evnow wrote:My question is - why is that avg speed non-negotiable ?
Do you mean why I can't just take the calculation at an average speed? Well, for the most part an average speed is good, but technically, from my research, your main drag -- if you'll pardon the pun -- is air resistance which is proportional to the square of the speed of the car. That means that if it takes x
watts to go 45 mph, it may take 2x
watts to go 60 mph and then 4x
watts to go 75 mph, as a rough calculation. Now that's the power you need to go that speed. To get the energy draw, you just multiply the power times the amount of time you're exerting that power to get the energy. Hence kWh: kilowatts times hours. For illustration purposes, if you spend 1 second at 45 mph and the next at 75 mph you've basically used 5x
Joules of energy, but if you spent those 2 seconds at a constant speed of 60mph, your energy used is only 4x
. That's why average speed isn't the whole story. That's why EPA LA4 is more complicated than just 19.6 mph: it's really the sum of the intervals from second 1 to 1370, over a minute of which is idle and another nearly 2 minutes are at highway speeds.
However, if the Power Curve of the Nissan Leaf is known or reasonably estimated, we could calculate the expected range of the LEAF under HWFET or EPA75 or US06 or under any other custom, well-defined regime. And with 3 points, e.g. 45 mph, LA4 and 60 mph, it should just be possible to tease out that quadratic power curve equation...
RIP CO2 Fre
, 27 months, 42,282 mi & 11 bars.
unAmerican Job & Nissan's Rapid Depreciation cost $20,000!
on the road daily w/o Charge at Work
Long Live CO2 Fre
, Maxed 2013 SL, 20,000 mi/yr lease.
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