edatoakrun said:
TonyWilliams said:
...The only limitation is that the CarWings data will always be extrapolated to determine useful battery capacity, unless the car was run all the way to dead...
As with any other method. That is precisely why I suggest those who do discharge past VLB, check their CW report of kWh use, to see if this will accurately determine total available capacity, at different temperatures.
How would the CarWings kWh report from any previous trip (assuming its accurate, and that you have whichever firmware update that makes it accurate) be different than dividing miles/kWh from the dash into odometer miles driven?
This is the best method you now have, but there may be a better way.
The LEAF gives two different m/kWh readouts, both rounded to the nearest 0.1 m/kWh.
It is entirely possible that CW will give more precise results, and also can tell you which vehicle readout is correct.
Actually, that's the first logic test that I would apply to CarWings data. If the data differs between the two, I would continue to think CW to be inaccurate, as it is with it's 2.5% mileage error, even post update. However, if they do match, I merely have another source of the same info.
The way that you appear to be using the data, with historical perspective, seems reasonable. The data wouldn't even have to be accurate, just indexed properly to provide a reference for identical trips in different conditions.
TonyWilliams
...Secondly, CarWings kWh data can serve little useful purpose in estimating the capacity of a trip not yet taken
I disagree.
Knowing total available battery capacity in advance allows you to plan trips, and adjust your route, speed and CC use accordingly, to avoid extremely low SOC, or even "dead" conditions.
While i agree with your statement as stated, I don't agree with the premise. I've been doing exactly what you're suggesting for 17,000 miles without once referencing CarWings for critical info.
Sorry, but you don't know what you're missing, so you are unable to make the comparison.
have made many trips (including both those I referenced above) that exceed the maximum range that your chart predicts. This is mostly due to a higher ratio of ascent energy recovery I have seen, about 80% rather than the 50%, on your chart.
Regen is tough. I haven't spent much energy developing a list of parameters to determine what your regen might provide. I'm sure you'll agree that if I started at the top of a mountain with 100% charge, I will get precisely ZERO regen going down the hill.
Also, if the battery is cold, the regen can be severely limited. Finally, if I hit the brake with too much vigor, or hit a big bump, the regen is immediately reduced and hydraulic brakes are increased.
So, at least three major factors affect regen; High SOC, battery temperature, and brake pedal use. Minor factors are things like ECO or D mode, amongst others.
I don't believe that the entire regen and reuse of that regen'd power is 80%, even in the most advantageous circumstances, but even if it is, there are too many scenarios where it is close to zero.
Therefore, until logical data can be collected for all conditions, and a logical way to present the data for its use, 50% regen efficiency is the best middle ground I can come up with for now.
I expect it would be nearly impossible to get a ratio of 50% or lower on any public road, under the most adverse conditions.
The majority of ascent energy is recovered WITHOUT the use of regen at all. In many circumstances, roads are graded to allow you almost 100% recovery, which is the case whenever you coast or apply energy to increase your speed on a descent, rather than accept energy back into the battery using regen to arrest your speed.
CW regen reports are a good place for you to look for more on this...
But the relatively minor reduction in available battery capacity down to about 25 F
We would have to qualify what minor is, but the data will bare out something. One thing that I hope is that the data is at least linear!
Again, to those in extremely cold climates, please help us gather data ! See my thread for Free T-shirt !!! Please volunteer a bit of your time to help provide cold weather data
here, "Wanted: Extreme Cold Weather Range Data".