TESLA high performance tuning discusion
- Thread starter Doctorbass
- Start date
Hillhater
100 TW
^^..doesn't Justin have the solution to that already trusted and available ?
liveforphysics
100 TW
Hillhater said:
The Tesla inrunner rotor has a smooth outside and no permanent magnets. Not saying it can't be done, but I wouldn't jump to assuming it's a viable option until tested.
Again, if someone wants to drop off a P90D for me to hack on, it would be my pleasure to find out.
ATB,
-Luke
speedmd
10 MW
Where does the line form for this task? I'll be second. :lol:
liveforphysics
100 TW
speedmd said:
If you think you can do it, be my guest. I think Im at least 98% likely to achieve successfully hacking one to deliver all the power its capable of, and/or add adquate battery to the vehicle to sustain the motors in saturation for the duration of the quarter mile. Im also confident I could get another rear motor drive assembly into the front, even if it requires a lot of customization.
The fee is a p90d + parts (used is OK, but no p85d's, as I don't think the cell is as well suited for finding the edge of the envelope). My labor is bought with the p90d. Which is also used as the development prototype car to hack on and figure out how to do it. I don't care how many times my own development car is broken provided parts for further development and ending up with the same set of functional parts that goes into your own car after we find the real limits.
I am comfortable in my ability to completely find the limits of the vehicle and what breaks first, second, third, etc, and find a solution to each of those obsticles if adquate budget is provided to get some custom parts machined or whatever it takes (essentially throw money at it as an overkill lazymans fix for each thing that breaks). I learned that process well in over a decade of formerly choosing to convert the majority of my paychecks into twisted up paperweights that resemble portions of engine bearing/transmission/clutch/axle/gearset/block/valves/rods/pistons etc.
The Tesla has only stator/rotor/bearings/gearsets/axles to potentially need beefing up, and perhaps most it can remain OEM, wont know until we are finding the limits of satuation with a sticky tire.
speedmd
10 MW
Honestly, you are the guy that Elon should be building one of many skunk works around. No brainer IMO. What they would benefit from a fresh look and some free thinking is priceless.
Doctorbass
100 GW
Luke That's exactly what discussion i expected to have in that thread :wink:!
Doc
Doc
macribs
10 MW
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jonescg said:
I think that is what Saleen has done with their GTX. Better cooling of controller and batteries. How they did it I don't know for sure, but I am guessing the rework of the front bumper is to let more air flow through. So it seems that a new bigger and fatter radiator would be the natural way to go. Perhaps even increased the diameter of the cooling pipes etc to allow for higher flow of liquid. As I said I don't know how they did it, just guess working here.
Main thing is that it is possible to turn model s into track friendly car, Saleen already did with the GTX.
Notice I said track friendly, and not track car. It would take some serious liposculpture, low carbo diet and a doze of magic to remove half a ton or so
kiwiev
100 kW
The AMR dual stack motors are getting good numbers down here. Brett from Elmofo with his radical 8 which is set up for circuit racing 50km range. Took it to Sydney race way and posted 9 second 1/4 miles and 210kph.
Biggest problem he was wheel spinning the first 1/8 of a mile. I wonder if these motors would be a better option.
Cheers Kiwi
Biggest problem he was wheel spinning the first 1/8 of a mile. I wonder if these motors would be a better option.
Cheers Kiwi
MrDude_1
100 kW
Punx0r said:
I'm not aware of any automotive manufacturer rating their vehicles in HP in reality. It is set by lawyers. For example, in 2004 when the SAE measurement standard for calculating it changed (SAEJ1349), some manufacturers had to re-rate everything. All the high hp 4cyl cars suddenly made less power. Options started to matter. Meanwhile GM could INCREASE what the claimed rated power was...
there are a couple neat articles about it if you google it, but i have this one bookmarked:
http://www.caranddriver.com/columns/larry-webster-horsepower-confusion-and-resolution-column
okashira
10 kW
eTrike said:Thanks for crunching the numbers, I made a couple notes but mainly question the battery loss number?
okashira said:Tesla has published their actual hp numbers. I was only about 8% off or less in my estimates from 6 months ago.
Good call, apparently an open letter prompted a response from the CTO on why the 691hp wasn't seen on a dyno and that number has now been corrected with an * for "Battery limited maximum motor shaft power". While I understand the confusion, I don't know if any manufacturer accurately reports WHP. Yay for truth in advertising though, Tesla can revolutionize that field too. :lol:
Their torque numbers are quite a bit lower than some have reportedly dyno'd, though I'm more inclined to believe the lower number.
The numbers are even lower then I estimated.
532 hp (Ludicrous)
463 hp (Insane)
We know L is 1500A or 20.2A per cell. Do we know it does the full 1500A?
NCR18650GA would sag to about 3.34V per cell under a quick load at near full charge when loaded to 20A. Seems about right but I haven't found a test to confirm. Calc estimates 3.32, close enough?
If hot, it might sag to 3.45V. Curious about the cold sag right now, my poor batts are freezing with this recent weather. Naturally Tesla has that managed.
That's 67.47 W per cell or 479.3kW cell power in the car.
532hp is 396.7 kW.
So at full load the rest of the system efficiency is 396.7/479.3 = 82.8% This includes losses from: all wiring, fuse wires, connections, inverter, motor.
That is really good considering how small of an induction motor it is for the power. Seems about right. Any info on peak efficiency of inverter?
Note that the battery cell losses amount to an additional 115kW of losses. (4.15V - 3.34V) * 20.2A * 7104 This is where you lost me. That number seems awfully large at a glance. I think your first "*" should be a "/". R=V/I, eh? With that I get about 6kW of heat. Your efficiency math makes sense for the whole system so I think batts would be included in that.
It brings up an interesting point about thermal management though. Apple's beefiest workhorse received the iPhone treatment a couple years ago and became a much smaller cylinder, shying away from literally every preceding Mac Pro design. In doing so they removed a number of desirable features that power users are accustomed to in favor of volumetric efficiency. Despite a glaring thermal design flaw they patted themselves on the back and made a mint because Apple.(sic) Once the design hit the real world, the flaw left users with an insanely expensive computer that would derate itself in the interest of self-preservation. I worked for them at the time and saw several other practices that were shady at best. There is a reason they have a fraction of the market and a majority of the profits, and it isn't based in ethics. /rantoff
My point is that Tesla could benefit from isolating their heatsinking, because the vast majority of power dissipation needs comes from motor and inverter.
That brings total efficiency at peak load to 396.7/(479.3+115) = 66.8%
disclaimer: I am quite sleep deprived atm, so as always I welcome any corrections. Thanks again for the info!
No, my battery calc is right. I assumed the rest voltage of the cell is 4.15V, and you load it such that the terminal voltage is 3.35v. the power lost is (4.15-3.35)*A in one cell.
Thus the only way to get 100% effieincy is to use a quasistatic load
The rear inverter uses 20x IKW75N60T in parallel per phase. If we assume 1200/20=60 amps you might get a Vce of 1.5V, so >99.5% eff. The conduction losses of the connections and switching losses are probably more then that.
Probably about 99% for the inverter overall at max load.
The motor is most of the losses. And the battery is by far the most at peak load.
MrDude_1
100 kW
eTrike said:
Their inverter is a work of art. I dont know who designed it, but I would buy everyone on that team a beer. lol.
nieles
10 kW
okashira said:
the only fair way to calculate battery losses is with the formula I^2*Ri where Ri is the internal battery resistance
okashira
10 kW
nieles said:
That's a terrible way to do it if you want an accurate result, as a battery is not a resistor.
The resistance is highly variable and is a function of time, recent loading conditions, temperature, SoC, and age.
We are getting there....Hillhater said:
There is a lot of talk on here about how a powerful brushless motor is needed.
Here is the motor I just installed in my drag car. We are finishing size reduction on the controller.
8phase 4 pole permanent magnet motor, should be good to 2000HP.
Wheazel
10 kW
Arlo1 said:
Talk about current top tesla S drivetrain in a lighter roadster.
https://www.youtube.com/watch?v=iVGsWvRa1XA
MrDude_1
100 kW
Wheazel said:
the guy doing this clearly has never been into drag racing.
It reminds me of this: http://jalopnik.com/did-neil-degrasse-tyson-screw-up-a-tweet-about-basic-ph-1582030197
MrDude_1
100 kW
same with thinking you need 4wd. :lol:Arlo1 said:
I do find it funny when people are talking about modding cars for "the quickest" without ever looking up what a couple rednecks can do with a 50 year old car. never-mind what actual pros and engineers can do... :lol:
