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Disappointing Range in P3D. Is this normal?
- Thread starter AtlasReardan
- Start date
Not sure what numbers you are using.
But 75,000 kWh battery / 264 wh/mi = 284 mi range. Not to bad, if it's a P3D+
To get 310 mi range you need around 241 Wh/mi (that is where the rated line is drawn on a RWD before 325 range update)
Using your harder math, (241 Wh/mi * 310 mi) / 264 Wh/mi = 284 miles
If you can get 230 wh/mi you will see your range estimate go well above 310.
I assume the updated software has the RWD rated line at around 230 wh/mi and that will give you 325 miles range.
AlanSubie4Life
Efficiency Obsessed Member
I realize all of this. I understand the AWD may technically only "expect" 295 (and I agree that is more realistic), but the EPA rated range is 310, so let's just keep it simple and go with that 310 number.
Maybe that is what the range estimate screen says - I haven't actually paid close attention to the range estimate value it displays for a given indicated Wh/mi. Might well be the case. But that range estimate is potentially different than the actual range you can achieve. (I'm curious on a trip whether that range estimate would align and be consistent with what the navigation thinks your arrival SoC would be - I've never checked).
I do not find this to be the case.
I used to use this math too, but I don't anymore.
Here is why, I have been paying very close attention, but you can do the same (for a reasonably long drive, 30-40 miles). This should be done in warm-ish conditions, not starting with a cold-soaked battery (maybe right after a prior drive), without really heating up the battery a bunch (because that can significantly change the rated miles displayed on the battery).
Note the following:
Trip meter miles traveled
Trip meter indicated Wh/mi (immediately after putting into park, but it must be in park to finalize)
The change in your rated range. (Take picture before and after, just before and just after taking out of park/putting into park).
Calculate:
(Trip meter miles traveled * Trip meter indicated Wh/mi)/(The change in your rated range)
You will find it comes out to around 230Wh/mi (at least that is what I get, consistently, for every reasonably long trip I take when the battery starts warm, and ends warm, for SoCs ranging from 100% to 25%). (Note this implies about 71.3kWh available in a full 310-0 discharge.)
I do encourage you to check it yourself, carefully. Ideally it is done for a > 100 mile trip so you have three significant figures, but 30-40 miles will usually be enough (you can have some error in the rated miles used if it is right about to switch over or just switched over, at the start/end of a trip - that is why it is the longer the better - those rounding errors become less significant). If it's not the same for you, it implies that the Wh/mi display accuracy is different for different users.
I did this several times, for several long segments, on my recent road trip, and I always ended up with 230Wh/rmi. EDIT: (Actually, it's closer to 232Wh/rmi, but tricky to say for sure to 3 significant figures...)
This indicates, irrespective of where any line may be drawn on any display, what Wh/mi you need to get on the trip meter, to get the rated range, for a full 310 miles to 0 miles discharge. Simply put, for me, I need to get 230Wh/mi to get the rated miles used to align perfectly with my distance traveled.
Do note this does not imply that the battery is not 75kWh or 77kWh of available energy. It may just imply that the trip meter Wh/mi reads low by a few %. (It could also imply there is some hidden energy below 0 - which we know there is - it's about 6 rated miles of hidden energy, which is nearly 1.5kWh.) The EPA doesn't care if that Wh/mi meter is accurate - they only care that the user has access (with a fully charged un-degraded battery) to the full energy that was available for the EPA test (which was measured to be 77kWh - 79kWh, in the EPA test documents - note this is when the wheels would no longer turn), and that the vehicle tested isn't a "special" super efficient vehicle - the efficiency of the test article needs to match (within manufacturing tolerance) that of the vehicles sold to the public.
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Well most of us know, the wh/mi meter on the main page cheats a little. It only tallies watts used while in Drive. The moment I touch the car the HVAC turns on and it stays on until the car locks itself. And when it does start up HVAC I think it's "boosted" at first.
The only time the wh/mi "extrapolation" is correct is if you actually drive from a full battery to an empty battery non stop. So yeah if you are extrapolating with chunks here and there, and even largish chunks. I can believe it would take 230 wh/mi to get 310 (because of some non driving waste) in practice. Based on what I've seend.
Anything I ever state is basically extrapolating the use of a full battery non stop, which nobody does in practice. But just using the wh/mi meter is for us to do relative comparisons. Everyone just uses the meter and theoretical capacity of the battery (which varies a bit on which size you choose to use). I just use 75 kWh which seems inline with the rated line Tesla draws on the chart energy.
The difference between what I say (240 wh/mi to get 310) and what you are saying in actual miles driven is only 4%. My guess is that is some waste that is not tracked by wh/mi meter.
There is also some phantom losses to contend with. So it depends over what period you measure as well.
To minimize some waste I keep my HVAC OFF when I can, and only turn it on when needed and shut it off immediately when I park.
No Sentry, No Cabin Cooling. My phantom drain has been great lately. couple miles a day.
Also I never like measuring "one way trips" (to many variables besides elevation). Unless maybe if it was a cross country trip. I only trust round trip measurements. And I typically never do a long round trip back to back. When I say long trip it would be something greater than 100 miles one way.
I think we mostly agree
If you want the real, real numbers, count the watts/hour your pumping in from your house and miles driven
AlanSubie4Life
Efficiency Obsessed Member
Yes. I have eliminated that source of error from all of my calculations of the 230Wh/mi. I was very careful about that. Was careful to only take pictures of rated miles right before putting in drive and right after putting in park (within a few seconds). I wasn't using HVAC with heat or AC for any of these calculations (because of the error that could introduce in the drain while in park).
That's true. It is possible that the bottom 25% of the battery it really slows down (but I have my doubts). For the numbers I have quoted, I have gathered data over a range from 310 miles to 78. (Sub-ranges within this range.) That's a pretty wide range, and I have to say, I did not detect any significant non-linearity of SoC indication over that range (100% to 25%). I was surprised at how consistent it seemed to be actually.
I measured/calculated trip segments from:
310rmi to 200rmi
305rmi to 262rmi
202rmi to 79rmi
Yes, it is 4%. But that would mean rather than 310mi, you would get 297mi, if you got 240Wh/mi. Assuming SoC estimate is linear. It's not nothing!
I think that some waste (or internal battery losses) not being tracked is likely. I think it is very likely the Wh/mi trip meter reads low for that reason. However, based on the EPA measured energy draw, the Wh/mi meter in the car is missing something that the EPA test DID capture (they used 4 different current-measuring clamps for the test).
https://iaspub.epa.gov/otaqpub/display_file.jsp?docid=46585&flag=1
Here are the stats from my most recent long trip segment. It was started with a warm battery (I had just stopped briefly to grab some food), and ended with the same warm battery. 70 degrees.
95.7mi @ 293Wh/mi. Rated miles started at 202mi. Rated miles ended at 79 miles. Time elapsed: 1 hour 29 minutes
This calculates to be 228Wh/rmi (but there is likely rounding error - the 202 clicked to 201 RIGHT as I started driving, and the 79 had just changed from 80 when I stopped). So it is more likely closer to 122 rated miles used, not 123. Which means it is closer to the 230Wh/rmi I stated.
But it's not just this one segment I've used - I calculated it for 3 different 30+ mile segments, and rechecked for my (short) commute this morning. It's always close to 230Wh/rmi if it's a long enough drive.
Mine seems pretty decent these days too. I haven't been tracking it closely but it could be as low as a couple miles a day. The only way for me to really check is to pay attention, and then not drive the car for 4-5 days.
My main point is that rather than looking at Wh/mi indicated, to determine whether you are going to get the rated range, just compare the miles you have driven (round trip, or at least for the same starting/ending elevation) to the rated miles used. You can't really conclude much from the indicated Wh/mi, except how you are doing relative to your prior drives. At least, not until you've calibrated how that indicated Wh/mi aligns to rated miles used. I am not even sure you can compare to other vehicles.
I think we mostly agree
Yes. I also 100% believe your numbers. I think your Pirelli P7+ tires are buying you about 30Wh/mi (indicated) relative to the PS4S. That's huge.
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-Wheels vs. tires. Above, it was just mentioned that there is little difference between the OEM 19's and 20's. Different tires. You say the P3D- can do 248Wh/mi at 77, so you think that the wheel/tire needs over 50% more energy? That makes no sense. I hope you're right.
-AP for efficiency or not? More people say to use it than to not. If I'm really trying to hypermile, sure, go manual so you can reduce speed going up hills and let it accelerate a bit going downhill. I've said before that an Eco AP mode would be great that would allow a fluctuation of maybe 5mph while going on grades. It is definitely not efficient if you slow down approaching any cars.
-Yes, the clearance is due to the slope of the barrel in the rear. Using a spacer gives more room because it pushes the narrower portion of the barrel outward. Gives more clearance further in on the barrel. The fronts do not need any spacers. They fit.
-I only have concern for range on road trips, so yes, aero covers for that. IDGAF what it is town where I can charge nightly. The only difference would be nice to feel like I could let it go days before recharging. Really, it's just about takin it out of town.
--PSI is 45 cold
-I do check/crosscheck the math various ways to look for ways something isn't adding up, but I'll keep in mind to add this.
-Will check for tire wear and see about another alignment to make sure the toe is correct. Excellent point that scrubbing would drastically affect efficiency. It tracks completely straight and true (better than any car I've ever had actually), but some toe could be adding stability while creating friction
-Yes, the Y will be less efficient, but the RWD will be the most efficient. I kinda have to wonder how much help lowering a 3 will do to assist its efficiency. Anyway, when we get that car, maybe I'll just put some sticky 9.5" wide wheels/275mm tires for the P. Not yet, though.
-AP for efficiency or not? More people say to use it than to not. If I'm really trying to hypermile, sure, go manual so you can reduce speed going up hills and let it accelerate a bit going downhill. I've said before that an Eco AP mode would be great that would allow a fluctuation of maybe 5mph while going on grades. It is definitely not efficient if you slow down approaching any cars.
-Yes, the clearance is due to the slope of the barrel in the rear. Using a spacer gives more room because it pushes the narrower portion of the barrel outward. Gives more clearance further in on the barrel. The fronts do not need any spacers. They fit.
-I only have concern for range on road trips, so yes, aero covers for that. IDGAF what it is town where I can charge nightly. The only difference would be nice to feel like I could let it go days before recharging. Really, it's just about takin it out of town.
--PSI is 45 cold
-I do check/crosscheck the math various ways to look for ways something isn't adding up, but I'll keep in mind to add this.
-Will check for tire wear and see about another alignment to make sure the toe is correct. Excellent point that scrubbing would drastically affect efficiency. It tracks completely straight and true (better than any car I've ever had actually), but some toe could be adding stability while creating friction
-Yes, the Y will be less efficient, but the RWD will be the most efficient. I kinda have to wonder how much help lowering a 3 will do to assist its efficiency. Anyway, when we get that car, maybe I'll just put some sticky 9.5" wide wheels/275mm tires for the P. Not yet, though.
BTW that is at 42 psi cold. If I was at 45 psi cold like some folks are running I think I'd gain another 20 wh/mi.
I'm concerned about to firm a ride at 45 lbs and uneven wear on a lower profile tire.
I suspect 45 lbs would not be a tread wear issue on 18". But could be on 19" and 20". Just guessing.
What does door tag recommend for 20" OEM wheels cold psi?
Door tag states 42 psi for both 18" and 19" (August 2018 and earlier door tag did state 45 lbs on Aero's).
I did try 45 lbs on the 18" and it felt like riding on basket balls. But wh/mi did improve quite a bit. I always ran 42 psi on 18"
AlanSubie4Life
Efficiency Obsessed Member
I doubt it would be that much. It’s a small effect for small changes. It’s 42PSI on the B-pillar as mentioned above. I based the change on Elon’s tweet. I think.
Feels like that on the 20” wheels anyway. But I am coming from a 2005 STi so everything feels very plush.
It was a huge effect on range adding 3 psi to 18", I don't recall exactly, but it was at least 20 wh/mi
This partly jives with what I found. But this was a model S. A more efficient Model 3 might see a larger difference per lb. One 10% for 10 psi (which is 23 wh/mi in my case). Another said 7% for 5 psi.
Range and tire pressure | Tesla
I used to run most ICE cars around 4 lbs above door sticker and easily got 2+ mpg more.
Elon has already applied this by running tires that typically would be run at around 36 lbs (for the weight/size car) at 42 lbs.
The Model 3 is sensitive rain, wind, elevation, 50 lbs of groceries. I'm sure 3 psi would be very significant.
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AlanSubie4Life
Efficiency Obsessed Member
I think it is more like 290-300Wh/mi for the P3D+ at 77mph (avg speed closer to 60-65 for the entire drive). That is just what I see - but admittedly I am comparing different cars so the Wh/mi indicated may not be equivalent. I will say my brother’s 248Wh/mi-indicated trip basically aligned on rated miles used: 248/230 * 195mi = 210rmi. So anyway it is an improvement from 290 to 250Wh/mi. Not 50%.
They will have the wrong offset from what I understand. They should be too far in by a few mm due to the thinner rotor hat.
AlanSubie4Life
Efficiency Obsessed Member
Maybe.
At least it is easy to find out! I would guess at most 10Wh/mi or about 5% for 42 to 45PSI, cold.
I don't think there is a lot of difference between the 19" and 20" factory setups as far as range. I do think the 18" Aeros make a huge difference. The 18" factory tires are designed for low rolling resistance where the tires on the 19" and 20" rims aren't.
The efficiency of tires are the biggest difference between OEM 18”, 19” and 20”. Not the rims. I think I found 19” rubber that is more efficient than the 18” OEM rubber. Because my 19” does as well as OEM 18” (with covers). Granted my 19” might not handle as well the any OEM tire. There are trade offs.
Everyone assumes the 18” OEM tire is the most efficient tire on the planet.
I never said the 18" OEM was the most efficient tire. I did say it is aimed at EV efficiency (low rolling resistance) where the OEM 19" and 20" aren't. I stand by that. It is a trade-off between handling and efficiency. Having cars with both, I think people are emotionally pulled to handling (I was) but in day-to-day use the extra range matters more. I haven't found the RWD on Aeros lacking in the handling area in normal driving.
Ok, not a full 310, but a representative 114 miles at an average 237 Wh/mi in 1hour 58 minutes using 27kWh of charge
Just under 60mph, but there is about 5miles of 25/35/45 mph, and significant section of the 5 has roadworks at 55mph.
Route was local->805->5->78->15->8->805->5->78->local
Air-Con and Music was on. Used a bit of AP to slurp a drink, but mostly manually drive. (on 2019.16.2)
Yes I do still have the 20s on with original performance tires, they are slightly under inflated at 40psi which gives a slightly more plush ride, and probably a little more traction.
My phone GPS tracker bombed out, and didn't save the route, or I would have posted the route/elevation/speed profile.
Was very windy, yesterday, and the route has alot of elevation change, you can look it up if you want. Didn't have time to extend to 310 miles, but still quite representative proportion.
Started at 90%charge (272 miles) traveled 114miles and ended at 156 miles. A discrepancy of 2 miles. However, my 90% charge bounces around from 270->279 miles. And 2 miles could be due to rounding.
So. by my reckoning, IF I charged to 100%, and averaged the same 237 Wh/mile, then I should be able to manage whatever the full charge indicates in terms of miles. Last time I charged to 100% it said 307 miles.
If I divide 75kWh by 27kWh = 2.777, and multiply by the miles 114, I get 316.666 miles
So, by the looks of it I am right in the ballpark of 310miles range
Just under 60mph, but there is about 5miles of 25/35/45 mph, and significant section of the 5 has roadworks at 55mph.
Route was local->805->5->78->15->8->805->5->78->local
Air-Con and Music was on. Used a bit of AP to slurp a drink, but mostly manually drive. (on 2019.16.2)
Yes I do still have the 20s on with original performance tires, they are slightly under inflated at 40psi which gives a slightly more plush ride, and probably a little more traction.
My phone GPS tracker bombed out, and didn't save the route, or I would have posted the route/elevation/speed profile.
Was very windy, yesterday, and the route has alot of elevation change, you can look it up if you want. Didn't have time to extend to 310 miles, but still quite representative proportion.
Started at 90%charge (272 miles) traveled 114miles and ended at 156 miles. A discrepancy of 2 miles. However, my 90% charge bounces around from 270->279 miles. And 2 miles could be due to rounding.
So. by my reckoning, IF I charged to 100%, and averaged the same 237 Wh/mile, then I should be able to manage whatever the full charge indicates in terms of miles. Last time I charged to 100% it said 307 miles.
If I divide 75kWh by 27kWh = 2.777, and multiply by the miles 114, I get 316.666 miles
So, by the looks of it I am right in the ballpark of 310miles range
AlanSubie4Life
Efficiency Obsessed Member
Thank you!
Impressive result, I have to say. Looks like it likely would be possible to beat my (modified) challenge of 290mi at an average speed of >60mph. This was an average of 58mph.
A few minor corrections:
You traveled 113.6 miles and used 116 rated miles.
You had indicated 237Wh/mi.
This, BTW, confirms my claim that 232Wh/rmi (well I said 230Wh/rmi but I was rounding - the longer distance calculations usually do come out closer to 232Wh/mi -splitting hairs really) is the correct constant:
113.6mi * (237Wh/mi) / (232Wh/rmi) = 116rmi
Note that this trip therefore extrapolates to:
Max range = 113.6mi * (310rmi/116rmi) = 303.5mi
So you are on pace for 303.5mi range with this drive. Not 316mi. That is for 310rmi to 0rmi discharge, and does assume no nonlinearity in the SoC indication.
(You should not assume 75kWh for a full discharge - the car is telling you there is not that much available (as far as the meter is concerned - it may actually be available but that few kWh of extra energy are not being counted by the trip meter).)
So, it would be really close at >60mph. But probably possible.
I guess I should try a lap!
What happened at the end? Is it all downhill at the end? This was zero net elevation gain, right? I assume you started uphill but it is no longer being displayed of course as a high consumption time...
As long as the net was zero elevation change and the freeway hills were not steep enough to push you into regen (at 60+ mph it would have to be pretty steep - the only ones that might are some of the hills on I-15), the undulations should have nearly zero effect.
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Yes, the maths aren't exact, but are is the right ball-park. Now, if this was a flat route, (there is about 2000+ft of undulation for each loop) then would be more efficient (Higher power to climb is less efficient). Yes, does some regen on the hills on the I15.
Starting elevation 423feet
Ending elevation 315feet
Lowest elevation about 10feet (bridge over inlet on the 5)
Highest elevation about 800feet on the 15.
Last couple of miles is about 200ft elevation drop on 25/35 mph rural road.
Before that, turning off the 5 at sea level to go inland/up on the 78 to 500ft
The photo shows the last 30miles, going north on the 5, then east on the 78 and the local road.
Higher energy used going east on 78 and south on the 15 which is undulating.
Lower energy used going north on the 5 close to the coast.
If I went north/south on the 5 rather than a loop going inland and though the mountains, I'd be closer to 210 Wh/m. Climbing the hills bumps it up to 300-400Wh/m range which you don't get back going down again.
AlanSubie4Life
Efficiency Obsessed Member
Yikes. That’ll take the extrapolated full range down to 301miles @ 58mph avg
Would be super close to making 290miles at >60mph avg I think. But would almost certainly make it, assuming no not-in-your-favor nonlinearity at the bottom of the battery. 65mph I think you almost certainly would not make 290miles.
I’ll do a lap when I get a chance and will post here.
