Real-world range anxiety - first experience!

[Max*]

When and how could the remaining % energy be negative?

I don't understand the question? It can be WAAAAAAAY negative, try navigating somewhere when you're low on SOC, it'll tell you you'll get there with a negative SOC (assuming the SpC is further than need to go). I've seen -25% IIRC, but the latest update seems to now show just "--%" not a huge negative number, but maybe it's just a coincidence of when I looked.

I forgot exactly what happened at that screenshot, I think it started off as -1%, when I started driving it hit -3%, and when I got to the SpC it was +2%.

 

[smsprague]

FYI as far as units of measure goes, the U.K. uses metric for everything EXCEPT beer AND driving (motoring for true Anglophiles).

As a citizen and frequent traveler of both countries I am sure I am correct here.

All driving is still mph and miles. Yet gas (petrol) is sold in litres (liters to us in the US and Canada). Even the spelling is different!!

Go figure.

Absolutely correct. Another interesting point is that in the same Pubs that sell beer using imperial, spirits are sold using metric.

 

[ItsNotAboutTheMoney]

No they don't. They switched to metric years ago, except for pints in bars.

However, like Canada years after the switch to metric people still go back and forth on which system they're using depending on context and habit.

Road distances are all still signposted in miles, although dual measurement in some places. It would be very expensive to switch them all over.
But, short distances, e.g "roadworks in x units", are given in metres. They were given in yards when I was young (not feet as is used in the USA).

That's pretty much all that seems to be left now. I'm from the UK, and grew up educated metric but thinking imperial. Having moved to the USA, I'm even more imperial.

 

[AWDtsla]

Even after 18 months it's hard to judge. I was at the Casa Grand, AZ Supercharger last night and going from there to Prescott, AZ. 150 miles - 5,000 foot climb - all freeway - most of it a 75 MPH limit - 65 degrees no wind. Charged to 210 miles, car said I would make it at 180 miles. I was not worried because there is another Supercharger 45 miles from Prescott right on the way (Cordes Lakes). Had to stop, would have been 20 miles short. Went the speed limit to 5 MPH over. Any slower is dangerous on Arizona roads.

30 mile buffer? Who would do this even in an ICE? I've had cars where it refuses to tell you how much range you have left after you drop to 30 miles.

If you can't get there with 60 miles left, you should worry.

 

[smsprague]

30 mile buffer? Who would do this even in an ICE? I've had cars where it refuses to tell you how much range you have left after you drop to 30 miles.

If you can't get there with 60 miles left, you should worry.

I think you missed the point. There was no reason to wait the long time that it takes to get from 210 to 240 at a Supercharger because there is another one right on the way. Just pointing out how much more you can use than you think. I also think the Tesla Navigation leave a 10% buffer, so I really had a 55 mile buffer which is close to your 60 rule.

 

[AWDtsla]

I think you missed the point. There was no reason to wait the long time that it takes to get from 210 to 240 at a Supercharger because there is another one right on the way. Just pointing out how much more you can use than you think. I also think the Tesla Navigation leave a 10% buffer, so I really had a 55 mile buffer which is close to your 60 rule.

No I didn't miss anything. You can't actually use it without increasing your probability of falling short. Some people like to do that, fine. However, I have not seen my nav ever leave a buffer. It's usually underestimating usage, and if you consider stop times it's _really_ underestimating usage. Also a 0 mile buffer is also a myth. You may get lucky with the battery calibration, or you may get unlucky, which means you can't even get to 0 before you run out of charge.

 

[smsprague]

No I didn't miss anything. You can't actually use it without increasing your probability of falling short. Some people like to do that, fine. However, I have not seen my nav ever leave a buffer. It's usually underestimating usage, and if you consider stop times it's _really_ underestimating usage. Also a 0 mile buffer is also a myth. You may get lucky with the battery calibration, or you may get unlucky, which means you can't even get to 0 before you run out of charge.

So your point is the Tesla Navigation sucks. I agree. [emoji3]

 

[Whitmarsh]

Road distances are all still signposted in miles, although dual measurement in some places. It would be very expensive to switch them all over.
But, short distances, e.g "roadworks in x units", are given in metres. They were given in yards when I was young (not feet as is used in the USA).

Yes, we managed to keep the Buggers of Brussels' hands off beer (tap/draught), roads and speed. But you get some amusing combinations, like 5 metres of 2x4 because there's still a lot of old machinery in use.

That's pretty much all that seems to be left now. I'm from the UK, and grew up educated metric but thinking imperial. Having moved to the USA, I'm even more imperial.[/QUOTE]

 

[jerry33]

Road distances are all still signposted in miles, although dual measurement in some places. It would be very expensive to switch them all over.

Brute force switching to metric ruined Canada's economy for years.

 

[brec]

Once again today I had a rapid drop off of predicted charge remaining at destination (PCRAD) that caused me to slow down, and I don't know why. I left the Rocklin, CA SpC, headed for the Fremont, CA SpC, with a SoC of 71% and PCRAD of 16%. In less than 20 miles the PCRAD was 6%. I slowed down and that stabilized it, and it slowly increased to 10-11% at which point I sped up to my original speed. PCRAD increased further to 13%, where it remained until Fremont.

It was raining at the start of the trip, maybe more than it was later on, but not so much so that I can be sure. Per http://matesla.ca/headwind.html?unit=imperial there was no significant change in winds.

Max*, how often when you start with a 10% PCRAD do you decide to slow down due to a divergence between actual and predicted consumption?

 

[AWDtsla]

2 data points from today's driving:

1. Nav does NOT pick the most energy efficient route. After I drove past I turn because I wanted to take a different way, predicted energy at destination went UP!

2. Drove without heat on in 40F weather, then turned the heat on several hours later around 27F. This pretty much destroyed predicted energy at destination. So it's either using past consumption as an input, or it's just very wrong. Although I did a napkin calculation of what I expected to end up home at before leaving, and I was within 5 RM of actual. In the middle of this drive, I decided that I needed to come out of range mode because my feet were freezing. I also noticed that rear vents were not working at all. I don't know if there are sensors back there, but n matter what I did the rear vents would not come on. Regardless, it's pretty sh**** to have to disable all of range mode just to warm yourself up, although I've already complained about this several times. Not to mention it was only "barely winter" cold.

 

[Max*]

Once again today I had a rapid drop off of predicted charge remaining at destination (PCRAD) that caused me to slow down, and I don't know why. I left the Rocklin, CA SpC, headed for the Fremont, CA SpC, with a SoC of 71% and PCRAD of 16%. In less than 20 miles the PCRAD was 6%. I slowed down and that stabilized it, and it slowly increased to 10-11% at which point I sped up to my original speed. PCRAD increased further to 13%, where it remained until Fremont.

It was raining at the start of the trip, maybe more than it was later on, but not so much so that I can be sure. Per http://matesla.ca/headwind.html?unit=imperial there was no significant change in winds.

Max*, how often when you start with a 10% PCRAD do you decide to slow down due to a divergence between actual and predicted consumption?

Once in 8 months worth of trips (17.5k miles and counting). It was cold, and windy, and my destination SOC was dropping like a rock, sop i slowed down to the speed limit for a little while before it stabilized.

I've never slowed down below the speed limit. Never. Though the North East speed limits only go to 65.

 

[Soolim]

I don't understand the question? It can be WAAAAAAAY negative, try navigating somewhere when you're low on SOC, it'll tell you you'll get there with a negative SOC (assuming the SpC is further than need to go). I've seen -25% IIRC, but the latest update seems to now show just "--%" not a huge negative number, but maybe it's just a coincidence of when I looked.

I don't understand the concept of negative remaining energy in the battery, leaving the anti-bricking reserve aside.
You mean the remaining energy estimate is inaccurate; that you can reach a destination with negative energy remaining in your battery?

 

[Max*]

I don't understand the concept of negative remaining energy in the battery, leaving the anti-bricking reserve aside.
You mean the remaining energy estimate is inaccurate; that you can reach a destination with negative energy remaining in your battery?

No, you can't reach a destination with a negative charge, I don't think I ever implied that. When you see a negative number it just means you would have needed an extra X% at your current rate of travel to arrive at your destination. It basically tells you to slow down. Also while you're SpCing it'll show you the negative number turn into a positive number.

I love that it tells me HOW negative I'm going to be if I drove off right away. I guess you would prefer something that says "don't drive, you wont make it", but then it doesn't give you an idea of how much you wont make it by. I can drive off with -3% and drive below the speed limit and make it, but without giving me an exact negative number, I'd be clueless. (not that this is something I'd ever want to do, just giving an example)

 

[Fanatic1]

Well, I had my first proper experience of “Range Anxiety” this weekend! We went up to Scotland (UK owner, here!) for some snowboarding, and the car (Tesla Model S) had performed faultlessly throughout, and charging all the way there and whilst there and been a doddle.


However, on the way home (London) the weather was pretty poor; heavy rain with standing water, around 2’C, at night and with a 20mph headwind. This is pretty much worst case range-wise; the cold weather reduces battery range, being at night and in the rain requires both lights and wipers, and of course both a strong headwind and standing water increase drag substantially. Add to that 3x motorway closures and the resulting diversions, and everything was working against us.


So we set off from Gretna Green Supercharger with around 220 miles of charge, aiming for Stoke Supercharger (Keele Services) 160 miles away. So we had 60 miles in hand. Soon it became apparent this was not enough, as the car advised to drive at 65mph, and then 60mph, to reach our destination. Realising this was cutting it a bit too fine, we then diverted to the more-northerly Warrington Supercharger, 136 miles away. Long story short, driving ultra-conservatively (64mph), no heated seats on, minimal air-con (heating) to stop the car misting up and even turning the headlights off so DRL-only on the lit sections of motorway, we eventually made it to Warrington with 6% (14 miles) battery range remaining! Needless to say, we were very relieved to get there!!


I don’t blame the car particularly, a combination of weather/road conditions and diversions were bound to reduce the range beyond the ‘Typical’ figure given. However, what I do question is how ‘typical’ this figure is? It strikes me that the range figure given as ‘typical’ is more likely ‘ideal’ in reality, and any deviation from those ideal parameters, be that speed, weather or road conditions can have a pretty dramatic impact on actual range!


Anyone else had a similar experience?!

For this longer trip, do you charge to 90% or full charge to 100%?

 

[Soolim]

No, you can't reach a destination with a negative charge, I don't think I ever implied that. When you see a negative number it just means you would have needed an extra X% at your current rate of travel to arrive at your destination. It basically tells you to slow down. Also while you're SpCing it'll show you the negative number turn into a positive number.

I love that it tells me HOW negative I'm going to be if I drove off right away. I guess you would prefer something that says "don't drive, you wont make it", but then it doesn't give you an idea of how much you wont make it by. I can drive off with -3% and drive below the speed limit and make it, but without giving me an exact negative number, I'd be clueless. (not that this is something I'd ever want to do, just giving an example)

Thanks. I will use it on my next road trip.

 

[Mike_C]

For this longer trip, do you charge to 90% or full charge to 100%?

We started with 100% as we were charging up overnight at home, although we didn't really need to to reach the first SpC. At the SpC's we only ever charged up to around 80-90%, it gets so slow to get to 100% when you doing a long tip you're often better to get going and charge at the next station for a little longer (i.e. you arrive with 20% rather than 30% because you started with 90% not 100%) as it charges so much quicker at that level.

The problem we had was we charged to 90% (220 miles range) but the 140 mile journey absolutely destroyed that typical range figure, due to the weather conditions.

FWIW, whilst in Scotland we charged to 100% overnight every night, just in case we got caught short the next day or couldn't charge overnight at the next location, as there's very few SpC's up there (nothing north of Edinburgh).

 

[SurferChick]

My first post after lurking on the forum for a while but this was one of my first concerns, I'm based in West Cumbria and looking to get an S in the next year.
The gap between Gretna and Keele is OK going South but Keele SC is only on the Southbound services so I'd have a problem coming back North when visiting our daughter at High Wycombe (in this case I'd turn off the motorway at Penrith)
However, I've looked at the Ecotricity site and with the number of Type 2 43kW chargers along the route, I've have calculated that I'll be OK with an extra stop to top up at one of those.

It looks as though these are at all services these days, so could always do that slower top up if needed.

Hi Altaa, I was wondering whether you are still able to go from Gretna to Keele? I'm looking at doing similar distances. And are you able to exit on the Northbound Keele SC, drive across the M6 Three Mile Lane, and then exit via the barriers to the Supercharger on the Southbound Keele services?

 

[Cooker]

If you found the car's recommended speed starting to rise, you could then give it a little more go.

‘Recommended speed’? Does this appear in the trip predictor when low on juice?

 

[Todd Burch]

‘Recommended speed’? Does this appear in the trip predictor when low on juice?

It's been a long while so I'm not sure if current versions still do it, but at least in the past when your state of charge was low the car would say something to the effect of "Stay below xx MPH to reach your destination."

Edit:

I found this picture:

However, now I'm not 100% sure I remember whether the car recommends a maximum speed or not. I thought it did, at least at some point.