Roadster Sport RED vs WHITE Performance modes

[scott451]

I've received a number of PM/emails about the performance of the roadster Sport and recent firmware changes. I did some data collecting on a friends sport and here's what I found:


Do I have to be in performance mode to get the max out of my Roadster Sport? Yes. The torque in Standard mode is limited to 265 ft-lbs vs 295 ft-lbs in performance. (see plot below)

http://www.teslamotorsclub.com/attachment.php?attachmentid=985&d=1282720654


What does it mean when the 'Performance' on the VDS changes from white to red? Do I lose power? Yes. When VDS 'Performance' turns red, the PEM temp is >= 45C and the max torque is limited to 273 ft-lbs. When 'Performance' is white, the max torque is 295 ft-lbs. The good news is that the PEM fan is very powerful and it cools the PEM down in about 30 seconds. (@26C ambient. YMMV)

http://www.teslamotorsclub.com/attachment.php?attachmentid=983&d=1282720649

When the PEM temperature reaches 45C, the max torque will be limited to 273 ft-lbs

http://www.teslamotorsclub.com/attachment.php?attachmentid=982&d=1282720648


VDS 'Performance' is red, but the PEM temp is only on the last blue bar. In the new firmware, the last blue bar is on for PEM temps 43C to 60C.


I recently got a firmware upgrade. The bars on the VDS temperature screen seem to act differently. This screen has changed how the battery temperature is displayed. Attached is the data from my 2008 roadster. (I have also checked it against a recent roadster sport VDS )

http://www.teslamotorsclub.com/attachment.php?attachmentid=986&d=1282721159

Disclaimer: My conclusions & data could be wrong. I don't work for Tesla nor have any friends that do. I'm just passionate about Tesla's products and understanding how they work. The data is the result of my own analysis of my roadster and discussions with (and log data from) other owners.

[raymond]

Scott, thanks for the info! I've actually been looking around for these figure quite a while hoping Tesla would provide these one day.
Now about performance mode: firrst I thought it would simple dial in higher limits for e.g. motor current, but later I heard that charging in performance mode pre-heats the batteries. Does this mean that warm batteries have a higher power discharge (at the cost of shorter life span)? If so, you would need to select performance mode some times before you actually get maximum performance.
Any thoughts on this?

[bolosky]

What instrumentation did you use to get that data?

I'd love to see comparable graphs for the other Roadster models (2008, 2010 non-Sport, Roadster 2.5 if it's any different from 2.0; I just heard that the 2.5 PEM has hi-temp chips that allow it to run much hotter).

It's also interesting that a hot PEM is limiting torque rather than power. My experience with getting Roadsters toasty is that when the motor is hot it limits torque but the PEM limits power. Maybe it's different for the lower temps you're dealing with; I'm thinking of when you get all the way to red and the warning comes up on the VDS.

[DrTaras]

Scott- This is awesome! You have answered so many questions and so succinctly! I don't doubt your data crunching ability at all, but one thing I know for sure... I validate what you said: "I'm just passionate about Tesla's products and understanding how they work." Thank YOU! :-)

[scott451]

Now about performance mode: first I thought it would simple dial in higher limits for e.g. motor current, but later I heard that charging in performance mode pre-heats the batteries.

I don't think that the battery is "heated" in performance mode. The only time I have seen a heat record in a logfile is during charging when the battery very cold. In performance mode, the battery is allowed to run hotter. [update 11/2010] It appears that cooling is reduced when charging in "performance" mode. So the battery will be hotter when fully charged.



Does this mean that warm batteries have a higher power [output] (at the cost of shorter life span)? If so, you would need to select performance mode some times before you actually get maximum performance?
Yes (see graph below). The curve shows that for the same current, at a higher temp, the output voltage is higher so the total output power is higher. For max power, you get diminishing returns for temperatures over 45*C. And No, I haven't noticed any delay selecting performance.

http://www.teslamotorsclub.com/attachment.php?attachmentid=987&d=1282846484

[scott451]

It's also interesting that a hot PEM is limiting torque rather than power.

Actually, it's the motor current that matters. I didn't plot it, because the motor current is correlated to the torque (and it's easier to get torque from the VDS). It really comes down to how much current you can pump out of the PEM without overheating it.



My experience with getting Roadsters toasty is that when the motor is hot it limits torque but the PEM limits power. Maybe it's different for the lower temps you're dealing with; I'm thinking of when you get all the way to red and the warning comes up on the VDS.
I would describe it as a "warm" PEM is limiting peak power by 7.5%. A hot PEM limits the power a lot more. Tesla is taking advantage of the thermal mass (WattSecond/degC) of the PEM heatsink to dump peak power into a warm/cool heatskink, which would normally overheat a hot heatsink. It's a brilliant move on Tesla's part because it gives you a burst of power when you need it (E.g. to beat a corvette off the line.) :cool: As a comparison, it acts a like a burst of Nitrox in an ICE, more power, but you can't use it all the time.

[scott451]

This thread has been split... This thread (the original post) is about the effect of a hot PEM limiting performance.

Comments/Questions about the impact of a hot battery / battery cooling have been moved to this thread The-effect-of-Performance-mode-on-battery-life (http://www.teslamotorsclub.com/showthread.php/5874-The-effect-of-Performance-mode-on-battery-life)

[kgb]

Just curious... I have a question for people living in hot locales.

This is my first summer with my roadster. I live in Texas. The temperature during the day can frequently get above 100F and the thermometer in the vehicle frequently measures the outside temp (near the asphalt/concrete) as 115F or higher. As you can imagine, I need to use the wimpy A/C. As the weather was getting hotter and hotter, I noticed that my performance mode spent more and more time in the red. The other day, I was trying to give someone the Tesla grin, and the car was not "performing." So I put it into performance mode, and it would not switch out of "red." I turned off the A/C and waited, and still "red."

I mentioned to my Tesla Ranger that my vehicle was spending more time in performance limited mode rather than white performance mode, he said that I was using performance mode too much and that it would wear out my battery.

What is everyone else's experience? Do people in hot climates just have to suck it up and deal with a slower roadster in the summer?

[S-2000 Roadster]

What is everyone else's experience? Do people in hot climates just have to suck it up and deal with a slower roadster in the summer?
I wouldn't say that it's 'slower' - every Tesla Roadster is limited to 125 mph due to the single-speed gear box.

Basically, Performance Mode is more than a 10% increase in torque compared to Standard Mode, but at least Performance Mode in red is still 3% more torque than Standard Mode.

Personally, I stay away from Performance Mode, and the few times I've used it I've been able to get into the red fairly quickly. Road racing is illegal, ya know.

[scott451]

Just curious... I have a question for people living in hot locales.

This is my first summer with my roadster. I live in Texas. The temperature during the day can frequently get above 100F and the thermometer in the vehicle frequently measures the outside temp (near the asphalt/concrete) as 115F or higher. As you can imagine, I need to use the wimpy A/C. As the weather was getting hotter and hotter, I noticed that my performance mode spent more and more time in the red. The other day, I was trying to give someone the Tesla grin, and the car was not "performing." So I put it into performance mode, and it would not switch out of "red." I turned off the A/C and waited, and still "red."

If the air temp at the PEM fan intake is 115F (46C) "performance" will always be red. The A/C does not cool the PEM. If the fourth blue bar is on for the PEM in the VDS temp screen, performance will always be "red"



I mentioned to my Tesla Ranger that my vehicle was spending more time in performance limited mode rather than white performance mode, he said that I was using performance mode too much and that it would wear out my battery.Huh? When you are in "red" performance, you draw less current from the battery. So being forced into "red" by the air temp would be easier on the battery.


Do people in hot climates just have to suck it up and deal with a slower roadster [sport] in the summer?Yes.

[S-2000 Roadster]

Huh? When you are in "red" performance, you draw less current from the battery. So being forced into "red" by the air temp would be easier on the battery.
... compared to Standard Mode or full 'white' Performance Mode?

[TEG]

I wouldn't say that it's 'slower' - every Tesla Roadster is limited to 125 mph due to the single-speed gear box...
But top speed can be further limited by temp. I think I heard that flat out on the Autobahn may "govern" you down to something like 105mph on a hot day.

[S-2000 Roadster]

I'm approaching one month with the Roadster; and 2,000 miles. I'm also learning that the RED Performance Mode comes way too fast, even in the cool Pacific Northwest weather. I've had the thing turn red after only a single, full-throttle acceleration. Thankfully, it does cool down to white fairly quickly, but Performance Mode doesn't seem to be a feature that you can rely upon being there any significant amount of time.

In other words, I'm not surprised to hear that the speed can be limited. Hopefully, I'll never know.

[DrTaras]

spending more time in performance limited mode...I was using performance mode too much and that it would wear out my battery.
First, let me say that when you get advice from scott451, you are getting about the most accurate info from our non-Tesla sanctioned tech guru! Take his word to the bank!
Definitions are the lynch-pin on which answers are derived so allow me to better characterize the issue as I SUFFER frequently from it as well.

Last issue, first. I constantly use performance mode & I know that it will decrease my battery life. Using the car probably also decreases battery life (this is a metaphor so no tangent threads needed) as does hard acceleration wear down tire life (tangent thread already started elsewhere) but it is what speaks to MY soul, so keep on using "Performance" mode if it also speaks to you!

In "Performance" mode you can have the white letters which is normal, & per scott451, "If the air temp at the PEM fan intake is 115F (46C) "performance" will always be red." but that is not limiting your performance, however it is informing you that the PEM is getting quite hot and will soon get to the next threshold (scott451 will tell you what that is) where the car will LIMIT your performance and the acceleration becomes sluggish. A beep-beep is audible and I believe you will get a "power limit" come up in red on your right side of your dash board. Honestly, this is the Achilles Heel of the car and what I heard they were working on for future Teslas. How do they keep the batteries cool in extreme temperatures, either ambient or because of extreme demands on the performance. Still love the car; have had two Roadsters (tangent thread already started elsewhere) and had the same problem in each though in the 2008 they only had one PEM fan and in the 2010/11s they had 2 fans which helps the situation a bit.

kgb... welcome to the club! Membership still has its privileges!

[NigelM]

Do people in hot climates just have to suck it up and deal with a slower roadster in the summer?

Yes, but we get to drive with the top off for a huge part of the year! :biggrin:

[Doug_G]

Yes, but we get to drive with the top off for a huge part of the year! :biggrin:

Oddly enough, I don't get to use it in hot weather. Case in point: 31C (88F) here, sunny, and humid... wife takes one look in the garage and says she wants the soft top and A/C.

[NigelM]

Oddly enough, I don't get to use it in hot weather. Case in point: 31C (88F) here, sunny, and humid... wife takes one look in the garage and says she wants the soft top and A/C.

Was 96F here this afternoon, but went with the top off anyway. So long as I keep moving the air keeps me cool enough. A baseball cap is important to avoid sunburn; long waits at stop lights are miserable tho...

[Nvbob]

Um, isn't 96C about 205F?

It was about 98-102F here (Carson City, Nv) and we took a nice long drive down to Bridgeport, Ca (395 south) and back via Markleeville (Highway 89 to Highway 88 to 395). We have the Taylor Mesh Top (thank you Eric! It worked fantastically) and we were very comfortable.

[NigelM]

Um, isn't 96C about 205F?

Ooops, corrected my post. Those darned Canadian Celsius got me confused....

[Nvbob]

Nigel, why don't you PM Eric (vfx) about the mesh top? You will not regret it, it is very well worth it.

[kgb]

***
so keep on using "Performance" mode if it also speaks to you!
***
Still love the car...

I agree. Everything we do to the car decreases its life expectancy. I bought the car to use and enjoy it. If "use" results in wear and tear, so be it. I was just passing on what my Tesla Ranger told me. That said, I found that I don't need "performance" mode quite as much as I did before. I used to put the car in performance mode immediately after turning the key, now I do it "some times," or "when the mood strikes me."


Yes, but we get to drive with the top off for a huge part of the year!

I agree with Doug_G, although I find it hard to believe we live in the same climate. I have the top off September - May, summer is just too hot, and the mesh top is just too expensive for an item I can't try out first. It has those big gaps where the window doesn't make a seal, the weather is hot here, I'm just not convinced yet that this is something I need.

[vfx]

- May, summer is just too hot, and the mesh top is just too expensive for an item I can't try out first. It has those big gaps where the window doesn't make a seal, the weather is hot here, I'm just not convinced yet that this is something I need.

If you ever come to LA you can meet with someone with a Mesh Top. The airy accessory has a 100 percent satisfaction guarantee if you would like a personal test run.

[NigelM]

Having followed this thread, I have been driving a couple of days using "Performance" mode and now I'm going to take my chances and disagree with Scott (even though I acknowledge he's much better at this technical stuff than I am!):


If the air temp at the PEM fan intake is 115F (46C) "performance" will always be red. The A/C does not cool the PEM. If the fourth blue bar is on for the PEM in the VDS temp screen, performance will always be "red"

My PEM is almost always on the 4th blue bar (not surprising given our summer climate) except maybe first thing in the morning after a night in the garage. However, the "red" only comes on briefly and then changes to "white" and stays like that. I asked my Service Ranger today and he said the few seconds it is on red (on my 2.5) is just a warning that I am about to effectively reduce my range. He also said that unless I really overheat the car (continuously heavy-footed in very hot conditions) there are no performance limitations.

The Service Ranger also showed me the neat trick of giving the key an extra 1/4 turn forwards which will put the car in "Performance" mode even while driving.

That said, "kgb" the good news is that we can drive with white "Performance" at temperatures over 90F. I was driving inland at 96-97F in white "Performance" mode this morning for about 90 minutes and got back home where we live by the ocean (note the elevation!) and it's a little cooler when I took this picture as proof:

2091

[kgb]

If the air temp at the PEM fan intake is 115F (46C) "performance" will always be red. The A/C does not cool the PEM. If the fourth blue bar is on for the PEM in the VDS temp screen, performance will always be "red"

Just want to confirm that Scott451 is right again. I guess I wasn't using all my powers of observation. I could see the "red" performance on the VDS, but I failed to look for the performance limited light on the dash. I guess I assumed that it was on. Scott451 is right. The "red" performance correlates with the fourth (last) blue bar, right before the yellow. So, I guess my performance was not yet limited. So... uh, never mind... :wink:

[scott451]

Having followed this thread, I have been driving a couple of days using "Performance" mode and now I'm going to take my chances and disagree with Scott (even though I acknowledge he's much better at this technical stuff than I am!):

Do you have a sport model? (notice the word "sport" in the thread title :smile:) I believe the red performance only applies to the sport model. I don't have access to a 2010 non-sport in San Diego.



My PEM is almost always on the 4th blue bar (not surprising given our summer climate) except maybe first thing in the morning after a night in the garage. However, the "red" only comes on briefly and then changes to "white" and stays like that. I asked my Service Ranger today and he said the few seconds it is on red (on my 2.5) is just a warning that I am about to effectively reduce my range. He also said that unless I really overheat the car (continuously heavy-footed in very hot conditions) there are no performance limitations.
The 2.5 sport may have different temp limits. I'm picking up my 2.5 sport on 7/15 in Palo Alto! When I get home, I'll do an updated post with the numbers from the 2.5 [It turns out] that you don't have a sport model. [AFAIK. other than start up, you will never see red "performance" on a non-sport roadster]

[NigelM]

No Sport, just a 2011 2.5. If it's helpful, my Service Ranger also updated my firmware and said that the new one also had a better cooling cycle/management. As a further BTW, I can feel the difference in the Performance vs Standard driving modes, but it's not enough to make me want to drive in "Performance" mode on a regular basis. I'm happy to try out a few things for comparison though.

[NigelM]

OK, I admit that in earlier postings I didn't relate to the fact that this thread refers to the "Sport" model only. (Although having driven a Sport for a few days, I never felt enough difference for me to want to spend the extra money). Here's the latest experience however:

On the non-Sport 2.5 it is possible (contrary to what the Service Ranger told me) to be in Performance mode and for it to turn red and stay red. Today the outside temperature was 104F and I had 4 blue bars on the PEM and the battery and 3 blue bars on the motor. I tried out the Performance mode to see what the response was - it went red for a few seconds (as always) then turned white but immediately went back to red, and stayed red. All this was on the VDS and there was no other indicator on the dash. I decided that I didn't want to risk anything so I switched back to standard; all the time I didn't notice any change or difference in power or response.


AFAIK. other than start up, you will never see red "performance" on a non-sport roadster

Yes, you will. I have no idea what the trigger point(s) are. Previously at 4 blue bars on the PEM and 96F I was obviously below the trigger; today at 4 blue on the PEM and also 4 on the battery with 104F I was obviously above the trigger.

[smorgasbord]

I saw Performance Red on my non-Sport 2.5. I'm pretty certain it was because my battery SOC was on the low side, but I was busy thinking about other things at the time, so didn't take good notes.

[mpt]

Non-Sport or just 'Roadster'; does go red when the PEM temp increases but I don't think that we have the peak current to really push the car into 'Power Limited' on the dash (in normal road driving) but, and this is a guess that Scott could confirm, the torque is already 'limited' so no difference in torque in performance mode just the other benefits; higher battery charge level and ability to run the battery warmer.

As I think has been said before, the Sport is just* a regular Roadster with the ability to push the envelope when the PEM temp is under control.

Does a Sport in 'Standard' mode = a regular Roadster in Standard mode?

*I know, there are other differences in equipment/drivetrain, etc.

[scott451]

Non-Sport or just 'Roadster'; does go red when the PEM temp increases but I don't think that we have the peak current to really push the car into 'Power Limited' on the dash (in normal road driving) but, and this is a guess that Scott could confirm...

It's been on my todo list, but I don't have easy access to a non-sport 2.0 in San Diego. I'm in Palo Alto to pickup my new 2.5 tomorrow (7/15). I'm planning to meet up with other roadster owners on Saturday. I brought my data logger, so if I can get a ride in a 2.0 non-sport, I can post the plots pretty quickly.

[ggr]

...but I don't have easy access to a non-sport 2.0 in San Diego.


Sure you do... it's just in a different parking lot.

[S-2000 Roadster]

Does a Sport in 'Standard' mode = a regular Roadster in Standard mode?
I did a quick histogram on my Roadster 2.5, and it appears that the Sport in Standard Mode (265 ft-lbs) is the same as a Roadster in Standard Mode or RED Performance Mode. I have been able to reach 273 ft-lbs in WHITE Performance Mode, and there is also a spike at 265 ft-lbs, but the non-Sport does not seem to have a difference in torque between Standard Mode and RED Performance Mode. I'll have to do some more careful testing by driving under specific conditions so I can focus on just one part of the log file.

By the way, I discovered a huge peak in the histogram at 54.28 ft-lbs (73.596 N*m). I have no idea why that value would be so prevalent unless it's the limit in reverse. Even so, I'd be quite surprised if I've pushed reverse to the peak for that much time. It would be more obvious if my histogram were limited to a specific time range of the log.

[mpt]

I discovered a huge peak in the histogram at 54.28 ft-lbs (73.596 N*m).

Is that the torque limit at launch? The limit that exists until about 10mph is it?

[S-2000 Roadster]

I discovered a huge peak in the histogram at 54.28 ft-lbs (73.596 N*m).
This could be the maximum regenerative braking torque. I realize now that I was not checking the bit in the data which indicates the direction of power in or out of the ESS/motor. I'll run my histogram again with the full data and see what I find...

Update: Yes, the histogram peak at 54.28 ft-lbs is for regenerative braking. In one log, I have 1775 entries with that value, and 76 entries with the next lower value. There are a few spurious torque readings: 59, 63, 72, and 106 ft-lbs; but those only occur once each, so they don't seem significant.

There is no spike in the histogram for forward torque in that area - just normal readings as would be expected without special meaning for that torque level.

I will try to figure out whether there is any obvious torque limit at launch (that can be detected in the logs), and also continue looking for evidence that the non-Sport Roadster has any difference in torque between Standard Mode and RED Performance Mode.