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Fred Thompson
Member
If Tesla installs larger batteries in their vehicles and allows software updates to increase mileage range at 5 kWh increments or larger and advertises the capability, more people would purchase their vehicles.
Tesla’s ‘upgradable’ battery may change the way we buy cars
Tesla’s ‘upgradable’ battery may change the way we buy cars
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Red Sage
The Cybernetic Samurai
It seems the EPA rather agrees with you.
Compare Side-by-Side
RAV4 EV at 440 Wh per mile...
Model S 60 at 350 Wh per mile.
My argument is that this is caused by the low output of the motor in the RAV4 EV, limited to only 154 HP per Toyota. I believe the motor is operating below its maximum efficiency.
Red Sage
The Cybernetic Samurai
I believe that if Tesla Motors has a starting internal cost below $110 per kWh for battery packs from the Gigafactory, 70 kWh is achievable at the $35,000 base price and would allow for up to an initial 12% profit margin. 60 kWh would work at $128 per kWh or less.
I responded to another, similar point elsewhere with the following:
When the Model S arrived, its battery pack held about 40% more energy than the capacity of the Tesla Roadster battery pack, using fewer 18650 battery cells. The technology had advanced that much over the course of four or five years. I expect that a similar process will have happened since 2012 by the release of Model ☰.
If the difference between 2012 and 2017 is only a 30% improvement by volume... Then an 85 kWh battery pack could occupy only 70% the space as before. And a 100 kWh battery pack could be installed in only 82% of the volume for a 2012 85 kWh battery pack. That's pretty close to the 20% volume difference that Tesla Motors has strived for with Model ☰ as compared to Model S. And a 90 kWh battery pack would occupy only 74% as much volume as an 85 kWh battery pack from 2012.
So, no... I'm not being overzealous here at all. There is plenty of space, even in a smaller Generation III vehicle, to include as much battery pack capacity as is currently available for Model S and Model X. This is why I focus on capacity instead of the phrase 'bigger battery pack' as others tend to use. The real question is whether my hopes for improved energy density come through, and if Elon and JB choose to maximize the potential for range through smaller capacities and greater system efficiency and/or filling the battery pack with as many battery cells as it could possibly hold.
And this was a reply to another protest over my projections of what the Model ☰ might someday offer:
Some have said, I'm not sure if this is true or not, that the 60 kWh battery pack had 'dummy' cells in some modules to act as 'ballast'. I've always found that theory strange, since the 60 kWh version of the Model S weighed quite a bit less than the Model S 85. My guess is that they were simply empty modules installed alongside fully populated ones in the casing. I think the physical case for the Generation II battery pack is the same size and shape regardless of the number of active modules within it.
When the 90 kWh battery pack first arrived, I remember someone stated that only a single module within the 85 kWh battery pack was upgraded to reach that capacity. I have no idea where I came across that notation. I've looked, but it seems I never made a bookmark to the discussion, and I cannot find it via web search.
Since then, every discussion I have seen has said that Tesla Motors increased the capacity from 85 kWh to 90 kWh by using a new formulation of battery cells through the entire battery pack. At first, that seemed like it might be true... But then I thought, the 85 kWh battery pack has 16 modules in it. If 5 kWh were added to the battery pack by changing all the battery cells, that means that Tesla Motors decided it was worth it to release a new battery cell design that increased capacity by 0.3125 kWh, or 312.5 Wh per module. That really isn't very much...
Since then, every discussion I have seen has said that Tesla Motors increased the capacity from 85 kWh to 90 kWh by using a new formulation of battery cells through the entire battery pack. At first, that seemed like it might be true... But then I thought, the 85 kWh battery pack has 16 modules in it. If 5 kWh were added to the battery pack by changing all the battery cells, that means that Tesla Motors decided it was worth it to release a new battery cell design that increased capacity by 0.3125 kWh, or 312.5 Wh per module. That really isn't very much...
My thought is that isn't the case at all. I expect that one or two modules in the 90 kWh battery pack use new battery cells, but all the rest use the original formulation from 2012. If it was two modules, then instead of having a 5.3125 kWh capacity per module, they were increased to 7.8125 kWh each. If it was one module, then it was increased to 10.3125 kWh.
Here is why that is important:
Here is why that is important:
- Using two modules at a time to increase capacity by 5 kWh increments, Tesla Motors can gradually increase maximum capacity as they see fit... Going from 90 kWh to 100 kWh by adding four more of the new type of modules... Then increasing to 120 kWh by adding eight more modules to max out the Model S and Model X by filling the entire battery pack with the new formulation.
- Using one module at a time to increase capacity by 5 kWh increments, Tesla Motors can gradually increase maximum capacity to as much as 165 kWh by filling all 16 modules with the new type of battery cell for use in Model S and Model X.
- And for the sake of argument, if it is four modules to add 5 kWh, the maximum would be 105 kWh.
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Red Sage
The Cybernetic Samurai
Red Sage
The Cybernetic Samurai
I believe it would be...
AWESOME
...if the only battery capacity offered were 100 kWh for the first 18-24 months. Yes, at the $35,000 base price. Then release a 70 kWh version at $25,000 or so.
But, that would probably be crazy. Aren't you glad I don't run Tesla Motors? Yeah.
Red Sage
The Cybernetic Samurai
It would have to average below 202 Wh per mile over the entire 5-Cycle test to get just 300 miles. If you use the magic ~194 Wh per mile number, you may see 318 to 320 miles range. A 90 kWh battery pack might allow for about 350 miles range if you can keep below 208 Wh per mile. I believe that in The Real World you must allow for both Range and Performance. If instead of a 280-to-330 Wh per mile efficiency (as some have observed lifetime with a Model S), the Model ☰ can achieve even a 224-to-264 Wh per mile daily operational consumption...? Then I expect a 300 mile range in the Real World would require an 83 kWh to 98 kWh capacity. If they limit it to 194 Wh per mile as an average consumption, I am afraid it would drive like a Camry. Of course, Tesla Motors could simply 'cheat' like Volkswagen did, and just have the car refuse to go over 194 Wh per mile if its systems detect it may be going through the 5-Cycle test... It is all software controlled, after all.
While Tesla remains supply constrained, this is incorrect. Until that is addressed, nothing that they change will grow the number of purchases.
Battery tech is constantly improving by 5 to 10 percent a year while production cost decreases. So 10-20% more range for same weight and 30% less cost by time production starts. Yet total weight is down to 3500lbs. The 3 platform should be expected to have more range compared to the S.
omgwtfbyobbq
Active Member
What Tesla is doing right now is an anomaly. They don't want to give away the extra 5 KWh on the 75 KWh packs, but they probably ran out of batteries for the 70 KWh packs before they filled all the 70 KWh orders, so they are doing this as a transition. They earlier limited the 60 pack to 40 because there were not enough orders for the 40 to justify engineering an all new pack. When the initial orders for the 40 pack were filled, they dropped it from the line up.
To make just a 100 KWh pack and then software limit it down to 75 or 70 would be very poor economics. The 75 KWh pack probably has the same number of cells as the 70, just higher density. The 85/90 have two extra modules the 70 doesn't have and building the packs with the extra batteries with no guarantee they will ever make any money off the extra capacity is foolish economics.
They can put some features in there and software limit it because the cost of installing the unused tech on a relative handful of cars probably doesn't cost as much as it would to have to maintain stock of two sets of parts. This is the case with the new 48/72 A charger. It's cheaper to have one part that can be turned on later than it is to maintain stock of two parts.
They probably figured their losses from the relative few cars that pass on AP is less than the trouble stocking parts for no AP cars. Even at that they are trying to entice people who passed on AP to buy it by giving them a free trial.
Batteries are expensive and the supply is limited. Except for times when Tesla is transitioning from one battery type to another, it doesn't make sense to build the largest battery and software limit it. I expect the 70 KWh will be dropped entirely in a few months.
The decreases in costs and increases in capacity average 5-10% a year, but that's only if you look long term. Year to year it's more fits and starts. People got used to Moore's Law which was a fairly consistent progression of capability and they expect that with batteries, but there is nothing anywhere close to Moore's Law for batteries. JB Straubel has said it many times in talks.
If you're doing long term planning, you can guess in 10 years capacity will be around X and price around Y, but predicting when the next break is going to be is more problematic.
I don't see it as an advantage. I have no desire to carry around a bunch of batteries, and pay the efficiency cost of those batteries when they aren't doing me any good. If Telsa could afford to put them in my car at the price they sold it to me at, they can afford to make them active. Seems like extortion otherwise.
Thank you kindly.
Red Sage
The Cybernetic Samurai
I presume that there is a 10% 'buffer' for anti-bricking, and that EPA testing results also offer an additional 10% penalty. So, 75,000 Wh times 0.90 comes to 67,500 Wh available for use. 67,500 Wh times 0.90 is 60,750 Wh remaining, once you assume as the EPA does that you have 'spilled electrons on the floor' while filling your car in the garage. 60,500 Wh divided by 200 Wh per mile comes to 303.75 miles, which could be rounded up to 304 miles range.
As usual, I could be wrong. The percentage of the 'reserve' in the battery pack may be a bit less. The penalty for either drivetrain losses or induction losses during charging may be more. But I think this comes pretty close to what we have observed so far. In other words, I no longer count the entire expected capacity of a battery pack as being available for use.
By the way, this is also why I argue so vehemently against a 50 kWh, 45 kWh, or 40 kWh version of the Model ☰. Yeah, sure... If you could use every iota of that capacity, and tuned the vehicle to be incredibly efficient, they might achieve a range over 200 miles... 50 kWh would require 250 Wh or less consumption. 45 kWh at under 225 Wh per mile. 40 kWh at below 200 Wh per mile. Maybe. If you tuned the car to have the equivalent Performance profile of a Prius? It would not be too easy though, given what I have witnessed before.
Knowing that Tesla Motors originally expected ranges of 300-to-320 miles (Model S 85), 230 miles (Model S 60), and 160 miles (Model S 40), I'd rather not cut it so close. Because with the EPA's 5-Cycle Range Tests, the results were 265 miles (88.3% of expected range), 208 miles (90.4%), and 139 miles (86.8%) instead. If the EPA just happens to introduce a new range test, just ahead of the Model ☰ release, that is weighted in favor of ICE, Tesla Motors may not officially reach their intended minimum range. That would be bad.
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SageBrush
REJECT Fascism
I'm not sure about the EPA methodology but it makes sense to include the charging losses when the number is 'electricity used per mile,' but not when calculating range. It would also be interesting to know whether EPA uses the battery nominal capacity or the usable SOC.
I'll have to see whether EPA has numbers to reflect each situation. Or maybe the EPA always includes charging losses and does not account for unused SOC. If both are ~ 10% then the final number is fairly accurate, at least for Li-x.
Addendum:
I checked the 90D Mx. From fueleconomy.gov,
MPGe city 90 Highway 94, average 92
Consumption: 37 kWh/100 miles
92 MPGe average = 2.73 miles per kWh
= 36.3 kWh
So within a rounding error*, EPA uses the same assumptions for each number. The sticker says 257 miles range. If based on 37 kWh/100 miles, it implies 95 kWh usable.
My GUESS, then for range:
highway consumption
Charging losses
Nominal capacity rating
*
94.5 MPGe highway
94.5 miles / 33.7 kWh
= 2.8 miles / kWh
= 91.7 kWh for EPA range of 257 miles
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Red Sage
The Cybernetic Samurai
Almost, not quite. Notice my saying above, "spilled electrons on the floor"...? The EPA does count the charging losses while filling at home. Their calculations are primarily financial in nature. That's why the numbers don't match. The 37 kWh per 100 miles, or 370 Wh per mile driven, is far worse than the observed 280 Wh per mile to 320 Wh per mile that Tesla Model S owners often report. That difference is the charging losses.
320 Wh divided by 370 Wh comes to 86.846~%. In other words, for every 100 kWh you put into the car at home, the EPA assumes you have paid for 115.62 kWh. Their calculations are 'electricity paid for per mile'... not how much is actually USED by the car. This is, in my opinion, rather unfair because no one presumes that anyone is spilling gasoline or diesel fuel on the ground while filling an ICE. They count the capacity IN THE CAR instead.
Therefore, those who only use about 280 Wh per mile in their car are even worse off as far as the EPA is concerned. Because their 370 Wh per mile metric means you buy 132.14 kWh for every 100 kWh you put in the car. That is pure, unmitigated [BORSHT].
This isn't just a financial calculation. The electricity drawn from the wall (and thus including charging overhead) is the energy actually used and thus the CO2 and other pollution emitted to charge your car. Including the charging overhead is important because it encourages car makers to design efficient battery chargers. And let's get real... nobody spills a gallon of gas on the ground when they add 10 gallons to their tank at the gas station.
As for actual EPA range estimates, I don't think that is calculated. I believe the test procedure is to charge the car, let it sit a few hours, and then drive it through the test cycle until the car can no longer keep pace with the required speed and acceleration of the test.
Red Sage
The Cybernetic Samurai
Going up the line and including such things is unfair if the same thing is not done for petroleum fuels. The way this is set up currently, it is a disadvantage to EVs. If the same is done with petroleum fuels, the advantage to EVs is multiplied instead.
Miles per gallon gasoline equivalent - Wikipedia, the free encyclopedia
SageBrush
REJECT Fascism
This link is pretty good, and if I am reading correctly says that charging losses are not considered in range, but instead
- (UDDS+HWFET) in energy/mile while driving * 5/7
- Usable total battery capacity
FlatSix911
Porsche 918 Hybrid
SageBrush
REJECT Fascism
My problem with the EPA is that they cannot decide what to be when they grow up (money Vs emissions,) and the attempt to appease ignorant Americans who have no idea what a kWh is but have no intention of buying an EV is nonsensical.
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