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Just a warning to new Tesla owners!

I am sure it has been discussed. But I am a VERY tech savvy individual. I took the car to northern Utah. It normally resides in Vegas. I was trying to make fast time home and DIDN'T take into account how much the car and battery heater eats up your battery! I stopped at Nephi supercharger - used the nav to see the next one. It was Beaver utah approx 100 miles. So being in a hurry - first mistake I made - I figured that charging to 155 should be MORE than sufficient. HAHAHA Little did I know!

I was watching the ratio deplete as I was heading south. It was 50% extra then 40% extra and soon it was near my nav destination number. I am also a private pilot, so I was starting to prepare for the worst. The numbers were depleting way faster than mileage to destination. At one point I was 14 miles shy of destination in the dash vs. nav. I decided it would be a great idea to draft behind a Semi truck doing 60 (the speed limit was 80!) I called Tesla - I usually enjoy a nice tech conversation with the boys. This one wasn't good. I asked him what the max travel after 0 on the dash was - because I was approaching zero VERY QUICKLY! He replied that that it varies but you can't actually count on ANYTHING!

I was climbing the last hill before the slight downgrade to the city. At this point my car said 0 - soon after - it said CHARGE NOW. While discussing with the Tech - I turned on range mode - I turned off all climate control and I was essentially 14 miles away from the supercharger. This is about as close to running out of gas in a plane as I have every been! I was advised by a friend that coasting is more efficient than regen - so coast I did. (I was doing 40 approx in an 80 MPH freeway section - with my hazzard lights on of course!) Keep in mind 14 miles to go. I babied that thing as much as humanly possible thinking every mile I saved was a little less tow bill. I was keeping my average watts per mile near 100! I took a bunch of pictures along the way - because that's what tech nerds do. Longer story short - I MADE IT!

I plugged in and it was charging like a bat out of hell! I wish someone would have warned me that in colder weather the vehicle heater and battery heaters take A LOT OF POWER! So my words to the wise! Stay a little longer at the charging stations in colder weather! If you plan on driving higher speed limits especially! I had fellow tesla owners praying for me. To this day I don't know how I made it! The ironic thing was - I was sitting there charging in station 1b and someone pulled up in 1a - I explained that I was VERY dead and it would help both them and I to charge faster. To which he replied - my car is dead - I coasted in to the charging station! His was COMPLETELY dead! I helped him push it in to 1a and it BARELY had enough juice to start charging and release the maglock on the charge port. His battery was so dead it only charged at 3 amps for about 10 mins! Although it made me feel a little better I wasn't the only one that underestimated - I feel an obligation to help people understand. Especially because if you run out in severe cold it could be REALLY bad! Needless to say since his car BARELY started charging - I moved to station 2.

My new rule of thumb is if its cold outside and you don't want to drive like a grandma - HAVE DOUBLE THE RANGE YOU THINK YOU NEED!

If I help one person understand it was worth it! Be safe out there!

AJ
 
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Great story, thanks for sharing!!!

Bottom line is, you made it, and now it makes for an awesome story to tell your friends. It also shows how good the battery is, and how well engineered the car is! You were 14 miles short, and yet, by employing some easy techniques, you were able to make up this shortage. I am amazed! Desperate times call for desperate measures (100wh per mile - nice)

And yes - paragraphs, please!

J.
 
Perfect example of why tesla needs to share evtripplanner.com with all new owners. Shoudld be essential. People don't realize The effects of terrain, weather speed. Etc...even though they are the same effects in gas cars, just they had more exits with gas stations than we currently do with superchargers at the moment.
Tesla needs to add elevation, speed etc... To the navigation. As More and more people that are not tesla fanatics get into the model s and x world this is going to be more and more an issue. As people are not used to planning like this. Which is very easy, but takes an effort, when it should be in the car navigation.
 

Saghost

Well-Known Member
Oct 9, 2013
8,224
7,100
Delaware
Perfect example of why tesla needs to share evtripplanner.com with all new owners. Shoudld be essential. People don't realize The effects of terrain, weather speed. Etc...even though they are the same effects in gas cars, just they had more exits with gas stations than we currently do with superchargers at the moment.
Tesla needs to add elevation, speed etc... To the navigation. As More and more people that are not tesla fanatics get into the model s and x world this is going to be more and more an issue. As people are not used to planning like this. Which is very easy, but takes an effort, when it should be in the car navigation.

This does seem like an obvious one for Tesla. The car has always active cellular to reach the web, and the information is available between the EV planner, any of the various weather forecasts, and Tesla's information about consumption at speed.

They should be able to build an extension for the navigation that figures out how much energy you need to cover the distance to the next supercharger at a given speed. I'm thinking they should extend that, and not only have the car plot a string of Superchargers to get you were you're going, but also place charge needed bars on the battery while Supercharging on one of those nav routes - for bonus points, give the driver an estimated time to charge when they pull in based on that charge level.

As more folks use the network, this can help Tesla further - if they pass the navigation plans back to a central computer, that computer will know when a bunch of people are planning to be at the same Supercharger at the same time - and just like traffic navigation, the car could give you options to adjust your route and bypass the backup (charge higher at an earlier stop and skip the one with the backup or equipment failure.)

This can also be tied in to Autopilot as that matures, so it automatically picks the most efficient speed for your route within your guidelines and drives from one supercharger to the next.

It seems like a big opportunity for Tesla to redefine the roadtrip and make it both quicker and more convenient. :)
Walter
 

Cottonwood

Roadster#433, Model S#S37
Feb 27, 2009
5,089
181
Colorado
Glad that you made it!

That is a tough stretch with a climb, high speeds (77 mph average traffic), and winter temps. As others have said, EV Trip Planner is a very good planning tool for estimating the battery energy needed for a trip segment. Make sure that you put in all the parameters correctly, and remember that the speed multiplier is a multiple of average traffic speed, not the speed limit.

Here are the results for your run assuming 20˚F. outside air temperature:

N-Beaver.png


That is 178 Rated Miles (RM) needed for a 115 mile run!

As you have painfully learned, cold weather and high speeds suck the energy from the battery. I think that the speed limit for some of I-15 south of Nelphi is 85 mph. Because losses to aerodynamic drag go as the square of speed, the aero losses at 85 are about twice the losses at 60 mph!

I STRONGLY recommend using EV Trip Planner for segments that you have not done before, mountain runs, cold temps, etc.

Enjoy your Model S!
 

CmdrThor

Active Member
Jul 24, 2013
1,102
903
Marietta, GA
A few thoughts .. congrats on making it to the supercharger.

Obviously hindsight is 20/20, but turning on range mode near the end of your journey doesn't help nearly as much had you turned it on earlier (of course if you knew the trip was going to take so much power, you would have stayed 10 more minutes at the supercharger and been fine :) ).

Drafting a semi may have helped you reach the supercharger, but it could have cost you your life. I would rather get a tow to a supercharger than take the higher risk of an accident by drafting.

Hopefully the new firmware that is supposed to tell you how much energy you need to get to the next supercharger will take temperature into account and we will reminisce about the year 2014 when Model S couldn't tell you the exact amount of charge you would need in the cold. Based on the fact that January 2014's Coast to Coast rally almost certainly had such software planning their trip, it is surprising that it hasn't been released yet in December 2014.
 
...Make sure that you put in all the parameters correctly, and remember that the speed multiplier is a multiple of average traffic speed, not the speed limit...

Thanks for sharing this. For all the times I've use EVTripPlanner I did not know this really important fact! It actually irritates me a bit because I don't know the average traffic speed on a given stretch of road so now I can't effectively estimate what to put in that field. It also explains why I thought it was off by about 10% in the range estimates.
 

Cottonwood

Roadster#433, Model S#S37
Feb 27, 2009
5,089
181
Colorado
Thanks for sharing this. For all the times I've use EVTripPlanner I did not know this really important fact! It actually irritates me a bit because I don't know the average traffic speed on a given stretch of road so now I can't effectively estimate what to put in that field. It also explains why I thought it was off by about 10% in the range estimates.

If you click on the "details" tab over the map, you can see time, average speed, distance, etc for each road segment. When I want to hypermile a trip, turning down the speed multiplier to 0.9 or 0.8, I look at those average speeds to have an idea of how fast to drive.
 

ecarfan

Well-Known Member
Moderator
@Moorehead, I'm glad to hear that you made it to the SC. It sounds like you are a new owner. There have been numerous discussions in these forums over the past 14 months which make clear that cold weather and going uphill use far more miles than the "rated miles" figure shown in the drivers display screen. Based on your description of your trip it sounds like you watched your extra miles drop rapidly but did not slow down or reduce cabin heating until your extra miles had vanished. At that point you had to take extreme measures such as drafting semi trucks, which is very risky in my opinion. Spending another 15 minutes at the Nephi SC would have made the trip easy.

Hindsight analysis by me sitting in my easy chair at home is of course readily done. You had to get through a very stressful situation and I'm glad it turned out okay for you. My purpose in pointing out the obvious is to try to minimize the chance that some blogger will read your story and write something stupid online about how Tesla's are dangerous to use during the winter or worse.

So lesson learned and I'm sure in the future you will avoid getting into situations where you have to run the car down to zero miles.

And I agree with others that the in-car navigation could do a much better job of calculating energy requirements to reach the next SC and warn the driver of potential problems. I was disappointed that firmware V6 did not include such enhancements but am confident that improvements are coming.
 
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AudubonB

One can NOT induce accuracy with precision!
Moderator
Mar 24, 2013
9,235
41,597
TO COTTONWOOD and other evtripplanner cognoscenti (and maybe I should make this into a separate thread but there is a fine story on this one):

Is there a way in which one can feed into that platform all the other data, and ask of it "at what speed can I then safely arrive at my intended destination?" That would seem to me a very useful way to trip plan.
 

Cottonwood

Roadster#433, Model S#S37
Feb 27, 2009
5,089
181
Colorado
Here are the results for your run assuming 20˚F. outside air temperature:

That is 178 Rated Miles (RM) needed for a 115 mile run!

As I like to say, hindsight is 20/20, or for our metric friends, 6/6.

Those numbers above were for a speed of 1.0 and external temps of 20˚F, in an 85 with 19's. I did a couple of more runs.

For external temps of 72˚F, the RM need is 153, so even at normal temps, that is a needy segment of road because of the high average speeds (77 mph). Your departure on that segment with 155 RM in the battery would have been close on a good day.

For grins and with a lot of desktop hindsight, I tried a temp of 20˚ and a speed multiplier of 0.85. That brought the RM need down to 154, but needs 16 minutes more drive time. That 16 minutes on the Nelphi Supercharger would have been worth 50-70 RM, so the time would have been better spent on the Supercharger. This is all hindsight, but worth learning from.

Once again, glad you made it!
 
Thanks for sharing this. For all the times I've use EVTripPlanner I did not know this really important fact! It actually irritates me a bit because I don't know the average traffic speed on a given stretch of road so now I can't effectively estimate what to put in that field. It also explains why I thought it was off by about 10% in the range estimates.

For the most part you do not need to put anything in that field. So nothing to change, average speed normally is at speed limit to 5 mph above speed limit as it is how people drive. So the example above, with zero changes to the settings would have yielded the 178 rated miles used.
We will have more and more of these situations for newcomers as sales continue at this Pont. Must hope the media does not jump on board and discredit peoples planning skills as something tesla is failing.
 

Cottonwood

Roadster#433, Model S#S37
Feb 27, 2009
5,089
181
Colorado
Is there a way in which one can feed into that platform all the other data, and ask of it "at what speed can I then safely arrive at my intended destination?" That would seem to me a very useful way to trip plan.

There may be a way to do that, but I don't know how. Make a suggestion!

After the first run on a route, successive runs are pretty quick. I usually just twiddle the Speed Multiplier knob and interior temps to find a result that works for me. The "details" tab has a lot of good info, and you can even download a CSV file into your spreadsheet if you want.

As most of us say, Your Mileage May Vary...but if you drive in a reasonably smooth manner that matches reasonable inputs to EV Trip Planner then I have found its predictions pretty good. Unmodeled range killers to watch out for are things like big headwinds, temperature drops, wet/slushy roads, and the need for lots of front defrost.
 

ckessel

Active Member
Jan 15, 2011
4,455
405
That is 178 Rated Miles (RM) needed for a 115 mile run!
+1 on Cottonwood's whole post, but I wanted to highlight this because 1.5x range required is the rule of thumb that came out of some previous threads for "worst case" scenario usage. This case pushes that just a touch beyond 1.5, but at 1.5 you'd probably been fine and just had to slow down a little if things got tight.
 
See, this points to an issue that I wish Tesla would address.

I would like Tesla to aggregate data from Model S's traveling between superchargers, and take into account weather (temp, wind, precipitation) and topography conditions, as well as speed, SOC, and energy use.

Mix that all together and provide guidance to the driver IN ADVANCE of their leaving a SuperCharger. When they pull into a SuperCharger, suggest how much they should charge the battery based on recent other drivers heading the same direction. If the driver charges less, warn 'em when they unplug -- "Current conditions suggest you charge to 260mi before heading to [insert next SC here]".

Tesla has shown they know how to aggregate data from the car --- they did it with the air suspension feature that came out in 6.0. (Meaningless to me since I don't have the air suspension.)

This kind of feature would be vastly more helpful. Especially to newbie Tesla owners -- as the car gets more mainstream and the owners become less techie/early-adopter oriented (we've all seen the newbies at SCs, not knowing what to do or whether to back in or not, or how to plug in, and how long to charge, have we not?), this kind of guidance would be helpful to all.
 
...

That is 178 Rated Miles (RM) needed for a 115 mile run!

As you have painfully learned, cold weather and high speeds suck the energy from the battery. I think that the speed limit for some of I-15 south of Nelphi is 85 mph. Because losses to aerodynamic drag go as the square of speed, the aero losses at 85 are about twice the losses at 60 mph!

I STRONGLY recommend using EV Trip Planner for segments that you have not done before, mountain runs, cold temps, etc.
Enjoy your Model S!
+1 Cottonwood. I've use EVTripPlanner on every long trip over an unfamiliar route. It's a useful and fairly accurate app. The site is the creation of a young programmer accepting donations towards his college fund (14 days of Stanford tuition donated so far). I encourage all who find it useful to donate something.


(full disclaimer: I have nothing really to disclaim. No association with the site's creator. I donated though).
 

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