GM Volt Forum banner

3.5 Years worth of OnStar Data Comparing temperature vs kWh/100 miles

6K views 14 replies 9 participants last post by  ari_c 
#1 ·


OnStar data is harvested from the monthly diagnostic emails. Average monthly temperature comes from The Capital Weather Gang of the Washington Post which posts the average monthly temperature for National Airport.

I only drive locally, rarely use climate control. So, any differences can be attributed just to temperature changes. I have gotten more efficient with my driving after year one. This can be attributed to three things.
1) raising the PSI eventually to 50 in my tires.
2) extensive use of neutral
3) becoming more obsessed with getting a "good grade" in the monthly emails :)
 
See less See more
1
#2 ·
Just asking for clarification by a non-VOLT driver. Is the kWh/miles based on the electricity from the wall, which includes inefficiency from the inverter pumps, etc? Or is it based on the energy in the traction battery?
 
#3 ·
My last few monthly diagnostic emails have not included the kWh/100 miles. Just lists ---. Anyone else seeing this?
 
#5 ·
Dennis mine disappeared from November through April. This last one was the first one to have the kWh / 100 miles again. I just went to the myvolt website to get the figure.

Not sure how difficult it is to populate all the fields, but I guess that is too much to ask of OnStar!

Just asking for clarification by a non-VOLT driver. Is the kWh/miles based on the electricity from the wall, which includes inefficiency from the inverter pumps, etc? Or is it based on the energy in the traction battery?
I believe the OnStar figure of kWh/100 miles includes any charging losses.
 
#4 · (Edited)
Thanks for sharing, definitely about a 30% drop in cold weather. It has been warm here so I have been able to regularly get 4.2 kW/mi or better now that the temperature is up, but in the winter it is sometimes less than 2 (heavy heater usage and average temp around 22 F in winter). I think those correspond to 23 to 50 range.

I am curious to see how Volt 2 does with similar temperature drop; see if the chemistry is any better in the cold.
 
#6 ·
...
I am curious to see how Volt 2 does with similar temperature drop; see if the chemistry is any better in the cold.
There is very little a chemistry could do.
All cars loose about 20% efficiency just due to physics. It takes more energy to push a car through cold air than warm air.
Likewise there is more rolling resistance on roads with snow on them.
Most EVs loose about an extra 10%. With cars like the Volt, with a good battery management system, some additional energy is lost when heating the battery pack.
With those without, some more efficiency is lost due to the batteries operating at colder temps, but less energy is lost to heating the pack. Frankly, purely from an efficiency point of view, I am not sure if one is better than the other.
 
#12 ·
Thanks. I was very skeptical of the 20% claim.

With the sports car...well MPG doesn't really matter. It is not the point of the car. I used to track it out of curiosity and it seemed fairly consistent. But I did not plot it or track it all that closely.

The Prius is my wife's car. I keep an eye on what kind of MPG I get but she introduces too many variables. Plus she does not drive in a manner that takes into account achieving good gas mileage.

The Volt is replacing the Prius. It will be interesting to see how it does battery range wise on her commute.

As for the question on Forced Induction. Yes, turbo or supercharged.
 
#13 ·
Thanks. I was very skeptical of the 20% claim.

With the sports car...well MPG doesn't really matter. It is not the point of the car. I used to track it out of curiosity and it seemed fairly consistent. But I did not plot it or track it all that closely.
...
I understand, I was rather surprised myself when I first started paying attention.
Our former Prius averaged 52 mpg in the summer, and 42 mpg in the winter.
As long as it is the same drivers, the change should still be valid. If you drove in the summer and your wife in the winter, that would throw things off.

We replaced one of our Prii with a Volt as well. It was, for us, a great move, we enjoyed the Volt quite a bit.
 
#14 ·
This is the data viewed a little differently

Red Dots are the data points from the first year
Green Dots are the remaining data points
Blue Bars are the average of the green dots for the temperature range covered.
Green Line is an Excel generated trendline of the green dots.


Text Line Plot Pattern Diagram
 
#15 ·
This is the data viewed a little differently

Red Dots are the data points from the first year
Green Dots are the remaining data points
Blue Bars are the average of the green dots for the temperature range covered.
Green Line is an Excel generated trendline of the green dots.
Very cool. Nicely done!
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top