For other data geeks like me, I wanted to share what I've learned about temperature and range in the Fisker Karma.
We know we lose range when it gets cold, but I wanted to know by how much. I also wanted to know if we lose range as it gets really hot. I am sure a Fisker Engineer worked this out in a simulator, but I wanted to get real-world measures. I logged my travel to a fixed point from my house, and back... I wanted to see where the sweet spot of maximum range, and what happens when it gets hot, cold, etc. Since I live in the mountains, to airport is a drop of about 2000 feet, and home is back up the hill. Merging the too gives a good estimate of the % range gained/lost in relationship to temperature. The range of temperature is from 20 degrees to 98 degrees. (-7 to 38 Celsius).
My data is below. The sweet spot of maximum range is 75 to 85 degrees (24 to 29 Celsius).
The variability is how fast I was driving -- sometimes I am running late to the airport, and I've shared previously the relationship between e-range and speed. As one exceeds 65mph, range drops a lot. There is also a little bit of noise in my temperature measurement range from where I live and where I was traveling to (I used one number roughly in the middle of the range). That said, for a basic model that leaves out my speed, temperature alone explains a lot of the variation in electric range. It would be cool if the Karma computer sensed the temperature and used it in the algorithm for estimating the range (rather than using the fixed 50miles so we had a realistic projection).
I posted the data chart on the newfisker site.
Two other things I am interested in... 1) what is the magic number at which our range flips from 409 to 0... since it picks up again and starts counting. (I think it is 455.5miles - but plan to refuel and start the counter and double-check.)
The other thing I am interested in is whether we lose range as the battery is used. But that is a slow process as I am only at 23k miles. So if someone else has been logging their miles to and from a fixed point, and noting the temperature, they might get to an answer faster than I do. If so, keep us posted.
If anyone else is a data geek, and already unlocked these mysteries, share what you've learned please. I'm always curious about what we can learn from measurement. (It's an occupational hazard).
We know we lose range when it gets cold, but I wanted to know by how much. I also wanted to know if we lose range as it gets really hot. I am sure a Fisker Engineer worked this out in a simulator, but I wanted to get real-world measures. I logged my travel to a fixed point from my house, and back... I wanted to see where the sweet spot of maximum range, and what happens when it gets hot, cold, etc. Since I live in the mountains, to airport is a drop of about 2000 feet, and home is back up the hill. Merging the too gives a good estimate of the % range gained/lost in relationship to temperature. The range of temperature is from 20 degrees to 98 degrees. (-7 to 38 Celsius).
My data is below. The sweet spot of maximum range is 75 to 85 degrees (24 to 29 Celsius).
The variability is how fast I was driving -- sometimes I am running late to the airport, and I've shared previously the relationship between e-range and speed. As one exceeds 65mph, range drops a lot. There is also a little bit of noise in my temperature measurement range from where I live and where I was traveling to (I used one number roughly in the middle of the range). That said, for a basic model that leaves out my speed, temperature alone explains a lot of the variation in electric range. It would be cool if the Karma computer sensed the temperature and used it in the algorithm for estimating the range (rather than using the fixed 50miles so we had a realistic projection).
I posted the data chart on the newfisker site.
Two other things I am interested in... 1) what is the magic number at which our range flips from 409 to 0... since it picks up again and starts counting. (I think it is 455.5miles - but plan to refuel and start the counter and double-check.)
The other thing I am interested in is whether we lose range as the battery is used. But that is a slow process as I am only at 23k miles. So if someone else has been logging their miles to and from a fixed point, and noting the temperature, they might get to an answer faster than I do. If so, keep us posted.
If anyone else is a data geek, and already unlocked these mysteries, share what you've learned please. I'm always curious about what we can learn from measurement. (It's an occupational hazard).
