For the last few months, my battery mileage indicator has been overstating mileage by about 20-25%. So, it also drains faster than you’d expect. I have a 90D and my max capacity shows as around 350 miles instead of 290 and it drains 50 miles on average when I’ve only actually driven 40. I thought this was a software problem but it has persisted even after recent updates. I talked to an owner of a Model X who has had the same problem. Anyone else aware of this and if there is a fix?
Battery Indicator Overstating Mileage
- Thread starter Benwald
- Start date
Hank42
Member
As a 5 year owner of Model S, I've learned a lot about the battery indicator over the years. For one, it is not exactly linear. And there are a number of factors that contribute to the actual reading. At the risk of repeating what's been said on the forum before here are just a few of the top factors to consider:
Temperature - both the average outside air temperature, and the actual temperature of the cells have a huge impact on range indication - I've noticed that on very cold day, my range might be 200 miles and 10 miles down the road, my range is 199 miles - even though I've driven 10 miles, only 1 mile was "consumed" - I liken that to the range indicator taking into account the temperature as the cells warm up to optimal temperature.
Driving habits/where you drive - My normal commute is generally flat, but sometimes I have to commute over a terrain that is very hilly. Regen is great and all, but coming down the other side of the hill does not get me back all the juice I used going up to front of it, and hence, the readout is affected.
Traffic/speed - Rush hour traffic jams are GREAT for range, they keep me under 55, and my range indicator is pretty accurate. It's those days that there is NO traffic and I take it to the limits in repeated acceleration/short stops that do me in. - I like to put my trip meter up on the dash screen and watch my "energy used since last charge" indicator- it does a good job of telling you if you are above or below the "rated" watt hours per mile.
All in all, my pack range has decreased less than 5% over the past 5 years - I'd say that's a pretty good number! But "your mileage may vary" as they say
I use rated range because it's very conservative. In practice, I get ticked off when I get less than Ideal range. But there's absolutely no one rating system that will cover every person's use. It's silly to think that there is, or is going to be**. As has been said many times, driving style, wind, weather, and terrain create a very wide variation in the range.
The closest Tesla has come is the trip graph which is very useful when driving in less than ideal conditions because it shows the variance between the estimate and what is being achieved.
** When real self-driving cars get finished and implemented, the human factor is removed so all that will be needed are wind and weather sensors, alignment sensors, tire pressure sensors hooked into the system, road surface data sensors, access to weather data, and detailed road surface data for forecasting the upcoming miles (the road surface data doesn't exist anywhere that I'm aware of), and a lot more computing power and storage to put it all together. Then the estimate can come much closer to reality. And of course, there will be an increase in price for all this--particularly for creating the database for detailed road surface data.
The closest Tesla has come is the trip graph which is very useful when driving in less than ideal conditions because it shows the variance between the estimate and what is being achieved.
** When real self-driving cars get finished and implemented, the human factor is removed so all that will be needed are wind and weather sensors, alignment sensors, tire pressure sensors hooked into the system, road surface data sensors, access to weather data, and detailed road surface data for forecasting the upcoming miles (the road surface data doesn't exist anywhere that I'm aware of), and a lot more computing power and storage to put it all together. Then the estimate can come much closer to reality. And of course, there will be an increase in price for all this--particularly for creating the database for detailed road surface data.
We've found our S 100D runs much closer to the rated range than our S P85 (VIN 3xxx).
The average energy consumption in the 100D is 305 Wh/mile - and on road trips, the Trip Planner is typically only a little optimistic on the amount of charge we'll have at the destination.
However, with our P85, energy consumption was much higher - and on road trips we'd see a significant difference between actual range and the predicted rated range. And the Trip Planner was always way too optimistic on charge, resulting in typical warnings between charging stops to slow down to extend range. With our P85 we would use the 20-20 rule when planning trips - take the distance to the next charger, add 20% and then add 20 miles - and this would usually work pretty well. And when we had high winds or elevation changes, we'd shift to a 30-30 rule to provide us more cushion.
With out 100D, actual usage is much closer to the Trip Planner prediction and rated range, though we still monitor consumption, especially if there are high winds or we do extended driving at 80MPH or higher.
The average energy consumption in the 100D is 305 Wh/mile - and on road trips, the Trip Planner is typically only a little optimistic on the amount of charge we'll have at the destination.
However, with our P85, energy consumption was much higher - and on road trips we'd see a significant difference between actual range and the predicted rated range. And the Trip Planner was always way too optimistic on charge, resulting in typical warnings between charging stops to slow down to extend range. With our P85 we would use the 20-20 rule when planning trips - take the distance to the next charger, add 20% and then add 20 miles - and this would usually work pretty well. And when we had high winds or elevation changes, we'd shift to a 30-30 rule to provide us more cushion.
With out 100D, actual usage is much closer to the Trip Planner prediction and rated range, though we still monitor consumption, especially if there are high winds or we do extended driving at 80MPH or higher.
Yeah, you definitely have it set on "ideal" miles instead of "rated" miles. None of the Tesla models have 350 rated miles on a full charge. Go into the settings screen and change it to rated, and it will be much closer to your real usage. Ideal is a very pie-in-the-sky overly optimistic type of mileage estimate that almost no one can achieve. Rated is pretty close, but just like with gas car EPA mileage estimates, most people don't drive quite that efficiently, so it's usually just a little bit high as well.
Some Tesla owners recommend changing the display units to "Energy" instead of "Distance", so that it will just show a % for the battery meter, so that it's not in your face that it's a little off, and you won't worry about it. That's a decent thought, but I don't think that way, because the places I drive are not measured in percentages; you always think about them in miles. I don't worry about it; I'm just aware that the rated miles are in the ballpark of being a little high, so if it says 200, that's maybe around 180ish real.
Oh, and if you're accumulating these measurements over several short trips, the numbers are going to be terribly off. When the car has sat for hours with the battery getting cold, the first few minutes/miles of use is going to show insanely high energy usage as it warms up the battery pack, which will level out for longer distances. I have about a 2 mile drive to work. In the winter, that 4 mile round trip sometimes uses up 8-10 rated miles. That's just the way it is for a short trip in the cold with running a lot of heat.
Thank you for the reply!! This is absolutely the problem. I must have been playing around with settings and changed this. When I set to ‘Rated’ the mileage shows much closer to the actual expected. Tesla should disable the ‘Ideal’ setting since it is clearly inaccurate and really not useful, far too over optimistic, for me more than 30% too high.
David29
Supporting Member
I use the energy setting for the battery indicator, not miles, because of what I have read over the years from more seasoned Tesla owners, and from my own 2+ years of experience. The battery indicator is only that, an indicator of state of charge. The display of miles is simply SOC in % times the EPA rated range (or the ideal range if that option is selected in Settings). It is not in any sense a predictor of the expected range you have available today with your driving style. It is accurate only if you drive in such a way that your car uses energy at exactly the rate implied by the EPA rating. But that is rare for anyone to achieve over a prolonged period, because of variations in ambient conditions, speeds, etc. Plus, from everything I have read, the battery management system is really not able to accurately calculate the SOC, especially at or near 100% charge. So, relying on the battery indicator as an indicator of range is misleading at best. At least, that is how I have distilled the hundreds of discussions of this topic that I have read over the past 3 years.
For the estimated range, the consensus seems to be to use the Energy application. Set it to calculate your average energy use for the recent driving that best suits what you are doing now (i.e. pick the setting of 5, 15, or 30 miles that best approximates what you think you will do on the next leg of your trip). And use the Navigation system when you are on a long trip so that the Energy app will build the graph of predicted energy use. It is not perfect (it accounts for elevation but not speed or temperature), but you can use it to monitor your current and predicted SOC and know if you will get where you are going without needing to charge more than you expected.
The other thing I do is to use the Trips data to develop a working feel for my energy use under various conditions. That way, I can compare my recent energy use with my long-term average and mentally account for the difference. For example, I know that my car's long-term average energy use is about 10% more than the EPA rated use (292 Wh/mi for my 70D). And I know that I can achieve the EPA average, or less, in nice weather in spring and fall when there is little need for either heat or AC, at moderate speeds. And I know that running errands on a cold winter day in New England will easily consumer energy at a rate of double the EPA rating or more (400-500 Wh/mi is not uncommon to see on such occasions). The battery indicator would be useless as a range indicator under such conditions.
Don't mean to lecture, but I hope that is helpful.
For the estimated range, the consensus seems to be to use the Energy application. Set it to calculate your average energy use for the recent driving that best suits what you are doing now (i.e. pick the setting of 5, 15, or 30 miles that best approximates what you think you will do on the next leg of your trip). And use the Navigation system when you are on a long trip so that the Energy app will build the graph of predicted energy use. It is not perfect (it accounts for elevation but not speed or temperature), but you can use it to monitor your current and predicted SOC and know if you will get where you are going without needing to charge more than you expected.
The other thing I do is to use the Trips data to develop a working feel for my energy use under various conditions. That way, I can compare my recent energy use with my long-term average and mentally account for the difference. For example, I know that my car's long-term average energy use is about 10% more than the EPA rated use (292 Wh/mi for my 70D). And I know that I can achieve the EPA average, or less, in nice weather in spring and fall when there is little need for either heat or AC, at moderate speeds. And I know that running errands on a cold winter day in New England will easily consumer energy at a rate of double the EPA rating or more (400-500 Wh/mi is not uncommon to see on such occasions). The battery indicator would be useless as a range indicator under such conditions.
Don't mean to lecture, but I hope that is helpful.
No, that's about right. In addition, Tesla messes with the rated range every so often, so it's not a really good indicator of anything, except that, for me, I find it conservative so I could use it as a guide (and I used to before the trip graph came out, which is much more practical because it compares the estimate to what was actually accomplished). The ideal range appears to be fiddled with less, probably because few people use it, so it's a better indicator of long term battery capacity. Even so, both are little more than SWAGs (scientific wild guesses) based on calculations more than actual measurements.
David29
Supporting Member
Here is an example of why battery SOC is not a reliable indicator of actual range.
This afternoon I went to a hockey game at a rink about 17 miles away. The route is part highway (60-75 mph) and part local roads (30-40 mph). The elevation at the hockey rink is somewhat higher than at my house. Ambient temps were in the mid-40s (F).
Before I left, the battery SOC was 69%, Using the EPA rating for the 70D, that implies a remaining range of 166 miles.
On the outbound trip, I traveled 17.2 miles, used 6.4 kWh, averaging 371.5 Wh/mi. That is using energy 27% faster than implied by the EPA rating. So if that rate of energy use applied for the remainder of a long trip, the implied range (for 69% SOC) would be only 130 miles, a big difference from the 166 miles implied by using the rated range.
On the return trip, the energy use was much lower. I used 5.3 kWh for 18.1 miles, or 292 Wh/mi, exactly matching the EPA rating. The lower energy use is probably due mainly to the drop in elevation.
For the overall round trip, the average energy use was 330 Wh/mile.
So the expected range depends a lot on how fast you are using energy, and even over this medium-length trip, the rate can vary considerably.
At the end of the trip, I looked at the energy app to see what difference the settings would make:
5 mile average, 133 miles remaining range
15 mile avg., 124 mile remaining range
30 mile average, 115 mile range.
So, choose the basis for your estimate wisely!
This afternoon I went to a hockey game at a rink about 17 miles away. The route is part highway (60-75 mph) and part local roads (30-40 mph). The elevation at the hockey rink is somewhat higher than at my house. Ambient temps were in the mid-40s (F).
Before I left, the battery SOC was 69%, Using the EPA rating for the 70D, that implies a remaining range of 166 miles.
On the outbound trip, I traveled 17.2 miles, used 6.4 kWh, averaging 371.5 Wh/mi. That is using energy 27% faster than implied by the EPA rating. So if that rate of energy use applied for the remainder of a long trip, the implied range (for 69% SOC) would be only 130 miles, a big difference from the 166 miles implied by using the rated range.
On the return trip, the energy use was much lower. I used 5.3 kWh for 18.1 miles, or 292 Wh/mi, exactly matching the EPA rating. The lower energy use is probably due mainly to the drop in elevation.
For the overall round trip, the average energy use was 330 Wh/mile.
So the expected range depends a lot on how fast you are using energy, and even over this medium-length trip, the rate can vary considerably.
At the end of the trip, I looked at the energy app to see what difference the settings would make:
5 mile average, 133 miles remaining range
15 mile avg., 124 mile remaining range
30 mile average, 115 mile range.
So, choose the basis for your estimate wisely!
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