built in exta mileage with in the battery?

[WarpedOne]

40 miles of buffer may sound plenty but over 160 mile planned trip this is only 25% 'reserve'.
As you found out, that may not be enough.
I recommend at least 30% reserve and/or contingency plan - investigate charging opportunities.

 

[Cottonwood]

So I had my first experience yesterday with running out of range. headed north to Albany SC into a severe headwind with a 40 mile buffer. 200 mile range (60 kW Model S) and 161 miles to go. Usage was average around 341 w/mi due to headwinds average 25 to 30 miles with gusts up to 45 mph. Crappy day for a road trip in the Model S. Did find a few cars to draft for about 50 miles, which got me within 6 miles to go when I now had 0 range. The Charge Now came up on the range (wasn't taking photos as I was quite nervous now) and the yellow bars on the kW side of the speedometer were now around 60 k limiting power. Amazingly, I was able to drive 6 miles beyond zero to the Albany SC.

Not going to do that again. But I can confirm that I drove six miles beyond zero. I drove around 45 to 50 mph for the last ten miles (+4 to -6), very conservatively not pushing the car or letting the accelerator draw hit the yellow bar on the kW scale.

When I pulled in to the SC stall, said a quiet thank you and saw that I had used 54.8 kw of charge on the battery. Don't know what is left behind so you don't brick the 60kW battery, but I had started shutting off running lights and radio (of course, I never used the heat the whole way or defrost while driving). Had done everything to minimize the drain on the battery other than driving.

Still am amazed I made it. Definitely need to plan better and check the weather forecast.

Glad that you made it!

Wind is a 4-letter word!!!

When you see the buffer/margin slipping away rapidly, even into a stiff head-wind, slowing down will help conserve your battery. The sooner that you notice that you will be in trouble and can slow down, the better, and the more energy that you will conserve.

 

[yobigd20]

So I had my first experience yesterday with running out of range. headed north to Albany SC into a severe headwind with a 40 mile buffer. 200 mile range (60 kW Model S) and 161 miles to go. Usage was average around 341 w/mi due to headwinds average 25 to 30 miles with gusts up to 45 mph. Crappy day for a road trip in the Model S. Did find a few cars to draft for about 50 miles, which got me within 6 miles to go when I now had 0 range. The Charge Now came up on the range (wasn't taking photos as I was quite nervous now) and the yellow bars on the kW side of the speedometer were now around 60 k limiting power. Amazingly, I was able to drive 6 miles beyond zero to the Albany SC.

Not going to do that again. But I can confirm that I drove six miles beyond zero. I drove around 45 to 50 mph for the last ten miles (+4 to -6), very conservatively not pushing the car or letting the accelerator draw hit the yellow bar on the kW scale.

When I pulled in to the SC stall, said a quiet thank you and saw that I had used 54.8 kw of charge on the battery. Don't know what is left behind so you don't brick the 60kW battery, but I had started shutting off running lights and radio (of course, I never used the heat the whole way or defrost while driving). Had done everything to minimize the drain on the battery other than driving.

Still am amazed I made it. Definitely need to plan better and check the weather forecast.

I have an 85 and barely made it to Albany from Edison. Only charged to 90% 230 miles and arrived with 3. So yea I used 227 miles to go 160 miles. Kinda crappy uphill. I was going like 75 to 80 though. Next time I'll max range charge it.

 

[Cottonwood]

I have an 85 and barely made it to Albany from Edison. Only charged to 90% 230 miles and arrived with 3. So yea I used 227 miles to go 160 miles. Kinda crappy uphill. I was going like 75 to 80 though. Next time I'll max range charge it.

Slowing from 75 to 70 over 160 miles will only cost you about 10 minutes, and gain you about 25 rated miles over that distance. Charging from 90% to 100% will probably take more than 20 minutes, and will gain you about 25 rated miles. Slowing down a little is usually better than 100% charging on a Supercharger.

 

[yobigd20]

Charging from 90% to 100% will probably take more than 20 minutes, and will gain you about 25 rated miles. Slowing down a little is usually better than 100% charging on a Supercharger.

Ooh but driving that slow just really huuurrrts and is painful for me to crawl. (Seriously I have a speed issue).

 

[HankLloydRight]

What is the optimal speed to drive to absolute maximize range? Wasn't there a graph from Tesla that showed that 45mph to 55mph was the peak of the efficiency curve?

Glad you made it to the Albany SC... it's not exactly right off the highway, so it's lucky it didn't die maneuvering around in that parking lot or those access roads. If only there was a way to hit a button to tell the battery "but I only need to go 400 more yards to charge!! I promise!".

 

[David99]

What is the optimal speed to drive to absolute maximize range? Wasn't there a graph from Tesla that showed that 45mph to 55mph was the peak of the efficiency curve?

It's on their blog somewhere. I think it's around 25-30 mph.

Part of it is the motor optimized for a certain speed but also the battery. The slower it is discharged, the more energy can be used because the internal losses are smaller at a lower rate.

 

[jvonbokel]

What is the optimal speed to drive to absolute maximize range? Wasn't there a graph from Tesla that showed that 45mph to 55mph was the peak of the efficiency curve?

Here's the blog post. The absolute ideal is probably around 21-22mph.

Model S Efficiency and Range | Blog | Tesla Motors

Part of it is the motor optimized for a certain speed but also the battery. The slower it is discharged, the more energy can be used because the internal losses are smaller at a lower rate.

I can confirm this from personal experience. When I completed the 400mi challenge, I used 77.9kWh and still had 3 rated miles remaining, which is a few kWh more than SarahsDad was able to eek out going all the way to zero rated miles. Of course, I had to average 194.4 Wh/mi (24.31mph) to do it.

Full gallery here.

 

[neandertal]

Given that the head wind was killing the drive, I figured that drafting at 65 mp would put less resistance on the car and get me faster to the SC. I was trying to get to western Mass that morning, so I wasn't really planning to drive @ 50 mph all the way. But, I would have been really late if I needed a tow to the SC :cursing:. Overall a very illuminating exercise and one I don't plan on repeating. Now I will wait to do this trip again until the Newburgh/New Paltz SC comes along.

 

[franknesss]

This sort of makes me wonder why Tesla just doesn't go with a battery percentage to display how much is capacity is left, and use the calculated projected range to show range. This way the battery percentage will match the projected range, based off your driving style.

jvon, were you able to get any picture of the Projected Range? (based off 30miles) I'm curious to the discrepancy between the projected range and rated range.

Here's the blog post. The absolute ideal is probably around 21-22mph.

Model S Efficiency and Range | Blog | Tesla Motors



I can confirm this from personal experience. When I completed the 400mi challenge, I used 77.9kWh and still had 3 rated miles remaining, which is a few kWh more than SarahsDad was able to eek out going all the way to zero rated miles. Of course, I had to average 194.4 Wh/mi (24.31mph) to do it.

View attachment 62984

Full gallery here.

 

[jvonbokel]

jvon, were you able to get any picture of the Projected Range? (based off 30miles) I'm curious to the discrepancy between the projected range and rated range.

You know, this sounds like something I'd do, but I just looked and apparently I didn't. I know I forgot to take shots of the trip meter for the first 100mi, so I guess I shouldn't be surprised I forgot to record some (any) projected range data. I wish they'd just include the projected range on the instrument cluster version of the energy graph. They could make it stationary in the space where there's more room (in the 0-300 Wh/mi area), and just draw an arrow that points to the avg line.

 

[David99]

This sort of makes me wonder why Tesla just doesn't go with a battery percentage to display how much is capacity is left, and use the calculated projected range to show range. This way the battery percentage will match the projected range, based off your driving style.

They kind of do. The energy usage graph does that. It allows you to use your average from the last 5, 15 & 30 miles to calculate your projected range. It actually is pretty accurate. I use it when I have bad conditions (head wind or rain) to see how far I will be able to go.

 

[jvonbokel]

They kind of do. The energy usage graph does that. It allows you to use your average from the last 5, 15 & 30 miles to calculate your projected range. It actually is pretty accurate. I use it when I have bad conditions (head wind or rain) to see how far I will be able to go.

In very early versions of the firmware, they allowed you to chose "Rated Range" or "Projected Range" for the number shown in the center of the speedometer. I'm not sure why they removed that option.

 

[franknesss]

I would like to have the projected range displayed on the dash instead of the screen though. Unfortunately, it seems like Tesla removed that option.

They kind of do. The energy usage graph does that. It allows you to use your average from the last 5, 15 & 30 miles to calculate your projected range. It actually is pretty accurate. I use it when I have bad conditions (head wind or rain) to see how far I will be able to go.

 

[wycolo]

Zero = Zero: Winter Cautions

Here is a pretty good test of going past zero on 6.0(1.67.28) with an S85 (mfr 07Dec2012). No headwind on slight but steady uphill grade at 22*F. 40 miles into the 135 mile trip I realised that I had set the charge limit 20 shy of what I intended (a 'winter' supplement) thanks in part to that Quija 'do you feel lucky today' charging scale. Thus I drove gently but had to deal with more packed snow than I had anticipated. Below 10 miles I really sensed failure so drove on the shoulder below 30mph. The last few miles were at 20-25 mph. Hitting 0 raised no messages so I pressed on gently hoping to reach the village. Within 1/2 mile message said Charge Now followed almost immediately by Car Shutting Down. I stopped and backed 60 feet into a wide side road which turned out to be the entrance to a concrete/gravel plant and put it into TOW MODE. Hooked up a rope to the trailer hitch and a company pickup pulled me up to one of the cables used for block heating. 115v 12A = happiness, or was it??

THE WINTER PART

Watching the charge screen promise "4 miles per hour" charge rate for over an hour without any tick up to even 1 mile brought on the realisation that battery heating is included in that figure so I may not be getting any additional battery charge at all!! No way to tell. After 2 hours called Service Center who opened with "we've been waiting for your call!" They know when one of their cars hits ZERO and can see it on the map (just 4 miles from Silverthorne SpC). They saw that my charge was up to 4.5%, oh it just ticked up to 4.7, and roughly might be equivalent to as many as 8 miles or so, but give it at least another hour. BTW you were down to 12.1v if you had hit 12.0 it would have been instant death!! Whew.

An hour later still no tick up above Zero. I did not think to dig out battery energy info- is it possible to read out % charge on the car's screens?

I charged for 4 3/4 hours at 115v 12A with the screen still showing 0. I had disconnected and turned the car around to maximize solar gain and then resumed charging but the 0 did not change. So I threw in the towel since it was down to 17*F and for all I knew I was achieving no net charging. Drove the 4 miles to the SpC with no miles, zero or otherwise, showing on the speedo. In its place was a red notice to CHARGE SOON or some such. Backed up into thick snow to a bad charger! The second try succeeded. Charge started at 0 but took a long time to jump to 1. Did not begin at a full 120kw but maybe half that rate. I failed to record data choosing to run for food before closing time.
--

 

[apacheguy]

An hour later still no tick up above Zero. I did not think to dig out battery energy info- is it possible to read out % charge on the car's screens?

You can have a web server read percent SOC and print it out to the touchscreen. That's what I do so I don't have to rely on the in car battery gauge.

Thats weird that 4% SOC wasn't even registering a rated mile. The way you make it seem, when you get down to 0 rated miles, the car quickly shut down. But when you go the other way (charging back up), the 0% should have been lined up with the 0 miles. I wonder if the SvC was including bricking protection?

 

[yobigd20]

You can have a web server read percent SOC and print it out to the touchscreen. That's what I do so I don't have to rely on the in car battery gauge.

Thats weird that 4% SOC wasn't even registering a rated mile. The way you make it seem, when you get down to 0 rated miles, the car quickly shut down. But when you go the other way (charging back up), the 0% should have been lined up with the 0 miles. I wonder if the SvC was including bricking protection?

I never thought about using the REST API and hosting a private little app in the cloud to view detailed stats via touchscreen. Nice...fairly simple to do too.

 

[AndreyATC]

I wonder if TM can simply integrate your destination to allow extra few miles below 0
The car knows it is about to approach supercharger or home (previously charged locations).
Why not just let few more miles to reach charging station, with some tolerance of 5-10 mile max
These batteries can probably survive extra percent of discharge

 

[David99]

I wonder if TM can simply integrate your destination to allow extra few miles below 0
The car knows it is about to approach supercharger or home (previously charged locations).
Why not just let few more miles to reach charging station, with some tolerance of 5-10 mile max
These batteries can probably survive extra percent of discharge

Because there is a good chance you can damage the battery permanently. In this very discussion we have seen that some people don't understand how bad it is to run the battery down to 0 especially when drawing a lot of power from it while doing so. People will just assume that the car will allow them to get to the next Supercharger, no matter what and floor it. The reason why Tesla is able to give us a very comprehensive warranty on the battery is because they protect it from being damaged.

As many people have reported, you can go passed 0 and you can go quite a bit when you take it easy on the accelerator. I have been able to go 9 miles passed 0 once. I saw it coming, I slowed down and drove carefully. The car allowed me to go further. Why? Because it doesn't shut down at 0, it shuts down when the battery level reaches a critical level. The easier you are on the battery, the further you can go.

 

[AndreyATC]

David,
part of the feature could be limit of 30-40kw power
kind of like limp mode