PIP & MPG Spreadsheet

I took a look at the spreadsheet and have a few comments.

1. Right now there is no calculation based on metered kWh if available. It seems like no one else is using metered kWh right now, but it is the most accurate way of tracking power since charging losses are otherwise estimated.
2. Charging losses are estimated to be 15%, meaning 85% of the kWh makes it to the battery. The calculation right now is kWh * 1.15, but that is not equivalent. It should either be:
   1. kWh / 0.85
   2. kWh * (1/0.85) ~= kWh * 1.176
3. Misleading calculations. I think the only calculation that is meaningful here is MPGe, otherwise:
   1. EV Miles/kWh, Miles/Gal Equiv, kWh/100mi are all misleading calculations, since EV miles only counts miles in EV mode w/o blending, but kWh counts all electricity used, regardless of mode and blending.
   2. HV MPG is misleading because HV miles includes blended miles.
4. There should be columns for $/kWh and $/gallon and the $/Mile should be based off of this (or default to the national average if this is not available).

 

agreed, agreed and agreed.

edit: I fixed the 1.15->1.176 but think there should be a consensus before anyone deletes or add columns..

 

Being the engineer at heart, I wondered if the Fleet Average is the interesting quantity or the Distribution?
I downloaded the spreadsheet and plotted MPGe vs EV% in Excel.
EV% as a single indicator is nice to glance at how well you are doing.
The graph gives a nice trend. At the center, 40%EV gives about 68 MPGe and MPGe increases 6.1 mpg per 10% EV increase.
Raw MPG vs EV% is not as clean.

The link is to MPGe vs EV%
https://docs.google.com/file/d/0BzIaSDFGSOMHRHZ0anlKWTVtdUU/edit?pli=1.

Still on my 1st tank after 450 miles, I don't have stats to input yet.

csolsen

 

did you hit the links?

 

Thanks for the chart.

To me, fleet average is very interesting, with more participants and more data points this can be developed into a meaningful database from which 'average user' EV/HV ratio, EV and HV efficiencies and composite MPG(e) can be derived.

Congrats for your new ride, enjoy.

 

Thanks.. Curious about your comment about MPGe vs MPG not matching as well.. does not seem intuitive that one should fit better than the other.. both are a transform. I guess it is just that impact on MPG is more non-linear. Another useful feature of MPGe..

 

Ken, does the MPG spreadsheet actually show up in your Google Docs (for example, if you go to http: //docs.google.com, do you see the MPG spreadsheet)? There are a couple ways that may work, but they both depend on whether the MPG spreadsheet is directly shared with you or not.

But Google Drive has an option to sync Google Docs to your PC and there is an open-source app called GDocBackup that may work also. However, neither of them look like they can handle saving/backing up multiple versions (I'm assuming this is something you want to do).

The MPG spreadsheet doesnt appear in my Google Docs. I am able to access it, but its not directly shared with me, which I'm thinking may be the case for everyone?

EDIT: Sorry, I missed the "back on the server" on my first read. However, I'm still curious to know whether the spreadsheet appears in your Google Docs (shared directly with you). After logging in, I was able to make a copy (File -> Make a copy) which made me the owner (of the copy) and therefore showed up in my own Google Docs.

 

I looked at the Google CL scripts that Dr.I suggested and I was thinking we could use a "get" to download the spreadsheet and then an "upload" to send it back to Google Docs, but I dont know if there's a way to rename the file before uploading it. Otherwise, it seems it would overwrite the existing one.

I also tried the File->Make a copy from Google Docs and there's a checkbox to "Also copy document collaborators". I tried that and it looks like it created a copy for me AND a copy for Sriram, but not you.

However, I could just create a copy for myself everyday and then just share them with you, then you could make a copy of them and save them in your own Google Drive/Docs (rather than just sharing my copy) when you get back. That way, you would be able to just keep them on Google Docs, if that is your primary goal?

Longer term, I would like to replace the spreadsheet with something else, but I dont want to get ahead of myself

 

No problem, I'm on it

 

Was checking out the spreadsheet today (looking at it to respond to another thread) and noticed some folks are posting lifetime data in columns H-N (e.g. check out crewdog on line 55). The problem is that the formulae for various estimates presume this is a per-trip estimate, e.g. the HV MPG is using Col N divided by Col D.

Using the existing formulae produces serios errors, e.g. crewdog's 157PG in HV mode, and also impact the overall fleet averages.


Its using D (gallons) rather than I(also gallons) because D is more precise (I truncates). But if people are going to start using Columns H-N for lifetime I think the forumla's should be updated to use I (or maybe the larger of D or I). Just using I is somewhat problematic as other people have not filled in I.. Easy fix seems to be to just add a column for max (D,I) and use that.


If people think that is best I'll update them...


But now I see another problem.. the overal totals (MPGe) Cost per mile and such are also impacted if people have total miles (in B), but not total gallons. I'll have to update multple formulae it seems.

 

I just updated a new fuel up, and I think i entered correctly this time. sorry for the confusion on previous entry. feel free to delete if it's better for the overall spreadsheet.

Bill

 

I have a student starting to work on a paper on PHEVs.. so I wanted to start getting this data in more usable shape for him. I went ahead and made some changes today.. f there are objections to these changes I'll gladly remove them but these seem to me to be proper corrections.

First, I changed 1.15 to 1.176 (as suggested above).

Given people were sometimes putting in "cumulative data" in columns h-N, I added a column that take max of D and I, called it gas and then used that in any computation that also used column N. If people used cumulative data in N, then column I is the gas used. But I did not just use I as it truncates, so for those using per-tank that can be a significant error. With this correction the HV and MPGe are again being computed using the appropriate gas/miles mix (i.e. more"correctly". )

Added a constraint that gallons in column I need to be reported for the computations to include that data.

I don't know how to address the blended issue that ryogajyc reports impacts HV and EV. Anyone know how significant this is? Anyone have any ideas on how to measure that or correct for it?

 

I sent an email to "pb" from Fuelly, describing a method for Fuelly to add "KWH" data to Fuelly, so they could use it to calculate MPGe, using the EPAs formula, I received a reply, that they will look at the data, and consider it. I add the "KWH" consumption at each fillup to the "Notes" field in that Fuelly entry, I then reset my "EV Driving Ratio 1" display..

see the email I sent below:

Hi there,

I just read the thread on tracking KWH for Plug in Vehicles:

http://www.fuelly.com/forum/968/Electricity-kWh-Fuel-Consumption-and-MPGe

I do have some information on this, as I bought a Plug in Prius about 1 month ago.

The PiP tracks KWH usage on the multi information display, and there are 2 separate "EV driving ratio" trackers. I have my #1 tracker setup so every time I fill up with gas, I take a picture of it, and then reset it. My #2 tracker I never reset, and that is tracking my total lifetime KWH, and total lifetime gasoline consumption etc.

What I have been doing with my fuelly account is entering the "KWH" # in the "notes" field each time I fill up my gas tank... because that's also when I reset that statistic as well.
If fuelly had a way to read that notes field, and there was a symbol that represented "KWH", you could use that # that we enter to calculate MPGe, using the EPA formula (which is documented)

this way, just let the users enter their KWH consumption at the same time as they fill up with gasoline. This will work well for vehicles like the Plug in Prius, and the upcoming Ford Energi Plug In, because we only get 11-15 miles/charge on the PiP, and the Energi is supposed to get around 20 miles of EV per charge, so we tend to go the the gas station every 2-3 weeks, depending on our drive cycle. I have only filled up twice, and I have owned the PiP for 1 month, and driven 1325 miles.

I'm not sure the Volt owners would like this, as they tend to hardly ever fill their gas tanks, as they have a 35-50 mile EV range, and many just never need gasoline. So perhaps they could make a "zero" entry for gasoline usage, but put in the KWH consumption in the "notes" field, the same way we could.

I am enclosing a Photobucket link to a picture of the Multi information display "EV Driving Ratio 1" display on my Plug in Prius, from the fillup I just did today, so you can see what information is tracked/availble. You will see I used "87" KWH, and I drove 365 miles in EV, and used 4 gallons of gasoline, driving 257 miles on that, it also shows the EV/HV percentages, I am at %58 EV / %42 HV since the last fill up (2 weeks ago), and If you add the 2 numbers together, I drove 622 total miles, since the last fill up as well, it even has an "estimated fuel saved by charging" #, mine shows as 7.3 Gallons since the last fill up.

"EV DRIVING RATIO 1" (current tank, zeroed at each fillup)


"EV DRIVING RATIO 2" (lifetime, never cleared)


thanks for taking the time to read this, and I hope Fuelly can eventually be updated for Plug In Hybrid vehicle tracking, as the KWH are needed to get a true MPGe for anything that plugs in.

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"pb" from Fuelly's reply;

Thanks for taking the time to share this info, it's very helpful. I've forwarded it on to Matt (my Fuelly partner) and we'll include it in our discussions about adding KWH. I really appreciate it!
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