After driving conventional gas vehicles for long time and since Tesla does not use gas but rather is fully electric and solely relies on a single battery unit, I was having difficulties trying to understand battery range estimations shown in the Tesla’s instrument panel and the Energy App. Both displays should give a better idea about how long does battery last on Tesla. There was confusing difference between Rated Range versus Ideal Range. How the EPA mileage is calculated. Finally, the range anxiety was bothering me for at least a year. In this blog, I would like to share my secrets how to quickly estimate Tesla Model 3, Model S and Model X range including EPA range by understanding battery consumption rates and range estimations in instrument panel and hopefully reduce and overcome the range anxiety.
Tesla Remaining Battery Energy Estimate
How long does battery last on Tesla Model 3, Model S or Model X? Tesla uses a single battery unit installed underneath the vehicle. Tesla’s Energy Display lets you control how you want to see the remaining energy or range in the battery. The choice is between:
- percentage of battery energy remaining
- estimate of the distance
Both are digital instrument displays versus analog instrument displays. Analog instruments are great at showing continuously changing trends. The digital displays are good at showing discrete values versus trends.
In the traditional ICE vehicle with the analog instrument showing gas levels, it is very easy and fast to see the remaining gas tank levels and its trends. With digital displays, the trends are not possible to sense.
Percentage of Battery Energy Remaining
In Tesla instrument panel, the estimated percentage of battery remaining shows values such as 50% or 75%. You could use it to quickly detect the remaining range in percentage.
I used this setting for few months but did not find it very useful. The battery image with the green bar in the instrument panel does show at a glance how much energy or distance you have remaining and is similar to the analog display.
Tesla Estimated Driving Distance
When the estimated driving distance is selected in the Tesla energy display, you can choose between Rated or Ideal.
Ideal Estimated Distance
The Ideal setting is not very useful by definition and from my experience. It shows range in ideal driving conditions based on driving at a steady speed of 55 mph on a flat road, and using no additional energy such as seat heaters, air conditioning, etc. These conditions are almost never occur due to weather in North East is not predictable and could range from extreme heat outbursts in summer and sub zero temperatures in the winters. Driving on flat roads is also not an option. Driving at steady 55 mph is at all not possible. I am not sure why Tesla is even offering this as a choice. This is confusing and not useful.
Rated Estimated Distance
The manual says that Rated setting in the energy display should display estimated distance based on the EPA rating. But what is the EPA rating and what is it based on? The manual does not specify.
The Energy App in the instrument panel and in the touch display shows the real time feedback on the amount of energy used or being gained by regenerative braking. The projections and estimates are made using the data points over last 5, 15, or 30 miles.
I found that the distance estimates when using the Average setting is the most accurate especially over 15 or 30 miles.
However, the remaining distance estimates in the driver instrument display when using the Rated mode do not always match with the distance estimates in the Energy App. Both show estimated distance but based on what?
Battery Consumption Rate
The secret is in the middle gray line in the Energy App. This line specifies the average battery consumption rate in Wh/mi which used in calculating average Rated estimations. The magic number is 300 Wh/mi. This number is not documented in the Tesla’s manual even though the average estimated distance displayed in the driver’s instrument panel is based on the Rated value using this specific consumption rate.
How does this average consumption rate help with battery range estimations?
This is how it helps me:
I observed that if driving Tesla Model S at 300 Wh/mi consumption level, you will be very close to achieving the Rated estimated driving distance displayed in the driver’s instrument panel.
If driving at consumption levels above the magic 300 Wh/mi mark such as 350 Wh/mi or 400 Wh/mi, you will drive for lesser distance than the displayed estimated distance.
If driving at consumption levels below the 300 Wh/mi (250 Wh/mi and etc), you will achieve an even higher mileage than estimated Rated distance.
If you heard of Hypermiling concept and want to achieve hypermiling in Tesla, your goal should be to drive well below the rated 300 Wh/mi.
The combination of both Rated estimated remaining distance in the bottom left corner and the average current Consumption Rate in the Energy App in the instrument panel give me enough real time information on how much energy is left to cover a certain distance. This also helps to decide when driving style adjustments are needed to achieve the Rated distance.
Especially in winters, when consumption rates are normally at or much higher than 300 Wh/mi, you quickly appreciate that you will not be able to drive the complete Rated distance.
In summers, when consumption rates stay normally at or below 300 Wh/mi, you feel much more comfortable about achieving the rated ranges.
EPA Range Estimations
It seems that the same battery consumption rate value of 300 Wh/mi is used to produce the EPA ratings for Tesla cars with corresponding battery capacities. For example:
Tesla with 60 KWh battery will have the estimated 60,000 Wh / 300 Wh/mi = 200 mi average estimated range.
Tesla with 75 KWh battery has the estimated 75,000 Wh / 300 Wh/mi = 250 mi average estimated range.
Tesla with 90 KWh battery will have the estimated 90,000 Wh / 300 Wh/mi = 300 mi average estimated range.
Finally, Tesla with 100 KWh battery will have the estimated 100,000 Wh / 300 Wh/mi = 333 mi average estimated range.
The current and latest long range 2019 Model S is rated at 370 mi EPA. Tesla does not anymore specify the battery capacity on their Web page. But we can easily estimate the battery capacity using the average consumption rate:
370 * 300 Wh/mi = 111,000 Wh or 111 KWh battery
This means that Tesla is already producing batteries with over 100 KWh capacity and at a cheaper price than 90 KWh several years ago.
The latest 2019 Tesla Model 3 Long Range is rated at 310 mi but no mention of the battery capacity. How many KWh is in Tesla Model 3? This can easily be calculated as follows:
310 mi * 300 Wh/mi = 93,000 Wh or roughly 93 KWh battery
Tesla SUV, Model X long range has 325 miles published EPA range as published on the Tesla Web Site. How many KWh is in Tesla Model X SUV?
325 mi * 300 Wh/mi = 97,500 Wh or roughly 97.5 KWh battery
For daily drivers, this battery capacity value is really meaningless and this is probably why Tesla stopped advertising it but knowing your nominal battery consumption rate is very helpful.
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