New fuel efficient cars

[CraigD]

Originally Posted by Zythryn

For $36,000 you can have a Prius that gets 100mpg (varies from 75-150mpg depending on driving style and distance). That is about 2.4 liters/100km.

I assume Zythryn’re talking about a plug-in-Prius, an after-market conversion done by hobbyists and a few professional installers.

Though I’ve been holding onto an aging car and flirting with the possibility of 1-year leases in anticipation of Toyota offering a factory plug-in option, I’m beginning to despair of that ever happening, and considering the $10,395 Hymotion conversion.

Plug-in hybrids like this aren’t actually more mechanically efficient than ordinary gas/electric hybrids – if operated for long distances, or if they can’t be recharged frequently from an external power source, their fuel consumption either the same, very slightly better, or even worse than usual. Performance claims such as the common “100+ miles/gallon” are usually calculated by taking the current cost to the owner of the electricity used to charge the car and dividing it by the current cost of unleaded gas to get a “gallons of gas equivalent”, adding that to the actual at-the-pump gas consumption, and dividing that into odometer distance traveled. The same can be done with a pure electric vehicle (their actual at-the-pump consumption is, of course, zero).

Because of the additional variable and assumptions in these calculation, they’re subject to a lot of “creative interpretation” (eg: if I have a pure electric vehicle, and my landlord pays my electric bill, I can with some validity claim to get “infinite MPG” or “zero L/100 km”).

A good, though AFAIK rarely if ever used, source-independent energy/distance unit is kJ/m (kilojoules per meter), or m/MJ (meters per megajoule). For typical unleaded gasoline, a typical passenger car energy efficiency, 23.5 MPG = 10 L/km, equates to 34.6 kJ/m = 28.9 m/MJ (source: wikipedia section “Energy density in energy storage and in fuel”, and a little simple arithmetic).

[CraigD]

Originally Posted by DFINITLYDISTRUBD

… (I already thought they'd be a cool toy, but this would make it possible for me to make the thirty mile trip to work with the lil bugger and then after the trip home (ten hours of charge should be more than enough I'd think) …

It’s important to run the numbers on small solar chargers for EVs. Otherwise, you’re likely to find yourself stopping somewhere between home and work, rather than at either destination.

The Zap Zebra solar charger is 150 W (presumably in bright sunlight conditions). Let’s assume you have a very efficient vehicle, with an equivalent gas fuel consumption of 1 L/100 km = 235 MPG. That’s equivalent to 289 m/MJ. 150 W x 3600 s/hour x 6 hours = 3.24 MJ. 289 m/MJ x 3.24 MJ = 0.936 km = 0.6 miles. So you’d need about 50 of these solar panels to handle a 30 mile trip on a 6 hour charge, assuming a nice, sunny summer day at a low latitude.

This is why solar-powered cars are very exotic vehicles. GM’s 1987 Sunraycer cost about $2,000,000 (in 1987 US dollars), had about normal car dimensions (19'9" long, 6'7" wide, 3'8" high, with lots of ground clearance to avoid ground effect losses) almost completely covered in state-of-the-aerospace-art solar cells producing 1,500 W in bright Australian summer sunlight, massed only 390 lbs empty, a state-of-the-art motor, all to carry a driver only to a battery-boosted top speed of about 65 MPH, a solar-only speed of 36 MPH, and a 1,867 mile race average of 41.6 MPH.

The 2005 World Solar Challenge champion, the Nuna3 averaged 64 MPH, after which the race imposed a solar cell area limit, dropping the 2007 winning Nuna4 to 56.5 MPH. Like the Sunraycer, these’s are exotic, expensive piece of state-of-the-art aerospace technology.

These exotic cars show that, in principle, a solar-powered commuter car is achievable, but takes more than a sort of golf cart with a 150 W solar panel on the roof.

[DFINITLYDISTRUBD]

Where did you get that handy tidbit (Zap Zebra solar charger)? It's rather different than what is inferred at their site

ZAP will offer a new photovoltaic panel option for its three-wheeled Xebra Xero models. Xebras get their main charge from a standard 110 volt outlet, but the solar panel can power short-distance trips all on its own.

the bolded and underlined is rather misleading...Which apparently is how the company operates in general according to a rather long article @ Wired...dammit! Oh well back to just dreaming about electric rides like http://www.zapworld.com/electric-veh...cars/zap-alias
Yeah that would fit the bill nicely.

• 0 – 60 mph : 7.7 seconds
• Vmax: 100 mph
• EV range: 100+ miles (160.9 kilometer)
• Vehicle curb mass: 1612.6 lbs (733 kg)

[Zythryn]

Craig, quite correct. It is an add-on which the car companies are not yet offering.
The mileage does depend largely on how you drive, as you said.
If you are driving cross country, and that is all you do, I wouldn't waste the money.
If you make short, 10 mile round trips and can charge between them, you can get 150mpg. For my type of driving (city driving most round trips less than 35 miles) I am expecting, and so far getting about 100mpg.
And I agree, the solar is a gimmick at this point. The solar cells just aren't efficient enough yet to power very much at all. Some day, but not today

All electric are still the way to go, and they are coming soon, but not yet today either (on a large scale that is).