Question about voltstats data

[drbruns]

After a few days of volt ownership, I used voltstats to download my car data. I received the car from the dealer with 1.12623 CS miles. For each of the rows below, this number remains constant when I take the Total Miles - EV miles (I tried including them in the table, but I couldn't figure out how to have all the columns line up).

I haven't driven any CS miles which was confirmed by the calculation I described above, So the question is, "why is my gallons burned increasing?" I have never fully depleted the battery. I park in an underground garage at work and at home park in my detached garage, plugged into my Blink charger. The temperature has been in the mid 80s here in Northern Va.

Can anyone explain this?

I am Rocky Volt on voltstats. (the data follows)

LocalTimestamp GallonsBurned
5/26/2012 7:10 0.36271
5/26/2012 1:32 0.36271
5/25/2012 19:09 0.35013
5/25/2012 13:10 0.32047
5/25/2012 7:08 0.30345
5/25/2012 1:13 0.30345
5/24/2012 19:10 0.29771
5/24/2012 13:13 0.21447
5/24/2012 7:05 0.18736
5/24/2012 1:08 0.18736
5/23/2012 19:08 0.18736
5/23/2012 13:10 0.16
5/23/2012 7:05 0.12722
5/23/2012 0:17 0.12722
5/22/2012 19:11 0.12322

[DonC]

No idea. Could be a problem with the numbers being reported by myvolt. It hasn't been the most reliable. I think you can dismiss the possibility that you're actually using any gas. If your engine came on you would definitely know about it!

[tboult]

Couple of threads on this
http://gm-volt.com/forum/showthread....pen-up-the-API
http://gm-volt.com/forum/showthread....r-actual-usage

The gallons burned is computed from lifetime MPG and miles travled. There have been various hypothesis as to why, none of which totally satisfied me. I tried various type of simple offsets, none of them explain it. But I can tell you that it does, eventually, get better in the sense that the percent error is lower.

[drbruns]

Thanks for the reply. I kind of figured as much. With only 140 EV miles and 1.2 CS miles put on by my dealer, my numbers are pretty small and would be more susceptible to rounding errors and such. I can see that a measurement of gas remaining in the tank will vary based upon temperature, fluid expansion, etc, but the column heading is "Gallons Burned", which I would have thought could be a more objective data point.

I will take a closer look at the trip meter display the next time I get into the Volt. I was mainly concerned that I might be burning gas under some conditions and wanted to ensure this was not the case

[tboult]

Thanks for the reply. I kind of figured as much. With only 140 EV miles and 1.2 CS miles put on by my dealer, my numbers are pretty small and would be more susceptible to rounding errors and such. I can see that a measurement of gas remaining in the tank will vary based upon temperature, fluid expansion, etc, but the column heading is "Gallons Burned", which I would have thought could be a more objective data point.

I will take a closer look at the trip meter display the next time I get into the Volt. I was mainly concerned that I might be burning gas under some conditions and wanted to ensure this was not the case

If you look at voltstats GallonsOfGas, that is measuring what is in the tank.. modulo temp volume and slosh issues its more accurate.


I've also seen micro rounding errors when EV miles vs total miles differ by .01 even though I never used the ICE.
Not sure why/how that happens.

[mixedpixel]

I have noticed the same thing. Voltstats has my Volt burning about 0.3 gallons over the past month. As far as I can tell, the engine hasn't come on during that time.