Disappointing Range in P3D. Is this normal?

[bwilson4web]

If you try again...I would do a 10-20 mile warmup before starting (you could record those results of course), and I would wait for completely calm winds if possible. In Tulsa that could be a tough ask.

I prefer doing my tests after midnight when there traffic is light and often, no surface wind.

Bob Wilson

 

[ztuner]

i did a test...
All tests were 2 miles in length
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

my real life driving and range is around 277wpm with ac in and around town.

 

[MasterC17]

I am all for the tape method. Will have to do that for next road trip. Maybe remove the mirrors too

 

[Petra]

Just to add a few simulated numbers to this conversation, let's consider a 4 mph wind. If we stood outside in this wind, we don't perceive it as significant. Most people would probably call it "calm". I'd probably call it "light and variable". It's hard to tell what direction it's coming from sometimes. A wet finger held up tells us nothing and blades of grass dropped from shoulder height basically fall at our feet.

Now let's look at 3P-20" energy consumption at highway speeds. With no wind, just increasing the speed from 75 to 79 mph increases consumption by 6.6%. Decreasing speed from 75 to 71 mph decreases consumption by 6.2%.

Now let's have this car stay at 75 mph but add a 4 mph straight-on headwind. Energy consumption increases by 10.7%. With a 4 mph tailwind, consumption decreases by 9.6%. I was surprised at this. That's a large effect! I rechecked my old spreadsheet, as one does, and it all seems to check out. Fundamentally, what happens is that the car spends more time with the higher aero drag than it would if just traveling at the higher speeds. Energy consumption is energy used over distance (Wh/mi). In this example, the car spends 5.3% longer traveling at 75 mph vs 79 mph to go the same distance.

So with a barely perceivable wind, Wh/mi measurements at highway speeds can vary by +/-10% due to that wind alone.

What about a 4 mph direct crosswind at 75 mph? That's 75.11 mph at a 3 deg crab angle. The 0.11 mph faster airspeed increases the energy consumption by 0.3%. I don't know how quickly the Model 3 CdA rises with crab angle, while it certainly does, the difference is likely small at 3 deg. So a 4 mph crosswind may increase the Wh/mi measurement by 0.5-1.0%.

For those curious, a 10 mph headwind while driving at 75mph increases energy consumption by about 29% and a 10 mph tailwind decreases it by 22%. If you do a round-trip test by driving into a 10 mph headwind, then return with the tailwind, just averaging those results introduces a 3.5% error [(1.29+0.78)/2].

And this is why I've given up on attempting to test the efficiency impact of the aero covers... there are some good sections of road out here to test on, but the wind variability makes good data across consecutive runs elusive. I've thought about running two cars simultaneously, which does introduce other variables but also puts them on the road in the same conditions.

Paging @Petra

Around 250Wh/mile sounds about right for 75mph in my P3D- (or Stealth or whatever we're calling it now) with aero covers on. I'd need a calm day to do a test run on an empty stretch of highway to get constant speed efficiency numbers. I may get a calm-ish day (for the desert) within the next couple weeks, but it still won't be comparable to data collected by others.

There was that efficiency roundup that I participated in with Bjorn, but that also had its issues (people getting lost, groups getting broken up, etc.).

 

[ppower]

I am all for the tape method. Will have to do that for next road trip. Maybe remove the mirrors too

I've wondered what difference smaller profile mirrors would make. Since there are no cameras or such inside them, it shouldn't be too big of a deal for somebody to make low profile mirrors like 80's DTM style mirrors. The 3's rear visibility is bad enough that I'd stick with the bigger mirrors though.

 

[ryanmangos]

2 months in, not getting as much as I expected either. I would like more range but I understand I sacrifice range for fun. Haven’t taken it on a long drive yet. The most I’ve done is 70 one way trip. I commute from Monrovia to Glendale so this is with that horrendous 210 Pasadena traffic.

 

[MasterC17]

I've wondered what difference smaller profile mirrors would make. Since there are no cameras or such inside them, it shouldn't be too big of a deal for somebody to make low profile mirrors like 80's DTM style mirrors. The 3's rear visibility is bad enough that I'd stick with the bigger mirrors though.

Surprisingly, the mirrors don't make much of a difference. I think the ultimate solution is cameras in place of mirrors.

Independent Aerodynamic Study of Tesla Model 3 by Unplugged Performance

 

[jjrandorin]

I have 8k Miles on my Model 3 P now, and Most of my driving is commuting to and fro work which is 34-38 miles each way depending on which way I go.

When I first got the car in december of 2018 (12/04), my usage was over 300kWh for my regular commute. Yesterday, June 6th, I did that same exact commute with a usage of 211 kWh. Part of it is the "novelty" is worn off a bit as far as accelerating from a stop. I dont start off the line nearly as fast as I used to (but I do NOT use chill mode). I also dont baby it, I just dont look for that dopamine hit of acceleration at every stop.

The weather has warmed up as well. It does not get as cold as it gets in other parts of the country here, but morning commute weather has gone from high low 40s to mid 60s.

Parts of this drive are on the freeway at 80 miles an hour as well, so I am not driving at 65. I think my lifetime kWh is now in the low 260s, where it was over 300 from december - february.

 

[67King]

Surprisingly, the mirrors don't make much of a difference. I think the ultimate solution is cameras in place of mirrors.

Sadly, US laws often lag. Audi's etron has to add them for the US, but are replaced by cameras in the rest of world. Was the same way with sealed headlamps until I think 1986.

 

[Triplett]

My Benz got me 265 miles after 90 bucks in gas.

I'm not complaining about the P3D range.

 

[bwilson4web]

Sadly, US laws often lag. Audi's etron has to add them for the US, but are replaced by cameras in the rest of world. Was the same way with sealed headlamps until I think 1986.

Now if we could just 'fold them' at will on the road . . .

Bob Wilson

 

[wallet.dat]

Now if we could just 'fold them' at will on the road . . .

Yeah but knowing when is the tricky part.

 

[AlanSubie4Life]

I have 8k Miles on my Model 3 P now...

When I first got the car in december of 2018 (12/04), my usage was over 300kWh for my regular commute. Yesterday, June 6th, I did that same exact commute with a usage of 211 kWh.

....

Parts of this drive are on the freeway at 80 miles an hour as well, so I am not driving at 65. I think my lifetime kWh is now in the low 260s, where it was over 300 from december - february.

This is really good. I assume it is not a round trip number! I recall you are in Temecula, so that could be significantly downhill, depending on where you are going. If you can, report your return trip efficiency as well for the same endpoints! Would give a better idea of the overall achievable result.

I can easily understand this number for ~800 feet descent with significant traffic with only rare excursions to an actual 80mph. But I would expect the return trip to be closer to 300Wh/mi with the same traffic conditions and approximately same speed profile.

 

[jjrandorin]

This is really good. I assume it is not a round trip number! I recall you are in Temecula, so that could be significantly downhill, depending on where you are going. If you can, report your return trip efficiency as well for the same endpoints! Would give a better idea of the overall achievable result.

I can easily understand this number for ~800 feet descent with significant traffic with only rare excursions to an actual 80mph. But I would expect the return trip to be closer to 300Wh/mi with the same traffic conditions and approximately same speed profile.

You are correct, it was from temecula to work, but there was zero traffic and i was driving 80 ish MPH from onramp at winchester to off ramp at the 76, and then the 76 into Oceanside. You are also correct that the drive home has higher usage, but round trip is in the 260s now.

 

[AlanSubie4Life]

You are correct, it was from temecula to work, but there was zero traffic and i was driving 80 ish MPH from onramp at winchester to off ramp at the 76, and then the 76 into Oceanside. You are also correct that the drive home has higher usage, but round trip is in the 260s now.

I would be really impressed with a number close to 260 at those speeds! Maybe upper 260s, I would be a little less impressed.

I can't do better than about 280Wh/mi for a flat trip averaging 67mph with peak (the majority of the freeway travel) speeds between 75-80mph, and that's with traffic breaking a path through the air for me. (255mi range)


I should add that I am at 265Wh/mi avg for the last 700 miles, but I have a pretty optimal commute other than mandatory regen. Mostly 35-45 on Mira Mesa Blvd. Basically I don’t think anyone could much better than that for that specific commute. In general it is possible to do a little better of course.

 

[jjrandorin]

I would be really impressed with a number close to 260 at those speeds! Maybe upper 260s, I would be a little less impressed.

I can't do better than about 280Wh/mi for a flat trip averaging 67mph with peak (the majority of the freeway travel) speeds between 75-80mph, and that's with traffic breaking a path through the air for me. (255mi range)


I should add that I am at 265Wh/mi avg for the last 700 miles, but I have a pretty optimal commute other than mandatory regen. Mostly 35-45 on Mira Mesa Blvd. Basically I don’t think anyone could much better than that for that specific commute. In general it is possible to do a little better of course.

I usually take a different path home than going to work because of traffic (for locals or people familiar with the area I usually go home (oceanside to temecula) Local streets -- 76-- Pass 15 and continue on 76 past pala casino-- Through mountain to past pechanga casino.

There is a decent climb in there, so normally the return trip is around 280s or 290s. Was really surprised to see the trip to work that low this morning, particularly at the speed I was driving... However as you mentioned there are a couple of decent downhill spots on the path, and I have gotten progressively better at managing regen while driving. The hill specifically approaching 76 I can drive at 80 and pretty much have no line at all (no regen, no usage), traffic allowing of course, going about 80.

 

[AlanSubie4Life]

Makes sense.

I got my spoiler recently though so that adds 10HP and improves efficiency by 10Wh/mi!

I expect to see some serious gains on my benchmark routes.

 

[jjrandorin]

Makes sense.

I got my spoiler recently though so that adds 10HP and improves efficiency by 10Wh/mi!

I expect to see some serious gains on my benchmark routes.

I know your joking but I got my spoiler recently too (queue spooky music)

 

[Jedi2155]

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+.

 

[bwilson4web]

i did a test...
All tests were 2 miles in length
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
. . .

Per 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