Speed vs. Power Gauge: Request for Data

[JoeS]

... For example, repeated runs in the very early windless morning on the flattest road I could find resulted in a speed of 22mph with the needle sitting right on the bottom edge of the green zone....

iMiEVNZ7, this is the reading with the needle right on the edge of the green, NOT halfway between green and blue. Halfay between green and blue is the zero power point, and it is amazing how slowly the car slows down at lower speeds when simply coasting (leading one to believe power is still being applied).

WeeJohn, thanks again for your numbers. Corroborates mine quite well. Now, all we need is a few more datapoints to do a regression analysis and come up with a speed vs. power graph.

 

[JoeS]

In this thread I had hoped to quantify the energy consumption vs. speed of our iMiEV. Unfortunately, this necessitates an absolutely flat (without even tiny undulations) completely windless road (known altitude and temperature) with zero traffic ahead (so as not to disturb the airflow). Guess what? Such an animal doesn't exist in my part of the world, and I've basically abandoned this quest, especially since anything over the first tick mark gets us over the legal maximum speed limit (… except in Texas?). If any of you have these 'ideal' conditions, I'll still welcome your data - just send me a PM… and I'll try to plot the results. Thank you to those of you who have already contributed.

 

[DonDakin]

Hi JoeS,

I just read this thread as it became active with your last post. I remember reading a thread on here about sniffing the can bus in the car and datalogging it. I would think that would be that best way to get accurate data for battery amps vs speed. I guess if you could also get gps data then you could get elevation and that would be a good way get the cars parameters and maybe derive an accurate model of the car. Not everyone has this kind of equipment but I'm sure if you look for it you could find it.

Personally when the weather is good and I'm in no hurry and there is no traffic I'm sure I could get 100 miles out of the i but I have to admit that would be driving it in a really unrealistic "lab only" way. I call it "Driving under the E".

It is kind of interesting to think that if you wanted to meander around and could find a quick charger at 100 mile intervals you could cover 200 miles in about 8 hours of driving in an i. Not exactly an automotive breakthrough given traditional thinking but still an accomplishment to go 200 miles for $1.60 (Quebec has really cheap electricity and expensive gas ($0.05 /KHW and $1.35 /liter).

Let us know what you come up with.

Don.....

 

[JoeS]

DonDakin, I am looking forward to the time when our CAN BUS sleuths have an iMiEV version ready for us - datalogging of these two parameters (power and speed) would be great for this project. As I'm sure everyone has noticed, this data would have to be accompanied by the ability to define the conditions as one drives (voice recorder?) because even small undulations in the roadway or slight headwind/tailwind/traffic can significantly alter the readings.

 

[marlon]

Concerning the power gauge, I contacted Mitsubishi. They weren't very helpful but it did tell me that I don't think we know what the guage measures. Here is their response:

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Thank you for your email to the Mitsubishi Motors Customer Relations Call Center regarding your power meter inquiry for the Mitsubishi i-MiEV.

The power meter located in the center of the dashboard of the i-MiEV consists of several components and has a red needle that is driven by communication from an on-board Engine Control Unit (ECU). The meter is only an indication to the driver, as to relative power consumption or power regeneration which is occurring while driving the vehicle.

If the needle is in on the charge side of the meter, power is being driven back into the 330V battery and alternatively, if the needle is on the ECO side of the meter power is being consumed by a combination of the electric motor, air conditioner, heater, etc. The further the needle travels to the right side the more power which is being consumed. The further the needle travels to the left side the more regeneration of power is occurring.

The meter is a power meter and is not calibrated to be able to tell a driver how much power is being generated or consumed, and is nothing other than an indication of power usage and generation.

We trust this information is useful in addressing your inquiry and thank you again for this opportunity to respond.

Sincerely,

Customer Relations Department
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We enthusiasts are their best promotion. I think we are entitled to a little more real information about the car. I don't think telling us something about the guage is going to violate any trade secrets. If we know more about the i-miev it makes it more fun. And lets face it, as of today, no one buys this car just to save money. You have to see the excitement in driving an electric egg. Otherwise, we'd all be driving camrys and civics.

Marlon

 

[Don]

Concerning the power gauge, I contacted Mitsubishi. They weren't very helpful but it did tell me that I don't think we know what the guage measures. Here is their response:

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The meter is a power meter . . . .

Well, at least they told us what it's measuring - It's not just amps . . . . it's watts

Don

 

[GdB]

I'm looking seriously to buy an i-Miev as a 2nd car to share with my wife. It compliments my VW TDI mega range.

So I put together a spreadsheet which correctly calculates range versus speed, and has other nice related info also...

I was going to attach it but I found this in the FAQ:
"Why can’t I add attachments?
Attachment permissions are granted on a per forum, per group, or per user basis. The board administrator may not have allowed attachments to be added for the specific forum you are posting in, or perhaps only certain groups can post attachments. Contact the board administrator if you are unsure about why you are unable to add attachments."

 

[PV1]

Welcome to the Forum.

For attaching pictures, we rely on 3rd party sites to link a URL back here, such as Dropbox. If there are options to enable attachments, please enable or direct us to where we can attach files.

As to your looking at the i-MiEV, what are your daily range requirements and driving conditions? Meanwhile, maybe someone more familiar with the forum's function can help with posting your data.

 

[JoeS]

...So I put together a spreadsheet which correctly calculates range versus speed, and has other nice related info also...

GdB, welcome to the forum. We'd sure be interested in seeing your spreadsheet.

One way of doing it is to save it as a PDF file or even a jpeg image and, as PV1 mentioned, put in on a web-accessible site and post the link to it within "Img" brackets. We had a discussion about posting on this thread: http://myimiev.com/forum/viewtopic.php?f=13&t=1626&start=0 , and maybe someone can update it?

Incidentally, this thread is pretty well obsolete with the advent of CaniOn. Also, the latest hypothetical curves are posted here:

http://myimiev.com/forum/viewtopic.php?p=17565#p17565

 

[GdB]

I matched test data without including coulombic efficiency.

Also I assumed no auxiliary power as in the equations here:
https://www.desmos.com/calculator/8bfswqy3rm

So I match the link you provided except at low speeds I don't due to ignoring auxiliary power.

My spreadsheet is easy to modify parameters as I have already done with a few studies...

I'll post a wetransfer.com link in a few hours .

 

[JoeS]

I moved GdB's excellent post over to the iChart thread: http://myimiev.com/forum/viewtopic.php?p=18199#p18199

Shutting down this thread because, now that we have CaniOn, it is no longer relevant.