Chassis CAN Logging To ASCII Text Plus Graphing

[whitex]

MikeBur,

Do you have a comparison of what TACC say at 60mph on flat surface draws with range mode on, vs. range mode off? It would be interesting to compare front vs rear efficiency on the PxxD's.

 

[wk057]

:scared: You mean 2.12.45, right?

Whoops, yeah.

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Wk, what Packconfig and FW ver are you running?

Packconfig shows 70. (Not 70 kWh, some internal number Tesla uses for pack version)

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Here's a graph of what the BMS reported as max power for charge and discharge along with SoC and pack temp from the time I left until my laptop went dead on my way home when the car was at about 50% SoC.

 

[MikeBur]

Nice. Interesting to see how much the temp affects the max discharge rate while you were parked...

What graphing software you using? hoping to tear smac away from his plasma cutter and welder, though fear it's too much fun to see him code anything up soon ;-)

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MikeBur,

Do you have a comparison of what TACC say at 60mph on flat surface draws with range mode on, vs. range mode off? It would be interesting to compare front vs rear efficiency on the PxxD's.

Not consistent enough for before/after upgrade, though would expect similar. I'll just pop out and try this. I have a request from Kenny too, though that may cost me some tire tread....

 

[wk057]

Nice. Interesting to see how much the temp affects the max discharge rate while you were parked...

What graphing software you using? hoping to tear smac away from his plasma cutter and welder, though fear it's too much fun to see him code anything up soon ;-)

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Not consistent enough for before/after upgrade, though would expect similar. I'll just pop out and try this. I have a request from Kenny too, though that may cost me some tire tread....

Google Docs spreadsheet chart, and a screenshot.

 

[whitex]

Whoops, yeah.

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Packconfig shows 70. (Not 70 kWh, some internal number Tesla uses for pack version)

- - - Updated - - -

Here's a graph of what the BMS reported as max power for charge and discharge along with SoC and pack temp from the time I left until my laptop went dead on my way home when the car was at about 50% SoC.

The max discharge slope looks like a linear combination of the SoC slope and the pack temperature slope. Once the pack temp levels off (slope 0) the max discharge rate slope seems to parallel the SoC line. Am I reading this correctly? At 50% SoC but 48 deg the max discharge should be somewhere around 380KW, yes?

 

[MikeBur]

MikeBur,

Do you have a comparison of what TACC say at 60mph on flat surface draws with range mode on, vs. range mode off? It would be interesting to compare front vs rear efficiency on the PxxD's.

Ok, I'm so wishing I had a couple of hours of my life back currently - this was real boring. 1.5 mile section of almost level freeway, loop back round, same 1.5 mile section of freeway, loop back round... and 6 more times... with the climate control off... then come back and plot them

Here's range mode on / off at 70mph: rest are pretty darn similar. Available as MikeBur 02-25-16-RangeModeTests.xlsx on the google drive share.

Only interesting aspect was the interesting pattern on the power data.

Hope this helps, Mike

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@MikeB, by all means keep posting charts of interesting runs and events. If you try the run i mentioned maybe 0-30 is enough, safety first...

Hi @KennyBobby,

I tried 3 times to get some level of traction slip using slip start - no luck. These tires are just too sticky, even at >90% SoC. The 3 attempts I did are in the RangeModeTests xlsx just mentioned above if you want to check out the craziness. wk has a way to turn off traction control on the pXXDs that would be more like what you want, though I believe he likes his tires

 

[kennybobby]

Thanks for trying Mike, i thought it would be interesting to see what a launch looked like without traction control (current, F and R Torques, Voltage, speed) if that was possible. It may be that the peak torque is hard coded, but Jason was able to hit a higher limit.

 

[smac]

Thanks for that Mark.

From the looks of things basically the Model S turns into a front wheel drive car at steady state 70mph. Be interesting to see if this is true at lower speeds too, or there is an efficiency crossover between the two motors at a certain speed.

A drive using TACC at 10, 20, 30, 40, 50, 60 for a minute at each would prove / disprove this theory.

My hypothesis is that the front motor under steady state is always more efficient, and the rear motor is primarily there for acceleration. Would be interesting to see if this is also true for the 85D too.

 

[lolachampcar]

Wow, this is what I get for stepping away one evening to have dinner with my wife

Wk,
I've been using the measured torque messages instead of estimated torque which could explain the difference in torque values between your car and data from my logger. Is there a reason you went with one versus the other?

Brian,
I bought ten diag cables with the idea of having ten loggers in circulation. I suspected that most would want to collect and understand data from their car then really have no long term need for a logger. That person could then ship it to the next interested owner to enable evaluating their car. If you like, I can get one to you for your testing; it would just be a loaner and not a long term thing.

On a different note, I've noticed that the CAN traffic on my wife's S85 is not as robust or time aligned as on my P85D. This might explain the time shift for current versus torque on one the above plots (where torque leads current - not realistic unless Tesla is really really good).

Lastly, I really love that 10 msec time constant traction control event on the P85+ Neat stuff. Actually, I just looked at it again and it appears to be 7 iterations in a 1/2 second.

 

[MikeBur]

Thanks for that Mark.

From the looks of things basically the Model S turns into a front wheel drive car at steady state 70mph. Be interesting to see if this is true at lower speeds too, or there is an efficiency crossover between the two motors at a certain speed.

A drive using TACC at 10, 20, 30, 40, 50, 60 for a minute at each would prove / disprove this theory.

My hypothesis is that the front motor under steady state is always more efficient, and the rear motor is primarily there for acceleration. Would be interesting to see if this is also true for the 85D too.

i want to say, you're welcome... Though did you really mean Mark? ;-)

Definitely worth also looking at Chassis CAN Logging To ASCII Text Plus Graphing - Page 24, as it shows even under minimal acceleration conditions the front motor is preferred. I won't have ability to do any more until Monday now.

 

[MarcG]

i want to say, you're welcome... Though did you really mean Mark? ;-)

Don't feel bad, I get the reverse pretty often (people calling me Mike). Marc, Mark, Mike, it's all the same right? :biggrin:

Thanks for taking 2 hours out of your life to get us some good data. Interesting that range mode doesn't seem to have an effect on the torque distribution, but perhaps at lower speeds?

(PS: tried to give you more rep points but need to share the love elsewhere first...)

 

[wk057]

I've been using the measured torque messages instead of estimated torque which could explain the difference in torque values between your car and data from my logger. Is there a reason you went with one versus the other?

That could explain things. I just grepped my output variables for "torque" and just grabbed those two. My parser decodes something like 500 variables now (mostly error codes), so the "PM" prefixed ones (where "measured" torque is) were no where near the "DI" prefixed ones in the list.

 

[whitex]

Ok, I'm so wishing I had a couple of hours of my life back currently - this was real boring. 1.5 mile section of almost level freeway, loop back round, same 1.5 mile section of freeway, loop back round... and 6 more times... with the climate control off... then come back and plot them

Here's range mode on / off at 70mph: rest are pretty darn similar. Available as MikeBur 02-25-16-RangeModeTests.xlsx on the google drive share.

View attachment 112782

View attachment 112783

Only interesting aspect was the interesting pattern on the power data.

Hope this helps, Mike

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Hi @KennyBobby,

I tried 3 times to get some level of traction slip using slip start - no luck. These tires are just too sticky, even at >90% SoC. The 3 attempts I did are in the RangeModeTests xlsx just mentioned above if you want to check out the craziness. wk has a way to turn off traction control on the pXXDs that would be more like what you want, though I believe he likes his tires

Thanks for the data Mike! It does appear that the car already sleeps the rear motor at cruising speeds, meaning range mode may not increase range for long highway trips, unless it somehow limits HVAC heating or cooling.

 

[AWDtsla]

Thanks for the data Mike! It does appear that the car already sleeps the rear motor at cruising speeds, meaning range mode may not increase range for long highway trips, unless it somehow limits HVAC heating or cooling.

They've obviously been making some changes. You can tell just by the sound of the motors. If they can wake/sleep the motors fast enough, there's 0 need for a "range mode" button. In this case they could just rename it to "make the thermostat ineffective mode"

 

[MikeBur]

Don't feel bad, I get the reverse pretty often (people calling me Mike). Marc, Mark, Mike, it's all the same right? :biggrin:

Thanks for taking 2 hours out of your life to get us some good data. Interesting that range mode doesn't seem to have an effect on the torque distribution, but perhaps at lower speeds?

(PS: tried to give you more rep points but need to share the love elsewhere first...)

LOL, thanks Marc/Mark/Mike* ;-)

Definitely appears to be more actively using front motor when between 30-50 in range mode vs. not - you can literally hear the front motor on/off with range on/off as you drive. The range graphs here http://www.teslamotorsclub.com/show...lus-Graphing?p=1388038&viewfull=1#post1388038 show this, though I don't have time this side of Monday to pull a similar run (likely tail end of an existing insane run) to compare better. Of course, if no one has done this by Monday I'll do a comparison.

 

[MarcG]

you can literally hear the front motor on/off with range on/off as you drive

Wouldn't it be the rear motor that turns off with range mode on?

 

[brianman]

Wouldn't it be the rear motor that turns off with range mode on?

That's my understanding as well -- for both P*D and *D.

 

[MarcG]

That's my understanding as well -- for both P*D and *D.

Actually for non-P dual-motor models, I believe Tesla stated either motor can be put to "torque sleep" depending on the situation, since they're essentially the same motor so should have the same efficient at the shaft level (not sure how they're geared however).

 

[wk057]

I found a CAN ID for longitudinal and lateral acceleration measurements......... unfortunately it's on the chassis CAN bus and not the power train CAN.

 

[brianman]

Actually for non-P dual-motor models, I believe Tesla stated either motor can be put to "torque sleep" depending on the situation, since they're essentially the same motor so should have the same efficient at the shaft level (not sure how they're geared however).

Clarification:
My impression is that currently the front never turns off. That's not in conflict with what you've said here.