Range University - Understanding why range is less than you expect

Range University - Understanding why range is less than you expect

Seems some owners are confused or worried the indicated range is inaccurate or lower than expected. We'll go into depth about how range is calculated and understand expected inaccuracies. We'll also explain battery degradation and types of rare battery failures. All you need to know about range!

akgolf | 08. Februar 2020


I’ve saved this for when I get my Cybertruck!

stingray.don | 08. Februar 2020

Great article! Well done!

andy | 08. Februar 2020


Tesla-David | 09. Februar 2020

Thanks @Teslatap, very well done and informative.

jimglas | 09. Februar 2020

That’s true for all cars except “Taycan”. For Taycan, add 50% to the range.

FISHEV | 09. Februar 2020

You should clean up some obvious misstatement of facts, your lead off for instance is wrong.

"Inaccurate Range Displays In an ICE car, the gas gauge is quite inaccurate"

They are very accurate providing tank level and range based on tank level. This can be user modified. An ICE person looking at this and seeing misstatement like that in lead off is likely to be skeptical of other claims.

And then there's this.

"With EVs and Tesla, in particular, a range display shows the distance left available to travel."

The Rated Range on Tesla is wildly inaccurate, 10-50% off, much more than range indicator on ICE vehicles while Projected Range on the Tesla is the most accurate range estimate. The buyer would not find that out until after purchase.

Probably best to lead off with the "bad news".

Your rated range in EV found on your car's sticker has to be significantly derated.

1. It is recommended that you only charge to 85% and not discharge below 10% so effective range is 75% of rated range on an EV, something you don't see on the gas tank on an ICE car. Look at 75% of Rated Range as the car's daily usable range. 100% of range is available for trips and special circumstance.

2. EV's lose 10%-30% or range in the colder weather and this deration starts at 50F.

3. Li-on batteries begin to lose range from day of mfg. 10% degradation in first year while not common, 3-5% range lose in first year is common) it is "within normal" limits. If your battery and/or driving results in a higher level of range loss can you live with it?

So look at Rated Range on sticker as being 75% to 50% fo usable range for every day driving.

Then show your calc sheet. Maybe add lines for "Average Winter Temp" 70F, 50F, 40F and 30F with 10F, 20F, 30F and 50% derations for temps.

You tell them what they need to know the most first and then they can use the rest of the info with that perspective in mind. But get rid of the misstatements on the ICE cars as most will see that and dismiss the rest out of hand.

jimglas | 09. Februar 2020

Fish is always wrong | 09. Februar 2020

@jimglas - Yep, usual grab bag of alternative "facts". Don't understand what he hopes to accomplish other than collecting his daily FUD fee.

jimglas | 09. Februar 2020

It’s not worth engaging with him and darth
They just ignore whatever facts are posted and repost their disinformation

msattler | 10. Februar 2020

On my model X energy graph it shows average consumption. What energy usage does Tesla use to estimate the range? If it is 300 miles per KH, then if I am using 330, does this mean I should expect 10% less range? Just observing, my 100% range seems to be 320 miles, but I would need to keep consumption under 300 KH to achieve this. | 10. Februar 2020

@msattler - Yes, that's a fairly good way to look at it. Of course, over a 1-2 hour ride, your energy usage will vary quite a bit depending on weather, hills, and winds.

mbirnie51 | 10. Februar 2020

@ msattler

MX 75D with 43,000 miles on brand new 20 inch Contis, with about 700 pounds of people, dogs and cargo

When I take extended trips, I keep a spreadsheet of data point I compile while Super Charging. On a recent trip (1700++ miles) I have a data point I call RANGE RATIO (RR) which is calculated by the number of miles of traveled (MT) by the miles of range used (MOR). My first leg I used 129 miles of range and I traveled 97 actual miles (97/129) yielding a RR of 0.75, and I averaged 353 wh/mile. This was generally flat terrain, 58 degrees F, cruise control set at 65 MPH for first 40 miles and then Navigate on Autopilot at 75 MPH for rest of this leg of the trip.

Another leg of the trip, the RR was 1.0 with 138 MT over 138 MOR. This leg was Grants Pass OR to Springfield OR (northbound) which is a drop in elevation for the first 75 miles and generally flat the last part. It was 38 degrees F at the start and 64 degrees F at Springfield. I traveled at 65 MPH on the downhill winding road until the flatter part, and kicked it up to 70 MPH for the lat 60+ miles Conversely, upon the return trip, the same Springfield to Grants Pass leg going south, the RR was 138/186 yielding 0.74 and a consumption of 380 wh/m. I cruised at 70 MPH until the hills, then dropped to 50-55 MPH up the hills (night time and foggy); and 35 degree F. Please note that my speed was dramatically reduced going south, if I replicated my northbound speed the wh/m would have gone above 420.

What I can determine from my experience is the sweet spot, or one mile of range equals one mile of travel is about 295 wh/m for a MX 75D. Ideal conditions would need to exist for this wh/m to happen, 60 degrees, little wind, generally flat terrain, speed kept to about 65 MPH (slowing to 50MPH up steep hills helps very much) @TT data sheet bears this out.

Techy James | 10. Februar 2020

TeslaTap my only suggestion would be of the comparison of the traditional Gas care gauge showing percent full versus the Tesla showing Miles. If the display setting is set to show percentage versus mileage than the two caparisons are direct comparison, and both are fairly accurate of Fuel/Energy left. Most current cars have anti-slosh features that reduce the effect of movement on gas gauge. The other issue would be related to fact you state that low roll resistance tires have 0 effect on range on ICE cars. It has a similar effect on both ICE and EV cars.
For the inaccurate comparison you would be the Miles till empty app many vehicles have. This is in both cases a fancy calculation based on the previous consumption over a range of miles. In the Tesla you change change this to be based on current or average over up to 30 miles.
The misconception from Tesla is when you're showing the Capacity in Miles over Percentage. That display is based not on recent usage but based on Rated range capacity. This range is based on what the car would be expected to use with Minimum Cabin energy usage, a speed of 65 MPH, with surface terrain of no elevation change, 0 Wind speed, and fair weather. This for example for my Model 3 LR RWD is 249 Watts per Mile. My average lifetime is actually 265 Watts per Mile. Slightly worst, but the tires I have that have a higher rolling resistance in exchange for better grip than what was stock for my car is likely to contribute to a higher rating.
Instead of using that rating I keep my car my car setting to show percentage. and if I want a little more accurate range I would got to the energy tab and look at projected range based on the last 30 miles. Now while I am driving I know that 10% equals for most driving conditions for my car about 26 miles this time of year, and in the summer that is closer to 33 miles. Now for users with extreme cold days (temps below 20F luckily not me any more) than the number would be closer to 23 miles per 10%.

FactDoc | 10. Februar 2020

Can you copy the text here?
The website is blocked from my work’s firewall and my phone died | 10. Februar 2020

@Techy - Good points, I've updated the gas gauge text. The chart does show low-rolling-resistance tires improves ICE range, but the asterisk text below the charge had an error, now fixed. Realize the chart is somewhat of a generalization, as I suspect a few ICE cars do come with low-rolling resistant tires. In such cases, there would be no improvement as they would have been used in the EPA efficiency ratings.

@Maxxer, there is a lot of text, formatting, a table, and graphics which would become a mess with the limited forum capabilities. Can you use a PC or tablet at home?

msattler | 10. Februar 2020

@mbirnie51, thanks that helps and confirms my suspicions.

@TeslaTap, good information.

NKYTA | 11. Februar 2020

Nice, @TT.