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It's alive! [All spoiler, no speculation]
- Thread starter omgwtfbyobbq
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- Model 3
Either increasing volts or amps is problematic. Going to 800v is more elegant due to wire size. If the German's are going to really build 800v charging system, I think Tesla's would have that goal too.
Either approach is challenging due to the added Supercharger cost.
For whatever it's worth, my Volt "idled" at around 400W with all the computers and drive inverter live but the HVAC off.
I think the AP sensor units are each single digit watts, but the NVidia computer is rated for up to 300 or so maximum? Not sure how high it normally runs, though.
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With all the system level issues (switching losses, clearance/ creepage requirements, contactor clearances), just doubling the number of charging wires would be simpler. Since automated chargers will be needed to automated cars, the extra cable mass is a minor factor.
It could be, but that should be included the the energy consumption figures for the 2 steady state 55mph tests, and it should also be proportional to speed and distance travelled. The point of including baseline is to make the very low speed range estimates a little more accurate. The Leaf's most efficient speed is ~12mph because of this instead of someplace in the 0-5mph range, and I imagine the 3 is around there too. Kman measured baseline power at 274W for the S, so I'm thinking 200W for the 3 is realistic, but it could be lower.
Energy Consumption Of Various Tesla Heating Features
I suppose enlarging the S/X charge port area could be an indicator of a future double connection. But I doubt Tesla really does robotic Supercharger connections. Not enough customer benefit. High end car buyers choose to pump their own gas.
I think a "no touch" home charging system would be widely attractive, however.
Without robotic chargers, are you envisioning a person to handle charging at each SC location once Tesla Network rolls out? I suppose TN could only use the extra capacity you have since it knows what your drive home would take.
You just ignored the fact that they enlarged it just to have the built-in connector for cina, and i would expect that the same could and should be done for europe/usa when there is a clear winner
True. Is 20% voltage sag what is normally seen? So 320kW, that is still 430+HP from the battery which is respectable.
Wasn't there rumors about the inverter being capable of ~350kW?
Also, anyone know what the kW rating for the motors of the S and X are in the EPA docs? This one lists the motor at 192 kW @ 5000rpm (257HP), but sometimes these motor ratings are for continuous load vs peak output.
There is one more option (but yes, I do know - not really an SuC alternative) - inductive charging. And this is clearly in the spirit of N. Tesla
But regarding the robotic chargers, most people seams to think about that "snake" that Tesla showed some time ago. But there is other options...
There is the alternative that Tesla patented with a plug with cooling coming in from the floor/ground. And if not that, look at some of the proposed charging for buses and trucks. Some of them may be possible to modify to work on autonomous cars.
We don't know much about the 2170 cells, chemistry, and how they perform under load versus the 18650's in the Model S/X. 20% may be a bit of an over-estimation.
insaneoctane
Well-Known Member
Let's try this again. Now that I've had some time to review the data on my desktop computer
I used the Highway Fuel Economy Driving Schedule (HFEDS) and found a table that broke down the cycle down to the second. I used a combination of *assumptions* to calculate the energy gained/consumed at each second. I used this data to back-out the "fixed" load of the car, which turned out to be approximately 600 Watts. This seemed reasonable to me. Here's all the assumptions I made to get it (for you guys to pick apart):
The part of the graph that has me wondering is the long range at say 40 or 50 or 60. Now, this assumes complete steady state, which is a HUGE idealization. Anyway, it's interesting nonetheless. Probably overkill and more data/info than most wanted, but these are the type of analysis that keeps me entertained while I wait for my M3!
As a side note, it looks like the hypermiling challenge is at 22 MPH for 674 miles with the 18" wheels.
I used the Highway Fuel Economy Driving Schedule (HFEDS) and found a table that broke down the cycle down to the second. I used a combination of *assumptions* to calculate the energy gained/consumed at each second. I used this data to back-out the "fixed" load of the car, which turned out to be approximately 600 Watts. This seemed reasonable to me. Here's all the assumptions I made to get it (for you guys to pick apart):
- 65% efficiency for regen braking energy recovery
- 85% efficiency for conversion of energy to acceleration (battery, inverter, wires, motor, etc)
- Total Energy used was (Fixed) + (ABC coast down) + (acceleration)
The part of the graph that has me wondering is the long range at say 40 or 50 or 60. Now, this assumes complete steady state, which is a HUGE idealization. Anyway, it's interesting nonetheless. Probably overkill and more data/info than most wanted, but these are the type of analysis that keeps me entertained while I wait for my M3!
As a side note, it looks like the hypermiling challenge is at 22 MPH for 674 miles with the 18" wheels.
It looks better to me. I would still change a couple things. The results from the application show with a reasonable degree of certainty that the 3 has ~360 miles of range at a steady 55mph, which is about a hundred miles less than the graph suggests. I think the range of the Sport and Aero wheels will also diverge more at higher speeds, given that there's already a ~12% difference at 50mph.
insaneoctane
Well-Known Member
Which results are you talking about?
For the 18" wheels, if I look at 55mph, fixed losses of 600W equates to 10.9 Wh/mi and coast down calculated losses are 164.6 Wh/mi. Which part of that doesn't sound right?
If I were truly ambitious, I would try my model against the EPA city cycle and see if it matches Tesla's 495 mile result
insaneoctane
Well-Known Member
The application in the first post has the actual five cycle test result ranges/energy use near the end. In terms of miles driven, most of the five-cycle test is done at a constant 55mph, so they pretty much handed the energy use per mile at 55mph to us over about 320 (I think) miles. The maximum range at 55mph can be calculated by dividing the total energy not used on the 55mph segments by the the energy consumption average from the existing 55mph segments, and adding it to the ~320 miles(?) of 55mph driving, which I believe is ~360 miles.Which results are you talking about?
For the 18" wheels, if I look at 55mph, fixed losses of 600W equates to 10.9 Wh/mi and coast down calculated losses are 164.6 Wh/mi. Which part of that doesn't sound right?
If I were truly ambitious, I would try my model against the EPA city cycle and see if it matches Tesla's 495 mile result
Edit - Or you can just scale your existing road load graph by ~76+% and likely end up with the same result. Higher power should be maybe 5% more efficient, most due to relatively (it's still great, 85-90% instead of ~95%) low motor efficiency at low torque.
I believe we also have the Crr for the 3 with Aero wheels, which should be coefficient A over the test weight, and we also have the road load at 50mph and test weight. From that information, you can come up with an accurate estimate for CdA by adjusting it until your road load estimate matches the 9.95hp from the application and you can generate the RLHP curve for the S with Aero wheels. Scaling that to the actual range at 55mph from the last step, since the graph is just road load and not total energy consumption (the bearings, trans, motor, inverter, and pack/bms all use a little power getting it to the wheels, which I estimated to be ~76%) should get a reasonably accurate graph of range versus speed.
You can do the same thing for the 3 with Sport wheels, but you would need to adjust the `~360 miles at 55mph down by >12% (13-14%?), recalculate Crr (larger tires are a smidge higher), and then use it's I think slightly higher curb weight and higher RLHP at 50mph to estimate it's CdA. From there, range can be scaled just like it was with the Aero wheels. It won't be quite as accurate because we don't have the results of the 55mph test sections over 300+ miles, but it should be good enough for jazz.
T34ME
Active Member
Thanks @insaneoctane , these graphs look much more believable. I will let others quibble about the details which are beyond my expertise. I think we are getting much closer to real world expectations with your current graphs above.
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