Tesla Model S EPA Ratings For 2015


New base version of Model S - 70D.

New base version of Model S – 70D.

Tesla has finally pushed past the 100 MPGe mark with the release of its Model S 70D.

What’s interesting is that the 70D, likely heavier than the 60 kWh Model S that it replaces, is actually more efficient than the outgoing model.  This is probably due to the dual-motor setup.

Another point of interest is that, back in 2012 when Tesla first launched the Model S, the most efficient version of the car, the 40 kWh, had a combined rating of only 94 MPGe.

Seems like Tesla focuses on yearly efficiency improvements too.

2012 Tesla Model S EPA Rating

2012 Tesla Model S EPA Rating

Source: Electrek

Categories: Tesla

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45 Comments on "Tesla Model S EPA Ratings For 2015"

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On the next couple of tears when the Model S will become an instant modern classic, I wonder how valuable or sought after would the old 40kWh versions would be.

The rarity of the model isn’t everything (you won’t see 2.7L Plymouth Barracudas fetching big money at Barrett-Jackson), how sought after it was plays a much bigger role. If you are looking to pick up a Tesla as a collector’s item, you want the P85 Signature edition.

With the old glossy deep-red paint? I’d kill for that.

I’d understand now. It’s a novelty thing really and they couldn’t rapid charge. If they didn’t have a 40kWh badge, then what’s to gloat about?

Note that it’s identical to S/60 except for a software change that limits battery capacity of the 60KWh pack to 40KWh.

Due to lack of demand no real 40KWh versions were ever made.

Can anybody please explain to me how the MPGe can increase without the rated range also moving up?

The “D” rated range was always based on the higher efficiency. The historical numbers were for the RWD versions.

Agree. If 85 went from 94 to 100MPGe then why does EPA range only increase from 265 to 270?

I would imagine that it has more to do with the EPA testing.

Probably due to a few percent more efficient charging. At a given price point, we see better power transistors come out year after year.

Keep in mind that using a MPG rating is a bit lopsided. A more reliable method would be gal per 100 miles (similar to Europe’s L per 100 km). As you use less and less gas, your mileage gets higher and higher, BUT small changes in fuel use translate to huge swings in MPG. For example, the Mazda 3 I used to drive before our Prius used to get me about 29 MPG while our Prius got us about 45 MPG (it’s worth nothing that the Mazda was 3 MPG under EPA rating while the Prius was bang on). That looks like a huge difference until you convert to Gal per 100 miles. The Mazda was 3.4 Gal per 100 miles while the Prius was 2.3 Gal per 100 miles. So, 1.1 Gal difference translates into a 16 MPG difference. It LOOKS a lot different in MPG but when you calculate actual gas burned, it isn’t really a big difference. Granted, the Model S doesn’t burn gas, however, because the EPA uses MPGe, the same high degree of variability with lower levels of energy consumption still exists. You can actually see it by looking at the kWh/100 mile numbers. Only… Read more »

By increasing the efficiency of the on-board charger. This improves the EPA rating for energy use (MPGe) without changing the Wh/mile used for propulsion, or the range on a full charge.


“The EPA portion of the vehicle Monroney label now displays an average of the two estimated ranges when charged in these two different modes.”

The MPGe rating is not impacted by different charging modes. It is a measure of efficiency only, regardless of battery size.

The Range rating is impacted by different charging modes that may only use part of the total battery capacity. Range is a measure of both efficiency and battery use.

The ultimate example being the Volt. It only used around 50% of the battery when it first came out. Now with the 2016, they have only slightly increased battery size, but greatly increased Range. They are doing this by using a larger percentage of their battery pack.

You cannot automatically extrapolate what the range will be by simply comparing MPGe and battery size. What percent of the battery is used in each charge mode has to also be factored in.

OK. So there is no efficiency improvement as such in a particular model. It’s that newer more efficient models have been launched.

Yes Stephen agreed. There is no linear correlation between MPGe and rated range of 85, 85D and P85D models. MPGe/Rated range for P85D is 93/253 versus 89/265 for the 85. MPGe is lower but range is higher for 85. How come? Doesn’t make sense.

Better charger, better epa mpge. Range the same..

I was going to say you are wrong but you are right. I looked up the plain 2012 85KWH Model S and the plain 2015 85KWH Model S and they have the exact same MPGe (89 Combined city/highway).

I guess the D really does help on efficiency.

I wouldn’t say for sure that a 2015 85kWh is not more efficient than a 2012 85kWh in real life. EPA allows the manufacturer leeway in terms of keeping older numbers if there haven’t been very big changes (esp. if the number they are keeping is a lower number like in this case).

I suspect Tesla just kept the old numbers and didn’t want to retest and re-certify the cars. I believe the 2015 Volt did the same thing.

Nice to see Tesla cross the 100MPGe market with the 70D. I think it is nice to be able to tout a triple digit MPGe in order to emphasize the efficiency of EVs. (And yes, the MPGe number is nice because it allows people to make comparisons to gas cars. But they give you the KWH/100 miles in the small print too.)

I wonder why the 85D is lower city but higher highway MPGe than the 70D? Lower city was to be expected (heavier) but why higher highway? Real, or test artifact?

Also, the 85D was already 100 MPGe combined, so it had the magic three digits for the casual punter (who is the only person this kind of magic number matters for).

Well, apparently they really do clever stuff with the two motors to maximize efficiency. Perhaps when you are cruising on the highway, it turns off the big rear motor and just relies on the smaller front motor to pull you along.

Also, they say that they do things like switch between the two motors depending on their temperatures to keep the motors operating at their most efficient. If one motor is too hot, turn it off for a while and let it cool down.

But I’m just guessing, it would be nice to know the real reason.

Because since EV’s don’t need transmissions as we know them it allows two different final drive ratios to be used on Front / Rear axles. One optimized for lower around town speeds and the other for freeway speeds allowing each respective motor to remain in it’s sweet spot depending on speed / throttle / etc. Pretty slick actually

If they are doing what you just described, that shows that EVs do need at least two gears.

No, they don’t NEED to two gears. It shows that with the AWD system, they HAVE two gears without needing any sort of clutch or automatic transmission which loses efficiency.

Wow, I NOW understand now the AWD system really helps on efficiency. Thanks Daniel!

Like I suggested some time ago. This is brilliant. They tried a two speed gearbox, and it didn’t hold up. Their single speed gearbox had problems too, trying to haul over two tons to 60 mph in under 4 seconds. Splitting the load between two gearboxes with different ratios solves both problems.

Hmm . . . so do you think this helps solve the ‘milling sound’ and eventual replacement of many of the Model S motors?

Yes. That is what I am talking about. The other option would have been to stick to more reasonable controller settings. But lethal acceleration is what sells, not saving energy…or our grandkids future.

Spec — Dual motors also provide a new “sleep” feature to improve efficiency. It is documented here for the 85D and P85D, but this was before the 70D:

“Values for 85D and P85D are pending final confirmation from the EPA and use new dual motor torque sleep control software available by the end of January 2015.”


I have no idea if the 70D has this feature or not. I couldn’t find that info.

As far as I know (and I’ve looked fairly hard) the speculation that Tesla uses different gear ratios front and rear has never been confirmed either by a source within Tesla, nor by testing or teardown. It’s a fun idea, but so far, no more than that.

Yes, but the 70D and 85D are basically the same car. Both are dual-motor, and both use small motors front and rear. The only substantial difference (AFAICT) is the size of the battery pack.

Both 70D and 85D use the same “Next Gen” motor, front and rear.

The 85 uses the older motor still, and the P85D uses the older motor in the rear, and Next Gen motor in the front.

The new motor has higher efficiency.

Yes, exactly. What I was wondering about is why, with lighter weight and the same pair of “next gen” motors, the 70D lacks four miles of highway MPGe compared to the 85D in the EPA ratings.

Low city readings have to overcome inertia (mass * acceleration forces), due to stop/go driving patterns. This requires large demands and variation in the amount of horsepower (HP) used. (eg: 0…30 mph in under 2 seconds, and regen is less than 100% efficient).

On highway the forces on a vehicle are constant, thus inertia forces are almost zero; meaning only 30-40 HP is needed to maintain speed on level ground.

Sure — but why would the 85D have a better rating than the 70D? Given the only difference between the two is the size of the battery pack, one would expect the highway rating to be the same, or infinitesimally higher for the 70D due to the lesser mass while accelerating to highway speed.

MPGe = pointless/useless

Absolutely not. It highlights the efficiency advantage of EVs over ICE. Don’t use it if you don’t want to but it is a useful number.

The problem is it confuses less informed people into thinking the car is a hybrid and uses gas. I agree it is pointless. It doesn’t show efficiency advantage either- it shows price advantage, but not even that as it requires assumptions about the price of gas an price of electricity, and is more than offset by the increased price of the car. Best if the government stopped wasting money on this.

MPGe in a pure EV is a direct measurement of how many miles the car can go on 33.7 kW-hrs of electricity.

What is worthless about that?

It is a way to compare efficiency between EV’s regardless of actual battery size, that is expressed in units that show how much more efficient electric motors are than ICE motors.

You charge an EV with 33.7 kW-hrs of electricity, and you see how far you can go. It is the same as filling a gas car with 3.78541 liters of gas, and seeing how far it will go (That’ called MPG). If the units of measure are making it hard to understand for some, that is an education issue. Like teaching Americans the metric system.

Nix asked:

“MPGe in a pure EV is a direct measurement of how many miles the car can go on 33.7 kW-hrs of electricity.

“What is worthless about that?”

Well, the most significant problem is that the testing procedures are such that the ratings don’t reflect the efficiency of the car, so yes they are indeed worthless. Just look at and compare the MPGe ratings of a few, and you’ll see what I mean. The MPGe ratings are all over the map.

But aside from that, it’s ridiculous to try to spoon-feed car buyers numbers suggesting that powering an EV is actually comparable to powering a gas guzzler. It’s a false equivalency. It would be as if in the early days of the horseless carriage, sellers of motorcars rated their gas consumption by comparing it to how many bales of hay a horse eats per week.

Electricity is rated in kWh. Drivers will need to learn to think in terms of consuming kWh as they drive, and not in terms of consuming gallons of gasoline.

Lensman — The EPA MPGe test for pure EV’s is measured in kilowatts. Then it is translated into MPGe for publishing because that is what the mass market demands. They are very much accurate measurements between different pure EV’s, as they are the exact measure of the number of kilowatts consumed when driven on the EPA test cycle. There is no magic or mystery about the measurements that are all done in kilowatts. They take a fully charged car, drive the EPA test cycle, then recharge it and measure the kilowatts used to recharge it. The fact that there are variances simply proves that some EV’s are more efficient than others at both driving and recharging. (Consider CODA, for example — lousy MPGe because it was a horribly inefficient car). You suggest that: “Electricity is rated in kWh. Drivers will need to learn to think in terms of consuming kWh as they drive, and not in terms of consuming gallons of gasoline.” Well, the mass market strongly disagrees. The EPA conducted a substantial number of study groups of mass market car buyers. These study groups OVERWHELMINGLY said they didn’t even know what a kilowatt was! Even worse, when those who… Read more »

From EPA Model S 70 data (above) … “cost to drive 25 miles: $0.99”.

Considering ‘average new vehicle’ sold in 2015 will get ~25 MPG … this equates to driving (city) on $0.99/gallon fuel. Of course with a Model S70, driving on supercharged highways is free. (not factored into EPA savings, and added 5-10% value over that listed).
🙂 🙂

Better charger efficiency, better EPA mpge rating. But same range…

“The EPA portion of the vehicle Monroney label now displays an average of the two estimated ranges when charged in these two different modes.”

If the charging modes in the 85D and the 70D are programmed differently, the range numbers will be different, regardless of what the efficiency is for each car.

In other words, the range and the efficiency are NOT both directly tied to the battery size.

Any charging modes that reduce HOW MUCH of the batter is used will impact the EPA range number, but will NOT impact the MPGe number.

Any attempt at trying to directly extrapolate MPGe from the EPA range rating is false. The charging modes available must be factored in.

Does anybody know if the 70D has a “Range Mode” for charging? I haven’t been able to determine if it does or not.

Tesla has eliminated the “Range” mode, in favor of the driver using a slider to determine how full he wants the car to charge. So now you’re not locked in to either 80% or 100%*; you can choose any percentage you want.

This was one of Tesla’s wireless software upgrades.

*altho when the gauge says 100%, it’s actually only 95%. The percentage should be thought of as the fraction of how full Tesla allows the driver to charge the battery pack, not the actual percentage full the batteries actually are. Tesla babies its battery packs by not allowing them to ever be charged to 100%.

Interesting. That REALLY complicates comparing EPA Range ratings with MPGe.

Tesla has to somehow average in that. Either that or they are using it as a dodge from having to average anything, by claiming that they don’t have multiple charging modes….

Very interesting.