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Discussion in 'Model S: Battery & Charging' started by Discoducky, Jun 20, 2012.
EPA rates Tesla Model S for 89 MPGe, 265-mile range with largest battery pack
89... I'm no expert but when I was doing some calculations (1 gallon of gas in 33 kwh of energy is it?) I got much higher. Though I guess that was using a higher real world range too.
*edit* someone can correct me if I'm wrong, but if the number I was working with (33 kwh == 1 gallon of gas) is correct, then an 85 kwh pack that goes 265 miles on a charge uses up .32 kwh per mile. So with 33kwh in a gallon, you'd get 33 / .32 = 102ish, closer to 103 mpge...
Fueleconomy.gov - 2012 Tesla Model S
When they (Fueleconomy.gov - 2012 Tesla Model S) say
Cost to Drive 25 Miles $1.14
what cost/kWh are they using? They don't seem to say.
I don't get that rating at all!! Shouldn't city be much MUCH higher as all that stop and go means more energy back into the battery int the Model S with active regen?
2012 Tesla Model S: EPA Range Of 265 Miles, 89 MPGe Efficiency
It's the exact numbers that Elon and JB said in their blog post on May 9th.
Model S Efficiency and Range | Blog | Tesla Motors
And DSM - at the bottom of the EPA page they say the price is .12 per kWh.
Doesn't 89 seem low, compared to the 99+ of Leaf and others?
The EPA must have been flooring it!
Still, this seems way low. According to this it's 38kWh/100 miles. So the 40kWh battery might only go 110Miles? I was expecting it to be closer to 130Miles. Also, I don't see how city and hwy #'s are that close.
I do like the $$$ savings though!
And, given 38 kWh/100 miles, how does the 85 kWh pack give 265 miles? Isn't it only ~223 miles?!
Regardless of whether the number is right or wrong, remember the Model S is *much* bigger than the Leaf. Much more battery = heavier than the Leaf.
Still, not too shabby given 0-60 in 4.4sec...
Sounds about right. The Model S is a heavy car with huge wheels/tires compared to the other EVs on the market. 89 MPGe is very good for this car.
City efficiency isn't higher because of the high weight. Highway fuel efficiency isn't higher because of the big wheels/tires.
Also remember that the kWh/mi ratings from the EPA are from the wall and include charging losses. So according to the EPA if you put 37 kWh into the car, you'll go right around 100 miles. The LEAF where you can only stuff 24-25 kWh into it from the wall, will do about 73 miles freeway. So Telsa's estimate of 265 miles EPA range for the 85 kWh Model S is about right. The 40 kWh Model S should have about 120 mile range.
Anyone else notice that the EPA site lists the Model S as having a 83 kWh battery, though?
Yeah. Surely data entry error.
Remember that their numbers are wall to wheel. So 38kWh if the charging is only 90% efficient, only puts 34kWh into the battery.
Even if the charger is 90% efficient ( I made that up, I don't know what it is ) there is likely additional overhead due to cooling.
I don't want to get too far off topic here, but isn't that really "unfair", given that MPG is tank to wheel?
Edit: I mean in a sense when comparing to an ICE.
The article also makes a pretty big error is stating that the Model S has the worst MPGe rating of any electric car. The Coda Sedan got 73.
Not when the purpose of the number is to determine your fuel cost.
Why would an American consumer be interested in that?
The efficiency number (38kWh/100miles) includes charging losses. You can't use that number with the battery capacity to figure out the range. That's why the math doesn't work out if you just divide battery capacity with the range. From the EPA page they give the battery capacity only a 83kWh rating (maybe that's the usable capacity).
Anyways, 83kWh/265miles = 31kWh/100miles. So charging efficiency's only about 31/38 = 81.6%.
Anyways, the 89MPGe is what Elon said in a recent conference call. They are trying to get a better number by improving the charger.
Thanks, stopcrazypp. I've got to digest your detailed post on that other thread.