klapauzius wrote:I wonder if that ever has been corroborated by a real scientific study? While the range estimation is not very accurate at high levels of charge, once you have driven the car a bit, it becomes in my subjective (n-of-one) experience, quite accurate.
Again with automatic logging (or even pen and paper) it should be trivial to sum up actual miles driven + DTE and check how constant these numbers are over the length of the trip. If we do that across e.g. 100 drivers in different locations, we can easily compute a confidence level for the GOM and conclude if it is really dog-doo-doo or the innocent victim of prejudice...
I'm not sure if this qualifies as a scientific study, but as I've mentioned here and elsewhere, I have done fairly extensive range testing for the reverse SOC meter
project. To be honest with you, I was also getting tired of the constant second-guessing and kibitzing by folks that have rarely, if ever, driven their Leaf to turtle (and beyond). Tony has led the charge on this front, and I trust his judgement. He has been nothing but methodical. I have several hundred data points as well, and although I don't have much time for the requisite postprocessing, I can assure you that the GOM is borderline unusable. It consistently overestimates the total range by 15 to 30% on a full charge, and it underestimates the true range by up to 50% as you approach the low battery warning. It's fairly accurate in the middle of the range, which demonstrates that it can work too, but it fails to do so on either end of the SOC range. This was measured over several full battery cycles, with consistent driving and weather patterns on flat roads. In other words, ideal conditions.
I don't expect miracles, just something that works reasonably well, or I can configure to make work reasonably well for my needs. If Nissan allowed me to insert an energy economy factor that would be multiplied by the estimated available energy, I could stop doing the mental math. I would not mind if the vehicle used an aggregate m/kWh factor, the one that's displayed on the dash for example, which would get reset every time I reset the gauge. That way, I would have control over the integration interval. It could be minutes, hours, days, weeks, moths or even the life of the vehicle.
Speaking of which, I think that it's insane for Nissan, BMW, or any other manufacturer, to adjust the full range prediction based on a few seconds of driving. Absolutely insane. You get erratic behavior like we all know too well from the Leaf, or like I saw in the ActiveE this morning. My total range estimate jumped from 150 miles to 190 miles after a few seconds of regen. Seriously? The range prediction should be fairly consistent, constant, and based on a longer time interval. Hours, days even. If you wanted to alert the driver that current road conditions or driving patterns will severely impact range, you could show a message or an alert, much like we see with A/C in the Leaf: if you keep driving like this, your total range will decrease (or increase) by XX miles.
Basically, you would work with two range estimates, one based on a medium to long-term integration period, and another one based on a short-term integration period. You would display the more constant of the two figures, and the delta. If you cared to achieve the projected range, you would want to keep the delta close to zero. Likewise, if you were running low, and needed to conserve energy, you would want to keep the delta in positive territory.
Wouldn't that be good enough?