail cells that I don’t like!
The charge density of batteries isn’t nearly high enough yet. If you consider the Prius as current generation, then we need two to three generations until the power density is high enough do do what you want.
Does anyone think a production Chevy Volt will ever see a showroom??
Electric cars with a small motor powering each wheel is coming, I think it is BMW that is farthest along on its development. Smaller motors are also smaller more efficient generators but the car has to be moving downhill in order to generate current to recharge the batteries. On level ground the motors have to use current to maintain speed due to friction, tires rolling resistance, and pushing air out of the cars way.
Other sources of power can be panels that convert sunlight to electricity on the roof, hood, and trunk of the car. When pure all electric cars are made they will certainly incorporate solar panels into the design.
These are techincal problems that have solutions but in some cases the solutions are just too expensive until refinements and scale of production can make them affordable in normal cars we can afford to buy.
Yup. Team Obama, the new corporate chiefs, want to see it. Our tax dollars will see that it happens.
They may be able to divert my tax dollars to building one, but unless it’s affordable and reliable nobody’s gonna buy it…except a few “buy American” tree-huggers…with excess cash.
The Volt’s range with battery and gas engine will be 400 miles. The battery-only range is 40 miles!
[b]The Volt’s range with battery and gas engine will be 400 miles. The battery-only range is 40 miles!
Does anyone think a production Chevy Volt will ever see a showroom??
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My sentiments exactly…hold your breath till you see it on the streets. The really range extenders are the innovators mentioned…regenerative braking, solor panels etc. (though what else etc. is I haven’t a clue) Down the road, I would think the sun belt would have a huge advantage in personal transportation; park in the sun, instead of the shade as we do now.
I wonder when the car heats up, if the air you need to drive away will use up the gain you had in the sun ?
So the closest thing to “perpetual motion” would be the ability top tap into energy resources as you drive, whether it be momentum, solar or neuromuscular transfer of energy as you snap your head around from looking at delightfully enhanced summer time scenery as you pass by a public beach.
The 400 Mile range from the Volt - if I understood the press release orrectly - is exactly what I was speaking about earlier - a small internal combustion engine whose sole purpose is to power a generator that charges the batteries - I am assuming that the range is limited to the size of the fuel tank and possibly the efficiency of the generator - I am not sure if the generator would be able to keep the batteries fully charged.
Yes. GM was waiting for the battery technology, but I think the battery technology is here in deep cycle lithium ion batteries that have an estimated life of 2,000 cycles. Like all new technology, the price will go down as manufacturing ramps up.