Confused About EPA Range vs Rated Consumption

[Master_Aryon]

I’ve been driving a Tesla Model Y for a bit now, after two years with a Model 3, and I’ve noticed something that doesn’t quite add up when looking at range calculations. The efficiency on my Y is great, actually better than my old Model 3 in certain conditions, but when I try to do the math on EPA range versus rated consumption, I’m scratching my head.

Here’s the situation:

• I drove 200 km at 120 km/hr in near-freezing temps and logged 200 Wh/km, which I think is pretty decent.
• The rated consumption for the Y is 170 Wh/km, but with a 75 kWh battery, that only gives around 460 km of range, not the 520 km the EPA rating claims.
• For the Y to hit 520 km of range with a 75 kWh battery, the average consumption would have to be closer to 140 Wh/km, which seems way off from the rated 170 Wh/km.

I get that EPA ratings are based on mixed driving cycles and ideal conditions, but how does Tesla reconcile the 170 Wh/km rating with the EPA range? Does anyone know if there’s a different calculation or assumption being used here? Or am I just missing something obvious?

 

[SherlockHolmes_67]

That is insightful! It is evident that the energy graph's rated energy consumption does not always accurately represent actual efficiency. Actual energy consumption can be affected by variables such as temperature, driving conditions, and battery buffers.

Understanding the performance gap is made easier by your comparison of the rated and actual energy consumption rates. The Model Y's higher rated energy consumption but lower real-world consumption may be explained by a larger usable battery capacity than anticipated.

I think examining the Model Y's battery chemistry and thermal management systems in greater detail will help determine whether they play a role in this discrepancy would be intriguing. I'd love to know that.

 

[rodthecolaguy]

I’ve been driving a Tesla Model Y for a bit now, after two years with a Model 3, and I’ve noticed something that doesn’t quite add up when looking at range calculations. The efficiency on my Y is great, actually better than my old Model 3 in certain conditions, but when I try to do the math on EPA range versus rated consumption, I’m scratching my head.

Here’s the situation:

• I drove 200 km at 120 km/hr in near-freezing temps and logged 200 Wh/km, which I think is pretty decent.
• The rated consumption for the Y is 170 Wh/km, but with a 75 kWh battery, that only gives around 460 km of range, not the 520 km the EPA rating claims.
• For the Y to hit 520 km of range with a 75 kWh battery, the average consumption would have to be closer to 140 Wh/km, which seems way off from the rated 170 Wh/km.

I get that EPA ratings are based on mixed driving cycles and ideal conditions, but how does Tesla reconcile the 170 Wh/km rating with the EPA range? Does anyone know if there’s a different calculation or assumption being used here? Or am I just missing something obvious?

Curious if Where did you get those numbers?

 

[pompomlork]

It's true, the math doesn't always seem to line up perfectly between rated consumption and EPA range. You're right, 170 Wh/km with a 75 kWh battery should give you around 440km, not the 520km EPA rating. The key is that EPA tests use a specific set of driving cycles and conditions, including lower speeds and more city driving, that are designed to simulate typical driving.

They aren't necessarily representative of real-world highway driving at 120 km/h in near-freezing temperatures, which as you've seen, will use more energy. Tesla, and other manufacturers, likely use a different, more complex calculation for the EPA range that takes into account those specific test cycles and conditions. It's not just a simple division of battery capacity by rated consumption. So, while your 200 Wh/km at highway speeds is perfectly reasonable, it's not directly comparable to the number used to derive the EPA rating. Think of the EPA rating as a best-case scenario under ideal conditions, not a guarantee for every type of driving.

 

[Evholic_24]

I think there is some confusion with how Tesla is displaying rated consumption versus actual energy use.
The early 2020 Model Y had a rated consumption of around 153 Wh/km based on a 77.8 kWh usable battery.
If you are seeing 170 Wh/km as the rated value, I wonder if that's the real-time consumption and not the rated line on the energy plot.
Tesla’s UI can be a bit tricky with these labels.