Air density, temperature, and range

[TonyWilliams]

Note 3 should specify BATTERY temperature.

Note 6 covers air density variations with temperature.

Interesting. I was never quite clear on that. My tables aside, that makes note 6 difficult to use for temperature adjustment without a density altitude calculator*. When doing calculations I used it just for the elevation delta, since that's the major factor in my vertical terrain around here.


* And density altitude calculators are difficult to use for a novice, IME.

How would you otherwise identify adjustments for air density with a one or two line note? I've considered changing the adjustment based strictly on air density % instead of density altitude.

Edit: Ok, I went to the first post and actually looked at your data and I like the concept of a simple % +/- of correction, but now we have to turn that into a table that also considers speed to get an ultimate simple correction.

So, 65mph with a +10% increase in air density = XX% value decrease in range
35mph, etc...

 

[TonyWilliams]

Another previous post of mine:

LEAF Cold Effects:

Several issues related to heat affect the LEAF.

1- Cold on the battery reduces CAPACITY, at about 1% loss per 4F degrees of battery temperature below 70F. Therefore, a freezing level battery at 30F will have 10% less capacity. A really cold battery at -10F will have about 20% less capacity. A new condition LEAF battery at 70F contains 21kWh of usable energy.

2- Using the heater will increase energy usage (and therefore reduce economy and range) by easily up to 30%. There are too many variables to predict in advance how much energy you might use with the heater, but we do know that with zero usage, there will be zero impact to range. The best economy in heating is using only minimal defrost (perhaps cracking a window) and using the seat and steering wheel heaters.

3- Cold air is more dense than warm air, and cold tires have more resistance than warm ones. Plan on 1% reduction in range per 1000 feet decrease in "density altitude".

4- Cold weather generally means "contanimated" roadways with snow, standing water, etc. This increases rolling resistance and reduces range. Again, all but impossible to predict the impact in advance, but it can be substantial (20-30% loss of range).

5- Charging times increase substantially with a cold battery.


There is one advantage to cold batteries, and that is that they will last a long time if you don't freeze them at -30C.

 

[johnrhansen]

Yesterday I used less charge for my usual commute than I ever have before. It was about 50 degrees and partly cloudy. The sun kept things warm enough so I did not have to use the heater or the a/c. And my battery temp went to 4 bars for the very first time. I haven't charged in 3 days. My leaf would last forever if conditions were always like this.