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UK Students Build Electric Car With 248-Mile Range
da_how writes "A group of students and graduates at Imperial College London have built an electric car with a massive range — 248+ miles on a charge at 'reasonable' highway speeds (60 mph). They did this by filling the car to the absolute max with as many lithium iron phosphate batteries as possible — 56 kWh — and designing a very efficient direct drive powertrain, about 90% batteries-to-wheels at highway speeds. The choice of vehicle is an interesting one: it's a converted Radical SR8 — a track racing car with a speed record on the Nurburgring. Not an obvious contender for an endurance vehicle (no windscreen either!) — but then they claim it's lightweight to start with, being constructed of steel space frame and glass fiber. Also, Radical is based in the UK and provided some help and sponsorship. The students plan to drive their 'SRZero' 15,000 miles down the Pan American Highway, beginning July 8 in Prudhoe Bay, Alaska, and ending up in Tierra Del Fuego three month later. That's about 60 charges."
One thing glaringly missing from the article is the cost of the battery pack. On the open market right now, 56kWh of LiFePO4 cells runs a bit over US$120,000.
The Tesla Roadster has a 245 mile range. And basic stuff like bumpers.
The student car looks like it has about a 3 inch ground clearance. If that. That's not going to get very far on anything less than a perfect road. And they want to drive it down from Prudhoe Bay? Right.
That's something called "proof of concept".
What is the 'proof of concept' here? That if you make a bigger fuel tank you'll be able to go further? Sorry, but electric cars have been around for years. You can buy your own from Tesla Motors.
Attention... all grammer nazi"s! Is they're anything; wrong with: my post,
Some things really don't need to be proven. Sometimes, you can just apply a bit of simple logic to determine whether an idea is plausible.
Though, maybe I should propose to my boss that we experiment with my salary. If he increases it, I think I'll receive more money. But, just to be sure, we should do a proof of concept thing. Say a 50% bump just to try it out and see if it really works. If that works, we can do a 200% bump and let it run for a few years. If I'm still getting more money 5 years from now, we'll have proven the concept.
Not a bad experiment.
You'd be instantly first on the list of "people to fire when we need to reduce costs" and wouldn't probably reach the fifth year, disproving the concept.
One thing that stands out to me is that the rear spoiler and front splitter would make for a lot of aero drag, especially where the rest of the car is rather likely to be quite aerodynamically slippery looking at it's shape. They've also tackled rolling resistance and drive-train efficiency so any gains in aerodynamics would greatly extend range. At 60mph it's the greatest force acting on this car, and with their steps towards efficiency it is even greater. If they would just ditch the big spoiler and the front splitter, they'll watch their range shoot up. 0.50 to 0.30 cd might account for 40% improvement in a vehicle where rolling resistance has been already addresed.
Don't get me wrong what these guys are doing is great, but ~270 miles range is not terribly impressive considering that's what a stock Tesla has achieved.
Ditching the wing and splitter could have yielded them 20-40% improved range at open road speed, at the small expense of the race car look. It would take a few minutes with a spanner to remove, and to put back on for parking up for a photo shoot with the local press. I hope this is what they do. Some further work with some duct tape or some more ambitious aero mods with some coroplast http://ecomodder.com/forum/showthread.php/aerocivic-how-drop-your-cd-0-31-0-a-290.html ecomodder* style and they could have squeezed out more efficiency. The very best road vehicles approach 0.15 Cd, this would have given them a shot at 500 miles range. Lower the speed a little and they may have gone 600mi / 1000km.
I can't find Radcial SR8's aero stats anywhere but I know such track day specials have a fair bit of down force by design, so a drag coefficient above 0.50 is not uncommon. This is largely the result of the wings, air damn, and underbody design. High down force set up might be over 0.70 or more. To compare, a SUV is about 0.40, a good sedan 0.32, and a Toyota Prius 0.27, Aptera is about 0.17 these vehicles are not even designed not to generate lift let alone downforce.
* Yes I do lurk there.
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