I used to drive the Leaf downhill (from altitude of 130 m to 10 m) from home, and would reset the m/kWh when leaving. At the bottom of the hill, about 2 km from home, if I had been careful driving and wasn't using any climate, I got 99 m/kWh multiple times.
That makes sense, with just two digits before the decimal point, and no sign. Plus some people might get confused on seeing a negative number there.
Cool. There's a small singularity at 0 mi/kWh, right? Approaching from +0.1 mi/kWh, we're driving spectacularly inefficiently, while approaching from -0.1 mi/kWh we're putting 10 kWh into the battery per mile. I think I understand Wh/mi a bit better now, as it doesn't suffer this inverted weirdness. More energy per unit distance is always larger, less power per unit distance is always lower, even into the negatives.bobkart wrote: ↑Tue Jan 26, 2021 9:55 pmThat makes sense, with just two digits before the decimal point, and no sign. Plus some people might get confused on seeing a negative number there.
At first blush, a negative efficiency number seems like a bad thing. But technically, miles-per-kilowatt-hour can be negative, with lower (in absolute-value) readings being better (more efficient) than higher ones. I.e. -4mi / kWh is better than -5mi / kWh. To help myself understand why that is, I'll phrase it as 'it takes four miles of driving to put one kilowatt-hour back into the battery', which is better than needing five miles to do it. Probably moving the minus sign into the denominator would help, because that what's gone negative, as opposed to the miles: 4mi / -kWh.
It's when total energy consumption is zero that you get infinite miles-per-kilowatt-hours (assuming nonzero distance travelled).
I think I see what you're saying . . . 'inefficiency' is infinite at 0mi/kWh (energy is being consumed but no distance being travelled).
I reset mine daily so nothing extreme although one day heading west from my old place (150 feet elevation drop in just under 2 miles) I hit around 15 miles/kwh.bobkart wrote: ↑Mon Jan 25, 2021 3:43 pmI'm sure some have seen higher readings, but I usually accumulate them for a month, so I've never seen anything much over 5.0.
In this case I had a problem that caused my stats to reset, at a charging location that's mostly uphill from home. So this reading was captured on the way back home (at a red light).
This makes me wonder what the reading would be for an all-downhill trip, one that ended up adding to the SOC. Would it report a negative miles-per-kilowatt-hour number? (I.e. ten miles 'using' negative one kilowatt-hour, that ratio is -10.)
I would think that high-enough levels of regen would make the net energy flow out of the battery be negative. I know I had a much higher SOC at the bottom of Hurricane Ridge than I had at the top.