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175 miles for outward leg versus 36 miles for return leg

175 miles for outward leg versus 36 miles for return leg

I made a round trip from my home in Longmont, CO to the Loveland Ski Area and back. The distance is 92 miles each way. I left with 275 miles of range on the battery. When I arrived I had 100 miles of range. After skiing for 6 hours I came back to my car and it had 88 miles of range. When I returned home I had 52 miles of range. I'm surprised by these numbers and the very large discrepancy between power consumed on each leg of the trip (175 miles out and 36 miles back). Here are the factors I can identify which might have contributed to the discrepancy:

1) Elevation change. The elevation in Longmont is 5,000' and the elevation at the Loveland Ski Area is 10,800'.

2) Speed. On the outward leg I drove in the left lane at the same speed as the other traffic in that lane (using autopilot most of the time). On the return leg I drove manually the whole time in the right lane and kept the speed mostly between 45mph and 55mph. At times I had to go faster (up to 65mph) to avoid obstructing traffic.

3) Climate control. I ran the heater at 65 degrees Fahrenheit on the outward leg but I turned it off completely on the return leg due to range anxiety. The outside air temperature ranged from 5 degrees to 15 degrees. It was very uncomfortable with the heater off (cold hands and numb toes by the time I got back) and I had to run the front defroster (in cold mode) periodically to defog the windshield.

Have others had similar experiences? What factor do you think contributed most?

Mike UpNorth_ | January 4, 2019

I think you nailed the factors and in order of importance.

Mike UpNorth_ | January 4, 2019

But losing 12 miles of range as the car sat there for 6 hours seems abnormal to me. Unless you preheated the cabin a while before leaving.

draymond | January 4, 2019

I didn't preheat the cabin before the return leg. Maybe the 12 mile loss was due to the battery temperature dropping after parking the car?

jimglas | January 4, 2019

Similar experience driving to breck

mrburke | January 4, 2019

@michael - I have a theory on the "lost 12 miles". When Draymond stopped, the battery was warm, and the range was computed based on a warm battery. When he (or she) returned the battery was cold and the range was computed based on a cold battery. So the car did not actually loose 12 miles while parked.

Once again, it is just a theory.

Jiver | January 4, 2019

I have similar concerns about a weekend trip from Colorado Springs to Winter Park. I doubt that I would have enough energy to make it from Winter Park to the Park Meadows Supercharger on the return leg (LR AWD).

However, in your situation, why not just go the 8 miles down the hill to Silverthorne and hit the Supercharger for a bit? That would have killed the range anxiety and allowed you to be warm on the way home. If traffic was bad heading up to the tunnel I can understand why you did not do that. Sure, 16 miles out of the way but warm hands!

The solution for both of us is the Idaho Springs Supercharger. It is listed for 2019 but who knows if that will happen or not. Steamboat Springs Supercharger was listed as 2018 and now it has rolled to 2019 as well. For us on the front range those two supercharger will make a big difference in ski season.

lbowroom | January 4, 2019

To put it in the context of your ski trip. Imagine the energy you would use to hike up the mountain, and then the energy you would expend to ski down.

greg | January 4, 2019

Ok for starters, those figures (overall) seem about right for the type of trip you did.

You drove 184 miles (92 miles each way), while the car consumed (275-52) miles of range = 223 miles of battery range (calculated at the normal usage rate of 240 Wh/mile).

So the "penalty" you incurred if you look it like that was only the 39 miles you "lost" in range over an above the mileage you drove.

The reasons for the difference are due to a mixture of:

(a) vampire drain while parked/off skiing
(b) driving on winter roads (higher rolling resistance) and/or with winter tires
(c) colder than usual battery on both legs due to cold external temperature
(d) likely higher speeds on outward leg compared to return leg
(e) elevation change
(f) use of cabin heating on the outward leg
(g) not stated - but side/headwind losses (headwinds in particular can impact range).

Since it appears (vampire drain a) was 12 miles, thats fully 30% of your "unexpected" range loss right there.

Most likely this was due to the battery [and cabin?] keeping itself warm(er) than the outside temps while you were off skiing for 6 hours..

So the remaining 27 miles were lost for reasons (b) through (g).

I suspect cabin heating had a big effect on the outward leg, after all, you spent ~80 miles more than normal getting there. Cabin heat can suck the equivalent of 20 miles an hour of range (4.8 kWh which at expected consumption of 240 Wh/miles = up to 20 miles per hour of usage)

You trip included 5000 feet (at least) of uphill elevation changes and (I predict) higher speeds. Going uphill in any vehicle (EV or ICE) really hammers the fuel efficiency - but an EV unlike any ICE will get a fair chunk of it back on the downhill. So thats why your "outward" leg hammered your range so much - going up 5000 feet, turned a 92 miles trip into a much, much longer one. Coming home, the regen recouped most of that given the fact you appear to have got 60 odd miles of range "for free" given the range used on the return leg.

Elevation changes overall however may have played a similar sized part to cabin/battery heating.

While you should recoup most of the energy on the downhill, if the battery is cold or the road is slippery the regen will be more limited - so more of that elevation will be wasted by the car slowing using the vehicle brakes (resulting heating the brake pads and little else).

So all in all, I think you got a reasonable mileage overall.

You did the right thing in slowing down on the return leg as higher speeds use proportionately more range - especially in the cold.

Next time however, you could use the seat heaters over the cabin heat to save range, and also start with a nearly full battery, closer to 310 miles of range, and go slower on the outward leg, these would give you more leeway on the return trip to use the cabin heating and also overcome the losses due to the other factors.

And of course, if you know you're going to recoup most of the uphill losses on the long downhill, you won't be so concerned when you see the range left is under 100 miles left at the top of the hill!

ColoDriver | January 4, 2019

Similar experience driving the Fairplay from Lakewood. The 90 outbound miles use 140 miles of range, 90 miles back uses only 60. The 5000 foot elevation difference is the killer.

Once the Idaho Springs or Wheat Ridge superchargers open then it's drive it like you stole it time. Until then there are also chargepoint chargers in the Denver West office park right on I-70 and Tesla destination chargers at the Golden Hotel and at a real estate agent in Golden; slow but better than cold hands.

Mike UpNorth_ | January 4, 2019

@mrburke

Interesting theory. I like it.
I'll look for this when I put a warm car/battery down for the night in very cold weather and test it out.

jwins | January 4, 2019

8@draymond Glad you made it back under your own power, and thanks for sharing the details of your trip. As I was reading, I figured you’d get a lot of range back on the downhills, though your temp and speed adjustments helped as well. Like @Jiver, I wondered why you didn’t just go to Silverton and add 50-60 miles of range, but I appreciate the learnings from your not having done that.

@greg Thanks for the additional and very detailed analysis.

Steven.Haver | January 4, 2019

Just adding another data point since we drove from Denver to the Fraser Tubing Hill and back yesterday:

On the way up usage was high. I didn’t take a photo of it so I’ve forgotten the exact figures but at times the average was in the 500s. The ascent of the pass itself took about 10% (each time). Got about 2% back from the top of Berthoud pass going into Fraser (and from the top down to Empire on the way back).

Coming back I intended to reset trip A at the summit of the pass but forgot until probably 2/3rds of the way to Empire. Still, my average was negative all the way to Floyd Hill (where highway 6 exits the canyon and the left lane is always open for passing :-) ). When we got home to Denver the average was only 111. So it’s roughly double going up and half coming back.

Idaho Springs supercharger would be nice. In the meantime, don’t forget that Beau Jo’s has a nice 7kW level 2 charger. By the time you eat your pizza you could probably get to Park Meadows easily.

Jiver | January 5, 2019

@Steven.Haver Thanks for the data point. How much buffer did you have when you got back to Denver?

jjgunn | January 5, 2019

I read the title of your post & knew immediately it was uphill vs. downhill.

Used about 225 miles of range for 184 actual miles.

Pretty cool right?

Neomaxizoomdweebie | January 5, 2019

FYI - In order to climb 5800 feet in a 1900 Kg Tesla you must expend about 33 MJ of energy in addition to what is expended covering the 92 mile distance. Therefore, traveling at 60 Mph consumes an additional 9150 Wh, (or 99.5 Wh/mile). When you tack that onto the 240 Wh/mile to travel horizontal one can see how your trip results make perfect sense.

Steven.Haver | January 5, 2019

@Jiver
We were planning to stop at Beau Jo’s on the way back anyway, so I wasn’t worried about it at all so I don’t have exact figures. We left Denver with 80% charge. Got to Fraser with about 40% remaining. Got to the top of the pass (on the way back) with about 30%. Had around 28% when we got to Idaho Springs and probably got back about 7% while we were stopped for dinner (~1hr). Got home with 34%.

I’ll try to keep more exact records next time for posterity. :-) I had a Leaf for 3 years, so I got over my mountain range anxiety a while ago. We may make another trip this week though, so I’ll be sure to take photos and report back.

Tom11-18 | January 5, 2019

I would be very interested to see what the 'trip' estimator had to say. I used the navigator, input a destination and the trip computer told me how long the trip would take and what percent charge I would have when I arrived. It was amazingly accurate, it guessed the exact percent charge remaining for a trip over 100 miles into the Catskill mountains. On my return trip it was just as accurate, so it was taking the elevation difference into account.

Mike UpNorth_ | January 5, 2019

@mrburke

It's a no go on the theory. Parked my car at home around 4pm - full Regen available (warm battery) - SOC 75%.
4 hours later - currently 30 degrees - SOC still 75%.

Still not sure why OP battery dropped 4% in 6 hours.
Could the car have been searching for wifi constantly?

mrburke | January 5, 2019

@Michael

My test had different results
Friday evening arrived home with 256 mile range. (I charged at work)
3 hours later - temp in low to mid 40s 253 mile range. Loss of three miles in three hours.
Saturday morning - Temp in the mid 40s. 251 mile range - loss of two miles in 12 hours.
Saturday evening - Temp around 50. 250 mile range - Loss of 1 mile in 8 hours.

Unscientific -yes, but the data shows that fastest battery drain was from a warm battery getting cold.
Once again - it is only a single test. Not proof, but interesting.

mrburke | January 5, 2019

@Michael - Also SOC (State of charge ?) could be a different measurement than range remaining.
If the computer sees that the batter is cold, it may base range on less efficient battery.

Teslanene | January 5, 2019

I had similar experience, went to soda springs Ca elevation 6000ft. I stop in Rocklin super charger before heading up. I super charge to 230, travel like 60 miles but lost 100. On the way back only lost 30.

Mike UpNorth_ | January 5, 2019

Mrburke

Correct, my display shows State of Charge % (SOC) instead of estimated remaining miles (a conversation why for another thread).

I concede that I will switch back and conduct the test again with remaining est miles. Could the car's est miles remaining be based on current Wh/mi and battery temp but not when the display shows SOC/%? Yeah, I guess it could. IMO it would/should act the same weather its %/SOC display or miles remaining.

Now, OP said he lost 12 miles or ~3% SOC in 6 hours.
By your posts above you lost 6 miles a or 2% SOC over a 24 hour period. That sounds more like vampire/normal drain to me.
Again, OP's battery loss seems excessive/abnormal to me.

Now, I'm probably going to prove your point here....as I'm writing this...Just checked on my car again and its at 75% SOC. Which means since I parked in the cold (~30 degrees) ~7 hours later - I've lost 0 to vampire drain......Now I'm starting to think you are right....Vampire drain is really more like the car predicting miles left based on a warm battery when you park the car - as the car sits and the battery gets cold it starts to factor that into miles remaining....Where as SOC/% doesn't really change.......Or am I now confusing myself????

Gonna have to test this again with miles remaining not %/SOC......Good convo. Happy Saturday.

Mike UpNorth_ | January 5, 2019

Hopefully my post makes sense...sorry, its late here in the Midwest.

Mike UpNorth_ | January 5, 2019

Mrburke

Okay, here's an easy test.....with a cold soaked battery let's switch display from %/SOC to miles remaining......if SOC is, let's say, 50% and miles remaining is different than 155 there's something to your theory.

wwu123 | January 6, 2019

To put the 33 MJ of energy that alex53miller calculated for the elevation, that's actually 9 kwh when expressed in different units. That would be about 36 range miles at typical Model 3 efficiencies, but in actuality even more since potential energy won't have the battery chemical and drivetrain conversion losses, I'm guessing about 10% more so more like 40 range miles.

So the OP really used about 135 range miles to travel the 92 mi distance going (and 40 range miles invested in eelvation). On the return, the battery started out cold, but probably still had close to 100 range miles once warmed up, so 100-52 = 48 range miles used + 40 range miles recovered from elevation = 98 range miles. So elevation is the biggest SINGLE factor - but it's not a loss, it's a shifting of apparent energy from one leg to another, hidden in the elevation of the car.

That leaves 135-92 = 43 addtional range miles expended on the outbound leg, 98-92 = 8 range miles expended returning. As others have mentioned, I think cabin heating, and then higher speeds, caused more of the range mile losses going. On the return, cold battery initially caused some range mile losses before it warmed up, probably more than the actual 8 range mile - but OP gained additional range mile efficiency by traveling 45-55 for long stretches.

The energy conversion from elevation I believe is quite efficient, however, if coming down, if the mountain is so steep or speed so slow that you're capturing some as regen into the battery, then you will lose some of that energy in drivetrain regen losses. To get the most efficiency out of that energy going downhill, you need to avoid regen losses - i.e. have the accelerator pedal pushed down enough to where you're at least coasting or accelerating without regen indicated on the display.

HighlandPony | January 6, 2019

My daily work commute is 40 miles round trip. Usage on the way to work is ~2 miles, return trip ~38. Change in elevation is ~3000 ft. No mystery here.

mrburke | January 6, 2019

@Michael - Naive question. How do I display %SOC instead of estimated miles remaining ?

Mike UpNorth_ | January 6, 2019

Mrburke

I asked the same question here a while ago so no worries :)

I can't remember exactly where. Maybe display options? Or somewhere in the battery screen? I can't remember off hand. But if you dig you'll find it.
I think it's also where you can change time from 24 to 12 hours.

kcheng | January 6, 2019

According to abetterrouteplanner, your result doesn't seem unreasonable. Would be nice if you'd used percentages and Wh/miles. But according to ABRP, if you'd started at 90% SOC, 15degF, you'd average about 413Wh/m, and arrive with 39% SOC. Returning home, you'd end up with about 16% SOC, at 190Wh/m if you drove 55mph.

Like others, maybe a stop at Silverthorne for a quick early 5m fill, or better yet, rerouting thru Boulder for a quick fill if you feel low on the way home? ABRP lets you fiddle around with some ideas, before you go, so you can see how different factors affect your range.

norton.bittencourt | January 7, 2019

184 miles round trip ( 92 miles with 5000 ft elevation gain + 92 miles down hill)
Started with 275 miles of estimated range
Finished with 52 miles of estimated range
actual / estimated miles used 275-52 = 223 miles

6 hours parked by the pass with temperature ( I guess) 32F OR LOWER.

PERFECT!!!

The Model 3 give us much better estimations if you compare to our old needle/gasoline meter. Remember that the first half would point to a much larger range than the second half of the tank(?).

I LOVE THIS CAR!!!