World's Greatest Tesla Model S P85D Review Series Videos

[Kevin Michaluk]

Very good video! Thanks.

Just wondering why you'd want to set the regenerative braking to low, though. It seems to me the only thing that would accomplish is putting less energy back into the battery at the end of every run, when you need to slow down. Since I imagine you had no way to charge at the track, and since you were clearly running several times, I'd think every little bit of juice would help, so that you'd want the energy gained from standard regenerative braking after the runs end.

Good question/thought. So... because the racing started as a single knockout event, wasn't thinking about saving energy for multiple races. Didn't know if regen breaking could affect the acceleration part (since you're on the pedal and not touching the brakes), but *just* in case decided to turn it off. Figured it couldn't make the car slower... and maybe, just maybe having it off helped with a fraction of a millisecond of a speed up. That said, I think you're right.. if you're doing multiple runs makes sense to get the regen bonus back into the battery.

 

[alexeiw123]

Turning regen off helps on track days, (so I'm told) by giving the pack a chance to cool while you're not accelerating. As regen is still current going through your pack. You can make a small difference to the time until the yellow dotted line shows up. Obviously, much more reliance on the mechanical brakes.

No help in straight line drags though.

 

[beeeerock]

I've always been under the impression that regen stops as you slow down below ... dunno... 3 or 4 km/h? Feels like that to me anyway, and thought I saw it mentioned in the manual somewhere too.

 

[alexeiw123]

I've always been under the impression that regen stops as you slow down below ... dunno... 3 or 4 km/h? Feels like that to me anyway, and thought I saw it mentioned in the manual somewhere too.

The slower you go, the less effective regen can be. It's a characteristic of AC motor/generators. Slow rotation of the rotor doesn't generate enough flux for a rotating magnetic field to form.

 

[Mayhemm]

So where is the drag strip in Winnipeg?

I'll have to work on Sun Country Highway and get a charging station out there!

 

[Kevin Michaluk]

Turning regen off helps on track days, (so I'm told) by giving the pack a chance to cool while you're not accelerating. As regen is still current going through your pack. You can make a small difference to the time until the yellow dotted line shows up. Obviously, much more reliance on the mechanical brakes.

No help in straight line drags though.

Makes sense! Thanks for that tid bit.

- - - Updated - - -

Went to the drag strip in Gimli (which funny enough, is where I grew up.... literally right next to it. Think my family's home is the closest one to the airport/dragstrip there).

 

[gavine]

Regen has nothing to do with the brakes-themselves. It's called regenerative "braking" because it slows down the car, but it doesn't use the brakes. It uses the motor to slow the car so setting it on low doesn't affect acceleration at all.

 

[beeeerock]

The slower you go, the less effective regen can be. It's a characteristic of AC motor/generators. Slow rotation of the rotor doesn't generate enough flux for a rotating magnetic field to form.

I understand the principles, but recall reading or hearing from my agent that there was a point where the regen just stops. Given that the gearbox is there to reduce the motor drive speed to what makes sense at the wheels, I find it hard to believe that the isn't enough rotation to generate *something*. However, at almost no speed, the kinetic energy available is almost insignificant, so regen could likely pull you down to a quick stop when you're getting close to zero speed. That wouldn't be pleasant and doesn't imitate what we're used to in any car.

I have regen set to the normal higher mode and believe I can feel it relax the drag as I hit around 5 km/h, like it was just turned off, not tapering down due to less kinetic energy being available.

I can't find reference to this in the manual now that I've looked again, so perhaps it was my delivery agent that mentioned it. He could have been wrong, but it fits with my driving experience.

 

[Andyw2100]

I understand the principles, but recall reading or hearing from my agent that there was a point where the regen just stops. Given that the gearbox is there to reduce the motor drive speed to what makes sense at the wheels, I find it hard to believe that the isn't enough rotation to generate *something*. However, at almost no speed, the kinetic energy available is almost insignificant, so regen could likely pull you down to a quick stop when you're getting close to zero speed. That wouldn't be pleasant and doesn't imitate what we're used to in any car.

I have regen set to the normal higher mode and believe I can feel it relax the drag as I hit around 5 km/h, like it was just turned off, not tapering down due to less kinetic energy being available.

I can't find reference to this in the manual now that I've looked again, so perhaps it was my delivery agent that mentioned it. He could have been wrong, but it fits with my driving experience.

I thought I remembered reading, in the manual, that regenerative braking did not work below 5 MPH. I looked again, and can't seem to find that now. It could have been edited out of the current version of the manual, after having existed in a previous version.

 

[Doug_G]

I would recommend turning Regen to low for the race track, to minimize drive train heating. Drive train heating is what causes you to get power limits.

Also on the track, regen tends to interfere with weight transfer for the corners, so that's another good reason for setting it to low.

For drag racing, I wouldn't bother. Leave it on high, and use it to recoup a little energy after each run.

 

[physicsfita]

I understand the principles, but recall reading or hearing from my agent that there was a point where the regen just stops. Given that the gearbox is there to reduce the motor drive speed to what makes sense at the wheels, I find it hard to believe that the isn't enough rotation to generate *something*. However, at almost no speed, the kinetic energy available is almost insignificant, so regen could likely pull you down to a quick stop when you're getting close to zero speed. That wouldn't be pleasant and doesn't imitate what we're used to in any car.

I have regen set to the normal higher mode and believe I can feel it relax the drag as I hit around 5 km/h, like it was just turned off, not tapering down due to less kinetic energy being available.

I can't find reference to this in the manual now that I've looked again, so perhaps it was my delivery agent that mentioned it. He could have been wrong, but it fits with my driving experience.

The issue with regenerative braking is that the braking force decreases with the velocity of the car. So, although there's less kinetic energy left, the motor (acting as generator) can't remove it as quickly as it could when the car was going faster. If you were to try to regeneratively brake all the way to a stop, it would take you literally forever to achieve that. (Of course, rolling friction would eventually bring you to a halt.) For practical systems, you have to switch over to some other form of braking to get the last little bit done. For instance, a Prius transitions to friction-pad brakes at about 7 MPH, where the friction brakes are now more effective. My understanding for the Tesla is that it has two modes: you can activate the friction brakes with the brake pedal, or the car can start to switch the motor back to being a motor (from being a generator), but applying a reverse torque to slow the car down.

 

[tdelta1000]

Looking forward to your review of the P85D Model S.

 

[JRP3]

If you were to try to regeneratively brake all the way to a stop, it would take you literally forever to achieve that.

I don't know how Tesla has it set but in my home built EV conversion I can regen all the way to a complete stop. It does take a bit of planning ahead but it certainly does not take forever.

 

[physicsfita]

I don't know how Tesla has it set but in my home built EV conversion I can regen all the way to a complete stop. It does take a bit of planning ahead but it certainly does not take forever.

I was focusing solely on regen. A real-world system also has rolling friction to take care of the last little bit. Also, as I said, the controllers can be set to have the motor provide an adverse torque for the last part of the braking profile; Tesla, in their blog posts, characterizes this as part of regenerative braking. This is not strictly correct from a physics viewpoint as (admittedly, a relatively small amount of) energy is being drawn from (not sent to) the battery for that purpose.

 

[Kevin Michaluk]

Newest video is up! Passed 500 miles on the odometer so figured I would check in with my impressions so far. Just like the radio, I turned it up to 11 for this with 11 Awesome features!

I hope you enjoy it!

 

[Andyw2100]

Newest video is up! Passed 500 miles on the odometer so figured I would check in with my impressions so far. Just like the radio, I turned it up to 11 for this with 11 Awesome features!

Another excellent video! I do again, have a couple of points to make, however.

The information you provide about pressing and holding the roof button on the keyfob to open and close the windows is just wrong. That hasn't worked for quite some time -- a year or more, I believe.

Also you refer to the app on your Apple watch as the "Model S App." Considering all the work being put into it by a TMC member, why not refer to it by its correct name, "Remote S?"

If you do wind up editing and re-releasing the video because of the window issue, it would be great if you also voiced over or re-recorded the part about Allen's app.

Just my 95 cents!

 

[Kevin Michaluk]

Another excellent video! I do again, have a couple of points to make, however.

The information you provide about pressing and holding the roof button on the keyfob to open and close the windows is just wrong. That hasn't worked for quite some time -- a year or more, I believe.

Also you refer to the app on your Apple watch as the "Model S App." Considering all the work being put into it by a TMC member, why not refer to it by its correct name, "Remote S?"

If you do wind up editing and re-releasing the video because of the window issue, it would be great if you also voiced over or re-recorded the part about Allen's app.

Just my 95 cents!

Thx for the feedback! Good catch on the keychain button - thought we had that removed from the edits (figured out it didn't work!) but somehow it accidentally made it into the final cut. Not really a big issue though (not one to re-release video for). Re: Watch App... I said "being able to use the Model S App and my Apple Watch to check in on the car..." I was speaking to the phone app there and Apple Watch (not the Apple Watch specifically) so wasn't attempting to say Remote S and got the name wrong (I can see the confusion though because we edited in the photo of the Apple Watch w/ Remote S app there instead of showing off the phone app. That said, I'll add a link in the description of the video to get to the Remote S app.

Thanks again - maybe I should DM you the unlisted youtube links to future videos before they go live. Can catch things like his in advance of hitting publish!

 

[alexeiw123]

Gave that girl a nice fright at 1:15!

 

[Andyw2100]

Thx for the feedback! Good catch on the keychain button - thought we had that removed from the edits (figured out it didn't work!) but somehow it accidentally made it into the final cut. Not really a big issue though (not one to re-release video for). Re: Watch App... I said "being able to use the Model S App and my Apple Watch to check in on the car..." I was speaking to the phone app there and Apple Watch (not the Apple Watch specifically) so wasn't attempting to say Remote S and got the name wrong (I can see the confusion though because we edited in the photo of the Apple Watch w/ Remote S app there instead of showing off the phone app. That said, I'll add a link in the description of the video to get to the Remote S app.

Thanks again - maybe I should DM you the unlisted youtube links to future videos before they go live. Can catch things like his in advance of hitting publish!

I see what you mean about the app, the watch, and Remote S. I was just trying to look out for one of our own!

If you're serious, I'd be happy to take a look at your videos before you release them, to see if I catch any little errors. If you were kidding, that's fine too, of course!

 

[Kevin Michaluk]

I see what you mean about the app, the watch, and Remote S. I was just trying to look out for one of our own!

If you're serious, I'd be happy to take a look at your videos before you release them, to see if I catch any little errors. If you were kidding, that's fine too, of course!

Totally serious. Usually upload one pre-final edit before I'm putting them live, so can send you those links (it's unlisted so you can view it... just don't share it yet). Going to be a while before I'm an expert on all things Tesla, so extra eyes always good!