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Old 04-20-2006, 09:27 PM   #11
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I bet an electrified version

I bet an electrified version of this could go 200 miles on 800 pounds of lead acid batteries. Add in a 200 horsepower motor and controller combination(ie. Zilla 1k and a WarP 9" with a battery pack of sufficient voltage and low internal impedance), and there'd be no need to sacrifice performance. You'd have an EV that weighed around 1,400 pounds, 800 pounds in batteries, had 9 kWh of usable capacity, and needed about 45 wh/mile to travel at 60 mph highway speeds.

Such a car would theoretically top over 200 mph and do 0-60 in 4 seconds, using off the shelf components for its powertrain.
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Old 04-21-2006, 07:01 AM   #12
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Take it just one more step.

Everything Toecutter said is correct, but VW should take it one step further. NiMH batteries for equivalent performance would only weigh 300 pounds, and Lithiums would only weigh 200 pounds.

By the way, did you select your name because you ran a lawn mower over your foot?
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Old 04-21-2006, 07:06 AM   #13
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naaa

You can't just add that much weight and expect it to work because the frame / chassis is designed for light weight and can't hold that many lead batteries or power besides lead batteries don't give you the service life needed for a long range vehicle or the power density. That's the whole "making it bigger - makes it heavier" diminishing returns problem and is why SUVs get so big and heavy. As soon as something gets heavy then everything has to get beefed up to carry the load and in turn makes everything else heavier.
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Old 04-21-2006, 02:47 PM   #14
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Sludgy, watch Mad Max.

Sludgy, watch Mad Max. You'll find it quite apparent where I got my name then.

Also, I didn't include NiMH because Chevron owns the patent and refuses to allow EV sized modules to be made. Consider it no longer an option. It could be produced for cheap($150/kWh according to Energy Conversion Devices chairman Robert Stemple), but the oil company has a hold on it.

Lithium is not mass produced anything like lead acid is. Since no one is making electric cars, prices stay high. Although, one could argue that VW isn't making the lead acid car I'm proposing anyway.

I chose lead acid mostly to illustrate that with a design like the 1L, advanced batteries are not needed for a long range EV. Although the battery technology is here and workable, the auto industry keeps sticking to the tagline that it's not ready. But if it is possible to get long range on off the shelf lead acid batteries, their point is moot.

A Zilla 1k, WarP 9" motor, PFC charger, 18 Optima D750 AGM batteries, Regs, and all ancillary components could be added to a reinforced chassis for about $7,000, with the controller, charger, motor, and regs still being hand made. Add that to the cost of a reinforced chassis, and you have a roughly $20,000 EV with 180-200 miles range, performance like a Ferrari, and a $3,000-5,000 or so profit margin.

To replace 9kWh of Optimas with 9kWh of low volume lithiums at $1,000/kWh would bring the price tag up an extra $7,000, and maybe only increase range by 10-15% from reduced weight.

Mass produce the lithiums, on the other hand, and it would cost about the same as the lead acid version, since the battery pack would be so small.

As for lead not having the required power density? Optimas are about 500W/kg for specific power. We're looking at 250 battery horsepower for an 800 pound pack. Counting in motor/controller losses, about 200 horsepower meets the gears.

This would give a 0-60 time for a 1,400 pound car of roughly 3.5 seconds. Top speed would need to be governed well below what the vehicle would be theoretically capable of reaching due to stability issues.

Not enough life for consumer acceptance? Most people who use lead acid batteries and come to this conclusion tended to deep discharge them on a regular basis, and/or never had a battery management system. Optimas have repeatedly leasted 2,000 cycles to 30-40% discharge, but to 80-100% discharge, might only last 150-200 cycles.

Take the case of a lead acid EV with a 50 mile range, with a battery regulation system. If the owner always takes it 40 miles before recharging again, the pack will only last 6,000-8,000 miles, very typical of those who have EVs and routinely deep discharge their batteries. If he takes it 20 miles on average, his pack would in theory last 40,000 miles. But most people who drive that little only put on 4,000-6,000 miles per year, so shelf life will probably be the limiting factor.

In the case of this hypothetical VW, the range(calculated below) would not be 50 miles, but 180 miles. Even if the pack is routinely deep discharged(know anyone who drives 180 miles each day?), we're looking at a minimum 30,000 mile life. How? The car was designed for efficiency. Efficiency greatly improves battery life. However, in the case of this VW, age is likely what will do the battery pack in, not discharge cycles. Optimas have an observed shelf life within the EV community exceeding 8 years before they only deliver half their range, and about 6 years before they deliver 80% of their range. Talk to John Bryan and John Wayland, who each have packs of that age in their EVs, still delivering 60% of the original range. Further, with a BMS, AC Propulsion has obtained 20,000-30,000 mile life with Optimas on full size electric cars with typical 50-60% discharges. This puny little VW muse of mine could surely do much better!


To beef up the GVWR would require modifications yes, but given the size of the car itself they'd add no more than 50 pounds. Were talking a steel roll cage built into the body itself, not only for crash protection, but for chassis rigidity. The IC components could be stripped, giving a 'glider' weight around 500 pounds.

Motorcycle transmissions of sufficient strength for 200 horsepower are not very heavy, in the area of 40 pounds. For this theoretical EV, the tranny could be lightened by simplifying it to 2 gears, one for 0-90 mph, and the other gear for racing up to 200+ mph, possibly reducing the weight to 20-30 pounds.

Also, most horsepower requirement at highway speeds is from aerodynamic drag. Increasing the VW 1L from 640 lbs to 1400 pounds would require under 1 engine horsepower more to travel at 60 mph(assuming the 1L uses LRR tires with a Cr around .006).

At highway speeds, it's not the weight that kills SUV fuel economy, but their bulky inaerodynamic shapes that generate high amounts of turbulence. There are luxury cars of similar weight fitted with V8s that get considerably better mileage, infact similar to that of many 4 and 6 cylinder 'economy' cars available in America.


My estimate(from calculations) is that the 1L as is would require just 4.6 engine horsepower to cruise at 60 mph. Also, substituting the max speed of the car(74 mph) into the equations I used and calculating the required horsepower equates roughly to the peak horsepower of the engine, so it appears reasonably accurate(8.2 hp versus the 8.5 hp the engine really has).

Changing the weight to 1,400 pounds, the engine horsepower needed to cruise at 60 mph only increases to 5.5.

For an EV, 5.5 horsepower(4.07 kW) to cruise at 60 mph equates to 50.3 wh/mile.

For a 9kWh lead acid battery pack, this is 179 miles range. Plenty. And close to the 200 miles I estimated. It may seem surreal, but it is the efficiency of the vehicle that would allow this. A typical midsize car converted to EV like a Honda Accord will require 250-300 wh/mile at similar speeds, and even cars like such can get 30 miles range on 800 pounds of lead acid batteries.

The major caveat with my design is probably finding the space for the batteries. But the chassis could be redesigned from the ground up as an EV with that accomodated for, while maintaining most of its characteristics.

Lead can do long range, provided the car is designed for extreme efficiency.


The 1L is perfect for it.

Screw diesel. This thing could be an affordable EV that uses off the shelf batteries you can buy at a Walmart, accelerates like an exotic sports car, and still manages half the range of a gas car in normal driving conditions.


If VW would make them, I'd seriously consider converting one in the near future, advanced batteries or not.


===========================================

I estimated the frontal area at 13 square feet. We know the d is .16, and that it weighs 640 pounds. I also geussed the Cr to be .006, which would be a reasonable figure for low rolling resistance tires.

The equations used for the horsepower required calculations above are as follows:

Rolling resistance:

Fr = Cr * W

Cr = coefficient rolling resistance, no units
W = vehicle curb weight in lbs.
Fr = rolling force in lbs.


Aero Drag:

Fd = Rho * Cd * A * V^2

Rho = constant to adjust for normal air pressure, convert from Metric to American, and to account for the normally present in the formula Fd = * Rho * Cd * A * V^2, Rho ends up .002558
Cd = coefficient drag
A = vehicle frontal area in square feet
V = velocity in mph
Fd = aerodynamic drag force in lbs.

Total Drag:

Total Drag = (Fd + Fr) / S

Fd = aerodynamic drag force in lbs.
Fr = rolling force in lbs.
S = 100 percent minus 20 percent stray losses and written as decimal, so expressed as .8
Total Drag = Total drag force in pounds

HP = Total Drag * V / k

HP = engine horsepower required to cruise at speed
V = velocity in mph
k = 375, a constant to adjust for V in mph, drag force in lbs., and HP in horsepower

For estimating 0-60 mph, I used a formula commonly available on the internet and reasonably accurate:

(0-60 acceleration in seconds) = (weight in lbs)/(1.983*Peak Horsepower Output)


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Old 04-21-2006, 06:26 PM   #15
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what are we missing in parts

what are we missing in parts availabilty at much more reasonable (second-hand) cost to make this into a feasable backyard build...?
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Old 04-21-2006, 07:22 PM   #16
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cost of cf

The cost of Carbon Fiber will cost a small fortune and although light enough the steel tube frame will add yet even more weight and all that weight will consume more power to accelerate - figure out how much of the battery capacity will be used to accelerate to 60 and back down again a few times. Li-Ion cells have a much longer useful shelf life even with 50-80% discharge cycles too shallow and too deep shorten life a little more then mid depth cycles. and the saving in weight will save energy used during acceleration and deceleration. It's all been calculated before and it doesn't work.
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Old 04-21-2006, 08:07 PM   #17
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Would the defense/aerospace

Quote:
what are we missing in parts availabilty at much more reasonable (second-hand) cost to make this into a feasable backyard build...?
A chassis that is near as light and as aerodynamic as the VW 1 litre...

You won't find one in the U.S. You'll have to build it, unless you believe VW will miraculously sell this car.

Jerry Dycus is going the self built route with the FreedomEV. It's not as aerodynamic as the 1L concept, but with 700 pounds of batteries in a 1,500 pound car, he can realistically expect 100 miles range in normal driving, more in granny mode, considerably less with a lead foot. Drag coefficient is an estimated .24.

Quote:
The cost of Carbon Fiber will cost a small fortune and although light enough the steel tube frame will add yet even more weight and all that weight will consume more power to accelerate - figure out how much of the battery capacity will be used to accelerate to 60 and back down again a few times. Li-Ion cells have a much longer useful shelf life even with 50-80% discharge cycles too shallow and too deep shorten life a little more then mid depth cycles. and the saving in weight will save energy used during acceleration and deceleration. It's all been calculated before and it doesn't work.
Would the defense/aerospace industry not have a monopoly over automotive and aircraft quality carbon fiber, costs would be $10/pound. Or, assuming the vehicle has 300 pounds of carbon fiber in it, $3k. Low grade commercial tow is ~$8/pound, but the carbon fiber of sufficient quality to build a vehicle would not be much higher would action be taken against certain industries.

Yes, it will take more energy to accelerate a heavier car than a lighter one.

To accelerate from 0-60 at a modest pace to reflect typical driving habits, say, 25 seconds over a 1/4 mile distance, a 1,400 pound car would need roughly 17 kW of constant power over that interval. 17 kW for 25 seconds is using .118 kWh of energy for each acceleration from 0-60 mph.

Or, 1.3% of the energy stored in the battery pack for each run from 0-60. This is by no means crippling on range, provided you're driving like normal instead of with a lead foot.

Say you take a trip in this hypothetical car by highway, and have to stop 15 times due to traffic, stalled cars, ect.(1 stop every 10 miles or so)

You'd still go an estimated 144 miles on that charge. Again, this assumes no regen braking and you accelerate like normal. Driving with a light foot would reduce these losses. Driuving with a lead foot would no doubt increase them.

Of course, where I live, this many stops would be quite high once you're outside the city.


Suffice to say, with an aerodynamic chassis and reasonable weight(not superlight, but not a pig either), lead acid can do half the job gasoline can when it comes to range, at least with normal driving habits and a battery pack size selected for the job. Barreling down the highway at 150 mph and flooring it at every opportunity, and that's not the case.
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Old 04-21-2006, 08:08 PM   #18
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thin urethane will work over

thin urethane will work over the steel tube chassis
who cares about the CF if we have to go tubeframe anyways

i know basically nothing about different battery cell performance
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Old 04-21-2006, 08:36 PM   #19
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Quote:i know basically

Quote:
i know basically nothing about different battery cell performance
All you need to know in the context of this topic is that a lead acid battery generally can store 11 Wh of energy per pound of battery, while diesel has 5,500 Wh per pound.

Knowing this, and that an electric car can be built that only needs 50 wh/mile to cruise at highway speeds, it will blow the efficiency of the original VW 1L to hell, out of necessity if long range is to be achieved.

1 gallon of diesel = 38 kWh
800 pounds of AGM batteries = 9 kWh

You can see clearly EVs are at a disadvantage when it comes to available energy, yet their efficiency can make up for it.

(38 kWh/g)/(235m/g) = 162 wh/mile for the diesel 1L

So at 50 wh/mile, the hypothetical EV would use only 31% of the energy per mile of travel as the original 1L, even though it's 750 pounds heavier(Mind you, this efficiency calculation is from the energy storage medium on board the vehicle, not well to wheels efficiency).
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Old 04-22-2006, 02:25 AM   #20
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Re: Would the defense/aerospace

Quote:
Originally Posted by The Toecutter
To accelerate from 0-60 at a modest pace to reflect typical driving habits, say, 25 seconds over a 1/4 mile distance, a 1,400 pound car would need roughly 17 kW of constant power over that interval. 17 kW for 25 seconds is using .118 kWh of energy for each acceleration from 0-60 mph.

Or, 1.3% of the energy stored in the battery pack for each run from 0-60. This is by no means crippling on range, provided you're driving like normal instead of with a lead foot.
More like .3kwh if you accelerate at 1000 amps for about 5 seconds and accelerating slowly only saves some I squared R losses and a little pertek losses - you stillllll need the same total energy. This is not an ICE powered that burns fuel less efficiently at high power outputs.

Your diesel analysis is very good however arriving at 31% efficiency which is what efficient ICE engines can achieve but what you neglect is the extra energy of combustion of diesel is given off as heat that can be used to keep you warm in the colder months which you are not getting as much of in an electric vehicle.

I however prefer to use the concept we are talking about but on a smaller scale and build a 2 wheel composite enclosed vehicle and be ready for the better batteries when then arrive. I also have the fiberglass, carbon fiber and epoxy materials along with motors and controllers and just need a lot of time to get started building.
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