Power Limited at High Speed?

[mknox]

First off, this is a dumb thing I did and don't recommend it.

The other night on my way home from work, some guy in a heavily tricked out (and very noisy) 3-series obviously spotted me on the freeway and started pacing me and going back and forth. His windows were so dark, I couldn't see the driver at all.

Anyway, he eventually pulls in front of me and gradually starts slowing down. As I move over to pass I hear his exhaust note and he takes off, so I jab the accelerator too. Obviously he wanted a little race. He actually overtook me, but when I hit about 110-120 MPH I noticed the dashed "power limit" line appear on the power meter. It went away as soon as I backed off the accelerator.

I've read in some of the threads covering racetracks that the Model S starts limiting power after a couple of laps, but this whole exercise of mine was no more that 10 or 20 seconds. It was a quick burst of speed, then back down to normal freeway speeds.

Is that normal? Surely I couldn't have overheated anything in that brief time.

 

[Rodolfo Paiz]

I don't believe you overheated anything or forced anything. The Model S appears to be software limited to a maximum speed of 125-130 mph, so getting your power limited makes perfect sense.

 

[mnx]

I've seen it power limit under full accelerator while nearing 170km/h... Yours is a standard 85 correct?

What was your SOC?

First off, this is a dumb thing I did and don't recommend it.

The other night on my way home from work, some guy in a heavily tricked out (and very noisy) 3-series obviously spotted me on the freeway and started pacing me and going back and forth. His windows were so dark, I couldn't see the driver at all.

Anyway, he eventually pulls in front of me and gradually starts slowing down. As I move over to pass I hear his exhaust note and he takes off, so I jab the accelerator too. Obviously he wanted a little race. He actually overtook me, but when I hit about 110-120 MPH I noticed the dashed "power limit" line appear on the power meter. It went away as soon as I backed off the accelerator.

I've read in some of the threads covering racetracks that the Model S starts limiting power after a couple of laps, but this whole exercise of mine was no more that 10 or 20 seconds. It was a quick burst of speed, then back down to normal freeway speeds.

Is that normal? Surely I couldn't have overheated anything in that brief time.

 

[NigelM]

Top speed is software limit to 130mph, but the power limiter will kick in if your SOC is getting low or if any of the drive train components get too hot. There's an interesting short video showing 0-133mph here: tesla-model-s-top-speed-run-video

 

[mknox]

I've seen it power limit under full accelerator while nearing 170km/h... Yours is a standard 85 correct? What was your SOC?

Yes, a Standard 85. My SOC was probably near 40% at that point.

- - - Updated - - -

Top speed is software limit to 130mph, but the power limiter will kick in if your SOC is getting low or if any of the drive train components get too hot. There's an interesting short video showing 0-133mph here: tesla-model-s-top-speed-run-video

Thanks. It looks like the power was actually exceeding the dashed limit line for a while, but the video was a bit shaky. That's pretty much what I saw.

 

[brianman]

Top speed is software limit to 130mph

It's 130 on the P85. It's 125 on the non-Perf.
(Hence, max's question to mknox: "Yours is a standard 85 correct?")

As you noted we have video showing 133 in a Perf. I believe there was a report and/or video of 128 in at least one non-perf. I don't recall where it was posted though.

- - - Updated - - -

Obviously he wanted a little race. He actually overtook me, but when I hit about 110-120 MPH I noticed the dashed "power limit" line appear on the power meter. It went away as soon as I backed off the accelerator.

When it comes to racing with the Model S and speeds above 120, here is some advice:

 

[islandbayy]

I got the dotted lines when I maxed a P85 on a 0-130 test. I was at about 100 when it the limiter came on. I had done multiple tests, State of charge, had about 150 ish miles left. I believe, since it did not come on on the first tests, it was the battery pack heating up.

 

[Zextraterrestrial]

about 10 sec of hard acceleration will limit it a tad

 

[Doug_G]

Anyway, he eventually pulls in front of me and gradually starts slowing down. As I move over to pass I hear his exhaust note and he takes off, so I jab the accelerator too. Obviously he wanted a little race. He actually overtook me, but when I hit about 110-120 MPH I noticed the dashed "power limit" line appear on the power meter. It went away as soon as I backed off the accelerator.

Yes, as you approach the vehicle's maximum speed, the car starts pulling back on the power. That happens even if the drive train is stone cold.

Don't expect to win any races above 100 mph; you can see in this video that I start to lose ground towards the end of a 1/4 mile run:

The first 1/8 mile nothing can catch you!

 

[sublimaze1]

From running the battery past O rated miles, I will say that the dotted line results from the calculation of what the batter can/will give you. The dotted line will creep downwards closer and closer to 20, which makes you think "brick" -
- but more to your point, I surmise that whatever combination of variables existed (temp, SOC, coolant flow, etc.), the computer decided that the dotted line was all it was able to safely dump into the motor, and that's that.

A friend of a buddy's dog groomer's wife's bridesmaid's brother told me that the dotted line does not show up at 124 miles/hr when it is about 70 degrees outside in mid April on a 75% SOC on the access road to the North Dallas Tollway.

 

[brianman]

A friend of a buddy's dog groomer's wife's bridesmaid's brother

I can't resist unravelling that one (and props for the movie reference)...

Did your sister like her bridesmaid's dress, or did the dog groomer's wife pick out ugly ones?

 

[bonnie]

I can't resist unravelling that one (and props for the movie reference)...

Did your sister like her bridesmaid's dress, or did the dog groomer's wife pick out ugly ones?

squirrel!

 

[brianman]

squirrel!

The squirrel version was a Signature vehicle. You gotta look on ebay.

: )

 

[mknox]

Don't expect to win any races above 100 mph; you can see in this video that I start to lose ground towards the end of a 1/4 mile run:

Well, the guy did get a bit of a jump on me. Seriously... I've had people slow down in front of me a lot I think because they're checking out the car in the rear-view mirror. When I pull around to pass they're usually just checking out the car as I go around. This time when I started to move in to the passing lane he gunned it and since I already had my foot into it a bit to pass, and I realized what was going on, I did too. It is amazing how quickly the car jumps into triple digit (MPH) speeds and fairly quickly I realized I was on a public road and backed down. As I say, this might have been a 20 second exercise.