Disappointing Range in P3D. Is this normal?

[jjrandorin]

Most interestingly, I recently came back from a S 75 loaner (RWD), and I was getting averages of 260 Wh/mi compared to my 280 on my P3D+.

Since the model S is such a "boat" (at least compared to the model 3), even on the same roads I would imagine you were likely "driving it different".... but I am just guessing. Do you feel you drove both cars exactly the same?

When I have been in loaner model S from the service center, they feel every bit as heavy as they are to me.. unlike the model 3. Kind of the same reason my previous car was a BMW 4 series instead of a 5 series, even though I could have afforded both. The model S drives like a cross between a BMW 5 and 7 series to me. Very much "executive saloon" and not very much "sports sedan".

 

[Jaguar]

I took my P3D+ with the 20" performance wheels on a highway range test yesterday. It was calm and 75 degrees; the course was out and back and I used about half the battery during the trip. I wanted to see if 310 miles was possible and what speed it would take to do that, so I drove at 56 mph (that's the speed limit here -- 90 kph). I got 234 Wh/m which works out to 320 miles assuming a 75 Kwh battery. The other gauges -- energy used, range estimator -- all came to a similar figure, so I'm satisfied that, in summertime, at that speed, 310 miles or more is reasonable. I'll try it again at a more realistic 60 mph, but I'm predicting close to 300 miles. Overall, I'm very pleased with the performance.

 

[AlanSubie4Life]

I took my P3D+ with the 20" performance wheels on a highway range test yesterday. It was calm and 75 degrees; the course was out and back and I used about half the battery during the trip. I wanted to see if 310 miles was possible and what speed it would take to do that, so I drove at 56 mph (that's the speed limit here -- 90 kph). I got 234 Wh/m which works out to 320 miles assuming a 75 Kwh battery. The other gauges -- energy used, range estimator -- all came to a similar figure, so I'm satisfied that, in summertime, at that speed, 310 miles or more is reasonable. I'll try it again at a more realistic 60 mph, but I'm predicting close to 300 miles. Overall, I'm very pleased with the performance.

That’s an incredible result. This is a stock P3D+ with the original tires (PS4S)? (Also what was the overall average speed - max was 56mph?)

Motivates me to want to get out for an hour today and find a flat section and do some tests. I did get a chance on a perfectly flat section of freeway (if there was any negligible slope it would have been downhill, due to lay of the land, but checked the topo, and it is flat) to set the cruise to 75 and got 285Wh/mi with no drafting at all (which aligns well with my prior results).

Everyone doing this type of range testing should also watch their rated miles indicated during their test. I think you would find you are on target for closer to 305-311 miles.

(230/234)*310 = 305
(235/234)*310 = 311

I’ve found consistently that for every 230Wh used my rated range decreases by 1mi. The actual value may be as high as 235Wh, hence the range of values.

That’s just to rated miles of 0 of course - you have about 5 EPA miles after that.

And no, this does not imply a 71.3kWh battery (230Wh/rmi*310rmi = 71.3kWh). It’s just a meter, and can only be used to compare performance relative to other performances; it’s not “NIST-approved” (or bureau of weights and measures approved for that matter) for measuring energy use! (That’s also why it is good to calibrate your own trip meter consumption to rated miles - the trip meter may not measure exactly the same way for everyone...since it is just a measurement - I don’t know.)

 

[AlanSubie4Life]

25 mph no ac - 165wpm 454 miles range
35 mph no ac - 177wpm 423 miles range
45 mph no ac - 198wpm 378 miles range
55 mph no ac - 218wpm 344 miles range
65 mph no ac - 257wpm 291 miles range
65 mph with ac - 262wpm 286 miles range

I disagree with the extrapolated range here. I would use a worst case constant of 230Wh/rmi, or 235Wh/rmi if you want to be optimistic. This is for the AWD/P3D (it's probably different on the other vehicles).

So:
35mph => 403 mi
45mph => 360 mi
55mph => 327 mi
65mph => 277 mi

Excel trend line:

wpm = (0.0379 * mph**2) + (-1.1571 * mph) + 170.84

• 170.84 - rough estimate of watts when stationary
• -1.1571 w/mph - adjusts for poor aerodynamic fit at 1-4 mph, fixed overhead dominates
• CAUTION: trend line formula is only good in 25-65 mph range. Projected performance outside can be off

Bob Wilson

So I ran some quick tests myself. I think the impact of hills which are steep enough to require regen (part of my standard commute) is greater than I anticipated. Either that, or the spoiler is helping a LOT . I say this because I was really quite surprised at how good the results were, given my regular commute. Also no stopping/starting, so that of course helps. (Sadly, I ran no tests on this particular test course prior to the install...so I'll have to compare to my commute numbers, at some point.)

Test conditions:
Sort of flat course (80 feet over 2.5 miles, each direction; that's as flat as I can get for a variable speed course without annoying people). Round trip (composed of two constant speed segments in opposite directions, north and south). All data logging started when up to speed. AC & fan off. 84 degrees, west wind (cross wind) 9mph. Elevation: 400 feet. (Kearny Villa road east of Miramar.) There were just a couple other vehicles, so there was minimal/no drafting.

Vehicle:
Tire PSI: 45 (cold), 49 operating. P3D+, 5000 miles, Stock, WITH SPOILER

My data is similar to above data from @ztuner, except for the 45mph datapoint , which is MUCH different - which makes sense to me, it looked out of line compared to 35 and 55 mph - I was not able to gather 35mph. I would expect 45mph to be closer to 35mph than to 55mph, since that makes the aero loss scaling more sensible. The data above suggests a 43-mile range loss 35->45mph, but then 33-mile range loss when going from 45->55mph, which seems a little off to me, even with fixed losses scaling down.

Total of 4.8 miles "round trip" (two length equal segments at constant speed in opposite directions):

35mph: 177Wh/mi (403mi range) <= Not my data, placeholder from above, seems a little high.
45mph: 180Wh/mi (396mi range)
55mph: 214Wh/mi (333mi range)
65mph: 255Wh/mi (280mi range)

 

[AlanSubie4Life]

• 170.84 - rough estimate of watts when stationary

I don't think I agree with this assessment. This has units of Wh/mi, so it's not the watts when stationary. If this were actually a perfect formula & model (which it's not), this coefficient 170.84 would represent losses that require power proportional to speed to overcome, like rolling resistance. Wh/mi has units of force (1Wh/mi is 2.23Newtons) . So, this coefficient is just the constant force resisting the car's movement - like rolling resistance, some drivetrain losses, inverter losses that scale with linearly with power, etc.

What about watts when stationary?

Wh/mi (v) (Wh/mi as a function of speed, your fitted formula above) can be converted to W as a function of speed by multiplying by velocity.

So you'd take your fit above and multiply by mph:

W = 170.84*v - 1.1571*v^2 + 0.0379*v^3

The watts when stationary (for this formula) would be the Y-intercept...which is zero. (So, I think there should be a constant term added above - this would work out to be a term INVERSELY proportional to velocity in your original "Wh/mi" formula, to account for reduction in the contribution of fixed losses with velocity.)

Alternatively, you could fit watts (not Wh/mi) to a cubic function, but it still ends up being pretty sketchy at the ends (very non-physical Y-intercept unless you have a way of measuring the fixed losses directly and plug that in as your zero value (probably the best option from a physical modeling standpoint, but you have to make some assumptions about how these things work which may be invalid)). I would guess the best option is just to do a long 10mph datapoint if you want to get an estimate of the true fixed losses. But no idea really.

So anyway, as you said, of course you can't extrapolate outside a narrow range for your formula (for various reasons - this being one of them), but the y-intercept of zero also suggests something slightly wrong with the formula, from a physical model point of view! In the end it's not that much error, really, because even at 35mph the car is using something like 6kW. And likely the fixed losses are something like 300-400 watts (just a guess, no idea really).

 

[Jaguar]

That’s an incredible result. This is a stock P3D+ with the original tires (PS4S)? (Also what was the overall average speed - max was 56mph?)

Motivates me to want to get out for an hour today and find a flat section and do some tests. I did get a chance on a perfectly flat section of freeway (if there was any negligible slope it would have been downhill, due to lay of the land, but checked the topo, and it is flat) to set the cruise to 75 and got 285Wh/mi with no drafting at all (which aligns well with my prior results).

Everyone doing this type of range testing should also watch their rated miles indicated during their test. I think you would find you are on target for closer to 305-311 miles.

(230/234)*310 = 305
(235/234)*310 = 311

I’ve found consistently that for every 230Wh used my rated range decreases by 1mi. The actual value may be as high as 235Wh, hence the range of values.

That’s just to rated miles of 0 of course - you have about 5 EPA miles after that.

And no, this does not imply a 71.3kWh battery (230Wh/rmi*310rmi = 71.3kWh). It’s just a meter, and can only be used to compare performance relative to other performances; it’s not “NIST-approved” (or bureau of weights and measures approved for that matter) for measuring energy use! (That’s also why it is good to calibrate your own trip meter consumption to rated miles - the trip meter may not measure exactly the same way for everyone...since it is just a measurement - I don’t know.)

My car is completely stock with the original tires. I tried to make 56mph my average, which meant traveling at speeds that ranged from 53 to 63 depending on the terrain. I did not use cruise control because my course was a bit hilly and CC accelerates going up hills and often brakes going down, neither of which is good for range. So I would let the car gain speed up going down hills and rub off speed going up but I never went below 53 or above 63 mph and held it steady at 56 otherwise. I set the car at maximum regen. A few stops at intersections and waiting for lights to change brought down my range.

I made one mistake along the way. I was cruising nicely along a flat stretch with the 30-mile rating falling well below 190 Wh/m when I decided to explore a new road. Once I rounded another corner I encountered a steep, long hill dropping right down to the shore of Lake Superior. Descending was fine as the regen recouped lot of energy, but going back up negated all of that and a lot more.

Other factors I consider when doing range tests. Wind makes a big difference, which is why I use an out and back course. Hills, even mild ones, will result in a net loss. Also, I don't trust range estimates based on short trips. My car takes at least ten miles at the start just to make up for the energy it uses heating the battery to proper operating temperature. I never test without going at least 100 miles, usually more. This isn't a problem as driving the car is such a pleasure.

Oh, by the way, I ran the fans all the way but not the AC. It wasn't that hot.

 

[AlanSubie4Life]

My car is completely stock with the original tires. I tried to make 56mph my average, which meant traveling at speeds that ranged from 53 to 63 depending on the terrain. I did not use cruise control because my course was a bit hilly and CC accelerates going up hills and often brakes going down, neither of which is good for range. So I would let the car gain speed up going down hills and rub off speed going up but I never went below 53 or above 63 mph and held it steady at 56 otherwise. I set the car at maximum regen. A few stops at intersections and waiting for lights to change brought down my range.

I made one mistake along the way. I was cruising nicely along a flat stretch with the 30-mile rating falling well below 190 Wh/m when I decided to explore a new road. Once I rounded another corner I encountered a steep, long hill dropping right down to the shore of Lake Superior. Descending was fine as the regen recouped lot of energy, but going back up negated all of that and a lot more.

Other factors I consider when doing range tests. Wind makes a big difference, which is why I use an out and back course. Hills, even mild ones, will result in a net loss. Also, I don't trust range estimates based on short trips. My car takes at least ten miles at the start just to make up for the energy it uses heating the battery to proper operating temperature. I never test without going at least 100 miles, usually more. This isn't a problem as driving the car is such a pleasure.

Oh, by the way, I ran the fans all the way but not the AC. It wasn't that hot.

All seems reasonable. After my testing from yesterday this number seems reasonable; I got 214Wh/mi at 55mph.

Next time you do a nice long drive like this (assuming it is done in one shot), make a note of the rated miles used and compare to your Wh/mi...curious whether you end up with the same constant I do (I think you will be close as your results for indicated efficiency for a given speed seem close). I would expect 230-235Wh/rated mile.

 

[Jaguar]

All seems reasonable. After my testing from yesterday this number seems reasonable; I got 214Wh/mi at 55mph.

Next time you do a nice long drive like this (assuming it is done in one shot), make a note of the rated miles used and compare to your Wh/mi...curious whether you end up with the same constant I do (I think you will be close as your results for indicated efficiency for a given speed seem close). I would expect 230-235Wh/rated mile.

214Wh/mi equates to nearly 350 miles of total range! That's amazing. You must be driving on very flat roads. As I live on the shore of Lake Superior every trip I take starts off uphill.

My next test will be at 60mph and then I'll try 50mph -- lots of side roads here that will enable that speed without holding up traffic.Will take a closer look at rated miles used.

 

[AlanSubie4Life]

214Wh/mi equates to nearly 350 miles of total range! That's amazing. You must be driving on very flat roads.

See above for the details. It was a relatively short course so the numbers are subject to some error - especially if there are any things that occur periodically which use energy.

For my car, 214Wh/mi equates to:

(230Wh/rmi)/(214Wh/mi)*310rmi = 333 miles

It is possible it could be as much as 340 miles. (235Wh/rmi)

This is all assuming I don’t dip into my reserve of about 5 miles (or whatever) below 0 rated miles.

 

[AlanSubie4Life]

I tried to fit a physical model (rather than fitting to EPA coefficients).

Here's a fit of my 3 datapoints, plus two datapoints I made up for 25mph & 35mph (though they seem reasonable based on an aero model, in conjunction with reducing fixed losses between 25mph & 45mph).

Wolfram|Alpha: Making the world’s knowledge computable

This is a formula for Watts, NOT Wh/mi. But the y-axis data points are entered as Wh/mi * velocity. This gives you the actual watts for a given speed. So you can try to fit your own data if you want. Warning: small changes in the data can lead to very large changes in coefficients...

You can divide through by velocity to get the Wh/mi formula.

So it's watts = 0.035*v^3 + 101.5*v + 362 (dropped the minimal v^2 term, which I can't think of a physical reason for - it may well exist though)

Or Wh/mi = 0.035*v^2 + 101.5 + 362/v

Notably, 362 (units of watts) is the fixed loss when stationary. I basically picked this value to fit my three points...so don't read too much into it - though I think it's in the general ballpark.

101.5 (units of Wh/mi) are the fixed losses (rolling resistance, etc.). Again, don't read much into this. This is the one that is going to change quite a bit when you put on different tires.

Anyway, with some very careful data gathering of the 25mph & 35mph plots it might be possible to get a better model. I think the 0.035 coefficient is actually pretty reasonable, might be slightly high. This coefficient would change when you put aeros on. The other coefficients potentially could be quite off (fixed losses could be lower and rolling resistance higher, or vice versa), and are subject to errors in the datapoints used to fit the model.

To validate this model as being "good", I'd need to get 138Wh/mi at 25mph and 155Wh/mi at 35mph (I'm not sure how probable this really is). So please don't take anything here as "accurate." It's just playing around.

This formula also predicts 303Wh/mi at 75mph, which to me seems high. So the squared term coefficent may be SLIGHTLY high.

Also worth noting that the fit of this model is highly dependent on the input data. So if the meter in the car becomes less accurate at lower consumption (some have claimed this) it would make it very difficult to develop an accurate model, unless you know how that error behaves.

 

[ppower]

I posted the results of a test in a couple of groups but thought it could be beneficial to add here. Logic and articles say that there should have been no discernible improvement, so take this with a grain of salt for now. After seeing even more talk about panel gaps and my frunk gap being larger than I'd prefer, I wondered about the old wive's tale? about taping the seams of a car for high speed. Could I see any benefit at highway speed?

I took a 10 mile section, taken both ways to average out any wind and elevation. Driving in chill, AP at 65, reset the trip once cruising at 65 to avoid acceleration or regen. This is able to be done within an hour keeping weather conditions as close to the same as possible. The longer the distance, the longer the time and changes in conditions through the day could affect it more. This was the most efficient my car has EVER been with or without tape. This makes me wonder if there was something else in the new update.

Open gaps: 214 +308Wh/mi =261Wh/mi average

Taped gaps: 208 +292Wh/mi =250Wh/mi average

4.6% improvement. I imagine the higher the speed, the higher this percentage improvement might be. I don’t know that I want to put on painters tape for every road trip, but I’ll consider it.

Edit 1: 2nd test with botched results.

Open gap:
212 + 297 = 254.5Wh/mi average

Taped gap:
207 + 296 = 251.5Wh/mi average.

So the first trip showed similar efficiency (207 vs 212 and yesterday’s 208 vs 214). I kept driving at steady speed where the highway turned and went from headwind to crosswind and in 3.5 miles dropped the average by 12 Wh/mi. This doesn’t factor into tape vs no tape, but it’s amazing how wind affects the car. Anyway, got home and saw the tape all pulled up. I think it happened at the beginning of the headwind test run and completely negates the information. I'll have to do at least a 3rd try at this. Maybe I can get free and do another test today.

Side note: the big spike is me giving somebody a ride at the end of our Caffeine and Gasoline car meet. Kinda funny to have the big spike in the middle of testing efficiency.

Just quoting this to add that I've done more tests. Every time I'm getting the same 4% improvement. I did 30 mile stretches at 79mph and saw a 5% improvement. When the tape lifted across the front edge of the frunk, I then saw 5% WORSE efficiency. So as speed increases, the aero affect is magnified. It's worth seeing if anybody else sees any kind of result at all. I've done it about 5 times with consistent results. It's certainly enough that I'll look in to getting rubber seal for that gap.

 

[Triplett]

I'm getting far less range......and LOVING it.

 

[dfwatt]

I'm getting far less range......and LOVING it.

Yes every time I try to hypermile, the gas pedal just talks to me saying "please, please you must stomp the s*** out of me me." I resist mightily but the siren song eventually gets to me and I have to just smoke the launch from the last stop light. Unlike a comparable (if there are truly comparable) ICE sports sedans (AMG 6.3 BMW M3 Alfa Romeo Quadrifoglio) there is no freakin noise at all from launch. So you can use all that delicious torque without drawing any untoward attention to your stealth machine. Unfortunately all the neighborhood kids in our area know about the car just from the media attention it's getting so they're always coming by to Google it and ask for quick blast offs.

Like I said hypermiling doesn't have a chance!

 

[Triplett]

I don't know about the rest of you, but I'm happy about the 76 miles of range I get off a full charge...

 

[Triplett]

I just checked my P3D. 270 miles at 90%. That's just short of exactly 90% of 310 miles so I have no complaints.

 

[dfwatt]

I don't know about the rest of you, but I'm happy about the 76 miles of range I get off a full charge...

I assume you mean the 76 miles you get at the track? While people may think that's horrible it's still the equivalent of 35 plus miles per gallon at least in the mpge metric. Try to get that around the track in any internal combustion engine sedan.

 

[TwoK4drSi]

Can anyone here go more than 3 days without a charge? Every time I try in know my HP per SOC is low so I need to top off every other day LOL

 

[ppower]

I just checked my P3D. 270 miles at 90%. That's just short of exactly 90% of 310 miles so I have no complaints.

That’s not what we’re talking about. That is the equivalent of having an accurately full tank. That 270 miles is only 270 miles when your Wh/mi is 240 or less. For that reason, the 270 miles is virtually meaningless. Change it to % instead of miles.

 

[drtimhill]

Two weeks into ownership of my M3 LR AWD, and also experimenting with range under different conditions. Here in moderate temperature Seattle I’m seeing close to expected range. What I’ve found is to keep the trip card open on the screen (swipe left to right in the card space where the wiper icon is). This shows you the short-term Wh/mi value over the last few miles, which I found invaluable to figure out what driving patterns were good/bad for mileage.

One take-away for me is slow stop-start in traffic can be bad (600-800 Wh/mi), while driving along at moderate speeds (35pmh) was VERY efficient. Overall I’m getting 260 Wh/mi average without making any special effort really. Note that I do have the Aero wheels though.

—Tim

 

[Roy Wasson]

As far as dropping down into neutral to coast sometimes, in 8 years of driving Leaf EVs, I have developed the knack of being able to coast in neutral just the right distance so when I go into regenerative mode (called :B" gear on the Leaf), the deceleration from that takes me down to a full stop at just the right place. Trouble is that I have been driving the Model 3 for three months and cannot figure how to get the car into neutral at speed. Thanks in advance for the tip.

Roy