Vehicle Weight does matter in any vehicle system where you only use energy (fuel) to accelerate the mass, and to decelerate the same mass you convert the energy to heat via friction = brakes - there the potential kinetic energy is 100% wasted on deceleration.
In EV which almost all mfg, even those making golf carts, use regen to brake, very high proportion of the energy can be re-captured in the battery upon braking.
While you can not FAST charge, any battery for extended time, or it overheats, you can put in up to 20 times (in some cases) the current into a battery relatively safely.
So even a Pb acid battery that at most can be charged at 16A can for few seconds take 100A safely.
If the vehicle weight is higher, then small losses like those of tires can be overcome and the down hill travel can also be used very efectively for re-charge.
Light vehicle will stop even on slight downhill, while heavy vehicle will roll, and even can supply power during down hill travel.
That is where the theory of light weight at any cost, is overcome by real life experience where in EV with re-gen the weight not only does not matter but a heavier vehicle actually shows a "benefit" in real life range.
And just to clarify we are referring differences in 100's lbs and not in 1,000 lbs. or 10,000's lbs. In othervise IDENTICAL vehicle.
Mirox, thanks, but am not getting why you had made the statement the curb weight has no effect in power consumption. What I understood is when load is more, the engine consumes more power to pull the load and vice versa. In such cases, am not sure your statements are right.
Range test as per NEV America 20MPH Constant Speed
So the TESLA technology on performance level is nothing "out-of-the-box", just the battery is REALLY BIG (On Capacity), and the fair price for the Battery alone would be today about :
the 24 Miles OKA range is in EPA FTP-75 City Range Test,
the 32 Miles is in NEV America 20 MPH Constant Speed test.
We recommend that for maximum Battery life it is plugged in after 16 to 20 miles of travel, driving the vehicle to "till it does not move" will drastically cut the battery life, especially if that is done often. (Pb Acid Sealed batteries)
As strange as it may seem in REAL LIFE, the curb (CW) weight ABSOLUTELY DOES NOT MATTER !!!
It takes AMPS to accelerate it, and to push it up hills, but once vehicle is in motion it has NO EFFECT, and actually heavier vehicles perform better in STOP and GO as with Re-GEN substantial amount of the energy can be used to re-charge the batteries.
Batteries can take lot of input Current for short periods, but overheat if you would put the same Amps in continually like when re-charging from AC Charger.
So lugging about Pd versus Li makes little or no difference on RANGE, but makes the vehicel cost $$$$ more.
But Pb is just not "sexy" enough, so the "light weight" hype that while TRUE for GASOLINE and NON HYBRID (no braking regen) does save fuel, in EV weight is actually BIG PLUS for range (as much as 25% in properly designed system) for IN CITY Driving, in test on Highway at steady speed there is some small penalty due to extra rolling friction but that is normally in 1.8% range, so not noticeable to consumer, but measurable on dynamometer test. But when as much as 60 to 80% is lost to aerodynamic drag at high speeds the less than 2% is not significiant.
OKA is NEV or Neighborhood Electric Vehicle, that is LOW SPEED (25 MPH Max) as per FMVSS #500
IT was just listed for comparison as we have real life data from their use since 2003 with Lead-Acid Sealed Batteries, no stellar technology and the 4kWh Pack was $702 in 2003 and is $2016 in 2012.
So that also diminishes all the Li proponents that prices will be reduced in 10 years, in case of Pb they have almost trippled !!!
So lot of the "theories" in real life so not pan out, in Li-Ion the 4kWh pack costs over $4,200 and it is only theoretical that it MAY last 2,000 cycles, while on the ancient Pd battery made from PURE Lead with bit of Silver, we get 5 to 7 years of service with daily use of the vehices, averaging about 16.2 miles per day and about 10 miles between plug-ins.
That is real life data from all the OKA owners that bother to keep track of things.
While it take lot of Amperes to accelerate "weight" at below 45 MPH once any vehicle is rolling the power consumption per mile should be about equal on well engineered vehicles. Over 55 MPH the aerodynamic, Cx and frontal Area become more important than the rest or the technical features as far as W/mi.
Mirox, from your chart, it seems that OKA is the one can yield maximum power. So I think it's better to look in an another angle by interconnecting some batteries as a grid for pooling more power for bigger vehicles like Tesla and Leaf.
Charles, what's about a small battery grid inside the EV, which can pooled more power. Another factor to increase the mileages is reducing the curb weight of EV and minimizing the frictional forces within the vehicles.
Tesla Motors’ $35,000, 200-mile electric car may not revolutionize the auto industry by itself, but it could serve as a starting point for a long, steady climb to a day when half of the world’s vehicles will be plug-ins.
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