Performance Electric Car

That's kind of an older project. I have seen pictures of this car.

EVs (electric vehicles) are becoming more and more popular. There is a sub culture of individuals building these cars for personal use. I have a colleague next to me that is converting a Toyota right now. Kits are available online to convert cars from standard fuel engines to EV (either as a hybrid with a small fuel motor for recharging the batteries or as a standalone EV). You can DIY for about $8K to $16K depending on how much you want to spend on a donor car. I understand someone else around here has converted a Porsche 911 to an EV!

The real challenge is the battery system. Lead-Acid batteries are the cheapest, but offer the poorer performance. High capacity batteries with low weight are very expensive and the technology is not mature. However, the gates are open and EVs are finding their way into more and more driveways. This will, excuse the unintended pun, drive technology to produce better batteries in the future.

When you think about it this is really nothing new. Many cities have been running electric vehicles for ages. Tram cars use overhead wires in Dayton, Ohio and many other municipalities. There are electric buses on the street, too.

That's kind of an older project.... I have seen pictures of this car...when you think about it this is really nothing new

I must be missing something??

It's only 'old' in so far as it actually exists and isn't just a 3D CAD drawing and a load of hype.

It's not a 'standard EV conversion....'

...I know maybe motors in the hubs aren't actually new, but I've not seen 'em used in all 4 wheels on a car like this and I've not seen anything with performance figures anywhere near this good before.

Tesla Motors has been producing EV cars based on the Lotus Elise chassis. The company has sold out all they produced. I forget the numbers, but the production numbers were somewhere around 100 at over $100K each. I was almost tempted (they are here in Florida), but I am sticking with a flat six for now. ;-)

There are others that are high performance, but I just don't recall their names. The Mini was one of them, but the Mini was only a concept car, albeit a good one. According to my buddy who is building his own EV, the Mini was demonstrated about a year ago.

Keep an eye out! The Mini is just the beginning. Once battery technology advances a little more there will be more and higher performance EVs.

One critique I have about the Mini was where they mounted the motors. It is a bad idea to mount these directly to the wheel. The weight of those motors is significant and they become sprung mass. As a wheel hits any aberration in the road the wheel will attempt to follow the road surface up or down. With a large mass at the hub the inertia of that mass will adversely impact the ability of the tire to maintain contact with the road. That is why high performance cars are going to ceramic brake rotors to reduce un-sprung mass at the wheels.

I think I know why they did what they did. First, it is mechanically simpler. Second, it offers better cooling. Third, it probably saves space if they can tuck these motors into the wheels and make more room for batteries.

Cheers...

Good point about unsprung weight.

Re: unsprung mass......

....making it ride like an original hydrolastic mini???

The whole point is surely that even after all the time that's been spent on them, electric vehicles remain hugely overweight (and therfore costly) and often rely on 'secondary' energy. And when we're talking batteries, how environmentally sound is their production and disposal? Fuel cells might be on the right track provided we can supply them with a sustainable source of fuel. Personally I find it inconcievable that this is achievable at today's level of vehicle-miles, never mind tomorrows. What would be left to eat??

Hugh Price

Hi Hugh,

• The whole point is surely that even after all the time that's been spent on them, electric vehicles remain hugely overweight (and therfore costly) and often rely on 'secondary' energy.

Have a look at the Tesla Motors Roadster, you may be surprised at what is actually possible if you put your mind to it.

You are however correct on the use electricity generated using a fossil fuel but when you take it all into account they produce about the same amount of pollution as a gasoline powered vehicle but away from city centers where it is not as harmful to the general population.

They can however be powered from renewable energy sources like hydro, wind, geothermal etcetera and if this is the case they are superbly efficient and considerably more environmentally friendly than any of the current vehicles.

Something else is the acceleration and an electric motor can produce far more torque at slow speeds that any internal combustion and of the couple of high performance electric vehicles that are in existence you need to go to something like the Bugatti Veyron to beat them off a standing start.

The batteries are also a problem but as they are in an enclosed package that can either be disposed of safely or recycled relatively easily.. Compare that to the noxious substances belched into the air we breath in overcrowded cities, with road systems that are over capacity and packed with vehicle that are consuming fossil fuels while going nowhere.

I too remember hearing of the concept of putting the motors in the wheel hubs over 20 years ago but as was pointed out the problem is the mass of the motor results in atrocious handling characteristics.

However, there have been a lot of developments in the field of electric motors over the past 2 decades and the use of rare earth magnets has resulted in dramatic improvements in their power to weight ration so it may now be possible to make the concept work.

It may very well be possible to build a brushless DC motor (really a version of stepper motors) that have sufficiently low mass to mount in the wheel hub and not degrade the suspension to the point the car is un-drivable.