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gg_got_a_tesla
Model S: VIN 65513, Model 3: VIN 1913
Red Sage
The Cybernetic Samurai
You just restated the very bias I was speaking of... What matters is the results, not the theory. When the EPA created the algorithm for determining 'efficiency' for EVs it built in weight as a factor in an unfair manner. It was based upon the presumption that all EVs would be teeny, tiny, dinky, wimpy, impractical, low range, econo-boxes -- instead of being 'REAL cars'. The same sort of bias was used for determining 'Green Cars' for LEEDS certification. As a result, the Tesla Model S isn't listed among them, but multiple gas burners are... Too often such things are determined by people with an extremely narrow focus, instead of looking at all the possibilities. No one expected an automobile manufacturer to ever put a relatively massive battery pack in a car, so they didn't allow for the eventuality in their calculations. That is an inefficient process of evaluation, not an inefficient means of making a vehicle.
What on Earth are you talking about?
The test is the same for conventional and plug-in cars: run test cycle, measure fuel used to fill up tank, adjust numbers because you're bench testing.
I'm sure twin-BEV owners on this site will assure you that other BEVs are indeed more efficient than a Model S in real world conditions that mirror the test cycles. And I'm sure people can equally point out that EPA testing of conventional cars also have problems with real world conditions that don't mirror test cycles, principally that they help boxes, hinder small engines and hinder diesels.
Trev Page
Member
I'm fully prepared for a Model 3 to be upwards of $50K by the time you add a few options, possibly a bigger battery pack. I'm figuring $35US is going to be about $40K CAD after exchange to be on the safe side then another $10K in options and destination charge. Deduct a downpayment consisting of money saved and proceeds from the sale of my current car, add tax and deduct Ontario's $8500 rebate (assuming its still there) results in a net price of around $32K all in. Perfectly affordable over 5 years financing. And the best part is no gas!! My current SUV if I kept it would cost me $29K over 9 to 10 years in gas alone considering the milage I do. Model 3 is going to be pretty much a no brainer for me. I don't lease, I finance my cars because of the milage I do.
I have my deposit ready
I have my deposit ready
Red Sage
The Cybernetic Samurai
The weight of the car should not matter. What matters is what it does. If someone manages to make an 8,000 lbs two-seater that gets 250 miles per gallon, has a twenty-five gallon fuel tank, and can be driven over 6,000 miles without refueling it should not be given a lower efficiency rating than a car that weighs 3,000 lbs, seats four, gets 40 miles per gallon, and has a ten gallon tank. That would be ridiculous.
The EPA is giving cars that have a maximum of 76, 82, 84 miles of electric range an MPGe rating of over 100, but rated the Model S 85 -- which they confirmed has a range of well over 200 miles -- at 89! SEE THE RESULTS YOURSELF. Neither of the cars that have that MPGe rating even store enough energy in their batteries to match the 33.7 kWh the EPA says is the basis of the rating. That is what I'm talking about!
MPGe Rating has nothing to do with range or with kWh of battery capacity. It has to do with efficiency at turning power into miles traveled or Watt/hours per mile. A Leaf has a higher MPGe rating because it gets more miles per kWh than the Model S.
By your reasoning adding a larger fuel tank to a car should get it a higher EPA MPG rating since it has more range. That makes no sense whatsoever.
Agreed. The Leaf is much more efficient than the Model S - real world. That is not just because of weight directly. Higher weight begets larger tires which have more rolling resistance. The Model S is not particularly efficient. That is what MPGe measures. That is reality and a big deal. The Model 3 will probably be much more efficient.
Now what I don't know is did they hit the brakes on the Model S every time. What did they set regen on. I could see the Model S getting punished (fairly or not) based on no extra regen when you hit the brakes. Certainly the Leaf and probably every other EV increase regen when the brakes are used. The EPA probably hits the brakes when a lot of Model S drivers don't regularly hit the brakes. But I'm sure that the EPA stays conventional and doesn't modify their driving for Model S - which is fair.
Not driving the vehicle properly is not really fair, but since the regen is quite obvious when you lift off the pedal my guess is they did use it, and regen is still in effect even when you use the brakes.
Model S is particularly efficient for it's power/size/weight. People with experience of both vehicles report that the differences is surprisingly small.
At the time the test was done Model S had only one settings for the regen - full regen.
Red Sage
The Cybernetic Samurai
Dude. Did you actually look at the link I posted? The one that goes directly to the EPA's website, FuelEconomy-dot-gov...? The one that shows "EPA Fuel Economy" as the formula "1 gallon of gasoline=33.7 kWh"...? The one that specifically shows the range rating of multiple vehicles, and their MPGe based upon calculations for "kWh / 100 mi"...? This is EXACTLY what it stands for... it is not MY reasoning behind these calculations, but the EPAs... And they are BIASED in FAVOR of smaller electric vehicles that can NEVER achieve the range that their MPGe intimates.
Canuck
Well-Known Member
My cabin is 300 km away over two mountain passes. My Leaf can't take me there, or if it could, it would be an enormous task with a lot of wasted effort. My Model S can take me there with range to spare. So to me, the Model S is far more "efficient" than the Leaf:
ef·fi·cient: (especially of a system or machine) achieving maximum productivity with minimum wasted effort or expense.
stopcrazypp
Well-Known Member
This confuses a lot of people. The MPGe figures measures the kWh that comes from the outlet and has nothing to do with the capacity of the battery in kWh (except indirectly). This means it includes charging losses (which varies depending on the car). That's why none of the MPGe figures match up with the range and capacity figures (usable or otherwise).
For example, the Leaf gets EPA rated 30kWh/100 mi (114MPGe). It gets rated 84 miles of range, with a 24kWh nominal battery and 21kWh usable.
24kWh nominal/84 miles = 28.5kWh/100 mi.
21kWh usable/84 miles = 25kWh/100 mi (this is the actual "battery-to-wheel" efficiency)
Note how neither number matches the MPGe (and thus the kWh/100mi) rating. This has to do with the charging losses that I mentioned. You can however calculate from the "usable" number vs. the EPA number that the charging efficiency of the Leaf is ~83%. You also can calculate it took 25.2kWh to fully charge the Leaf according to EPA procedures.
http://www.fueleconomy.gov/feg/Find.do?action=sbs&id=34699
From other thread, the "usable" capacity of a 85kWh Model S appears to be about ~81kWh (going below the point where the car says "0" range left). Given 265 mile of EPA range, that would appear to be a 30.6kWh/100 mile "battery-to-wheel" efficiency, which means the Model S is less efficient than the Leaf on the EPA cycle (as expected).
http://www.teslamotorsclub.com/showthread.php/30539-Real-Usable-Battery-Capacity
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The fact that a Leaf's range doesn't match its MPGe rating just means it has a tank equivalent to less than a gallon of gas. If a gas car gets 20 MPG, and has a half gallon gas tank, it has 10 mile range, but still gets 20 MPG.
Most gas cars have significantly larger tanks because gas is lighter than batteries for a given energy amount, so the amount you have to haul around increases less quickly relative to the extra energy than it does with a battery system.
Physics has a bias against larger cars. You could look at specific efficiency energy / (mass * mile), which is how a lot of things are compared. The miles per gallon rating for a train would be terrible, but the miles per ton mile are fantastic. But this sort of comparison doesn't work for cars, what you should really look at is energy per person mile. If a car is regularly used to move two people, then it is more efficient at moving people around than if it only carries one passenger. The model S does have the two kids seats that the model 3 probably won't have, so there might be a difference in average number of passengers. But ultimately, that isn't what people care about, what people want to know is how much energy they have to put in the car for every mile they want to travel, that is why we look at MPG, and why MPGe is formulated similarly.
Most gas cars have significantly larger tanks because gas is lighter than batteries for a given energy amount, so the amount you have to haul around increases less quickly relative to the extra energy than it does with a battery system.
Physics has a bias against larger cars. You could look at specific efficiency energy / (mass * mile), which is how a lot of things are compared. The miles per gallon rating for a train would be terrible, but the miles per ton mile are fantastic. But this sort of comparison doesn't work for cars, what you should really look at is energy per person mile. If a car is regularly used to move two people, then it is more efficient at moving people around than if it only carries one passenger. The model S does have the two kids seats that the model 3 probably won't have, so there might be a difference in average number of passengers. But ultimately, that isn't what people care about, what people want to know is how much energy they have to put in the car for every mile they want to travel, that is why we look at MPG, and why MPGe is formulated similarly.
I would just say that efficient in reference to energy has a slightly different meaning. The Model S can be much more productive than the Leaf. But in terms of energy use and what MPGe is measuring, it is less efficient. Even in terms of energy, efficient can be confusing. For example an electric hot water heater is much more efficient than a NG one. Until you take into account generating electricity. As such, an EV will always be more efficient than an ICE, but the comparison isn't fair.
What is fair is that a Leaf is more efficient than a Model S when the comparison is getting 2 people 20 miles away. If you are transporting 6 people, obviously the Model S wins. For the vast majority of driving, the Leaf is the more efficient tool. That is what the EPA is measuring. And they are talking energy efficiency not any other type of efficiency. Not a big deal but it is what the EPA is measuring. The EPA isn't measuring how practical the car is, how comfortable the car is, the range, or how powerful the car is. The EPA is measuring Energy Efficiency!
Of course the i3 is even more efficient.
The EPA doesn't account for vampire losses. The Model S is much better than it was but still is higher. I am unclear if the EPA accounted for battery TMS energy use which is obviously higher on the Model S. I suspect they didn't which again favors the Leaf. So the real world difference is actually quite significant - beyond what the EPA measures. Does the EPA charge the Leaf at 120V and Tesla at 240V? Makes sense since that is what the cars come with. Charging the Leaf at 240V (which most owners do) decreases the charging loss again favoring the Leaf over the EPA (if they tested it at 120V)
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I don't believe that comparison is fair.
Model S was their first car from the ground up with little infrastructure in place.
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