Real-world range anxiety - first experience!

[Patrick W]

I find it interesting that you're using miles as your unit of measure . . .

But, thanks for sharing your story!

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+1 My thoughts exactly!

Yes. I thought everyone but US had evolved past the old units of measure.

Still, I'm glad you made it ok.

 

[Mike_C]

Check the EVtripplanner.com site, Its very accurate and allows for modification of driving speed and temperature. You can also check for variations in the weather based on headwinds. The only thing you can't anticipate is road closures.

Also note that the seat heaters and and the headlights have a very minimal effect on range. Even cabin heat doesn't have a huge effect.

Will take a look at that website, could be a useful tool - thanks

1. Headlights use almost no energy
2. Heated seats use almost no energy, while the heating does. So you would have been better off turning off the HVAC and turning on heated seats
3. What did the trip meter predict?

I have 17.5k miles on my S already, and I've taken many SpC'ed trips. So far, I've never had range anxiety. In the summer my buffer for SpC to SpC is around 7%. In the winter or rain or wind, I go all the way up to 10%. I trust the trip meter blindly, I don't calculate how many miles it is SpC to SpC and a buffer. 100 miles going uphill will use a lot more range than 100 miles going straight.

I don't think 10% was enough buffer for this trip; we started with 220 miles and only covered around 140miles, arriving with 14 miles range left. That's around 35% range lost!

IMO next time, don't divert out of your way to go to a different Supercharger (unless this one wasn't really that far out of the way). If you wanted more of a buffer than you felt the car was giving you, you probably would have saved a lot of time just going a few mph below what the car recommended for a little bit. Referring to the trip graph is very useful in this situation.

We didn't have to divert, both SC's were en route it's just we were aiming for the farthest one in order to minimise charging time and get enough range to continue our journey to the next SC. As it happened, we stopped at the earlier one and the one we originally planned for!

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.

I live near(ish) High Wycombe, there's Ecotricity chargers just down the road at Beaconsfield M40 Services, there's also a Supercharger at Oxford (Wheatley) Services on the M40. From there you could get up to Warrington SC (Park Royal Hotel) or Keele (using the service road mentioned below), that should then get you home with around 30 mins at each SC?

If you ask Tesla (or join the Tesla UK Owners Group on Facebook) they will give you the access code to use the service road at Keele where you can cross from the Northbound to Southbound sides. It's pretty easy (but you have to pay attention because the satnav will never route you that way - it doesn't know that the service road can be used).

Good tip, thanks!

In these circumstances draft any larger vehicle you can -- trucks, SUVs, minivans. You would be amazed how much range it adds and you don't have to follow that close to get the benefit. If you drafted you probably would have finished your trip with 40 miles of range left. I did this on my trip cross country whenever the range warning came on.

We did experiment with that, but the amount of spray and turbulence being kicked up by the lorries had no positive effect on the wH/mil reading.

Boring!
twice we arrived home or at the charger with... 0 km of range. To convert, it is 0 miles!
last saturday, we arrived home with 4% left...
but, yes, it can be scary...

Have you ever gone beyonf 0%/0km range? Is there a reserve? That can't be good for battery life!!

 

[smsprague]

Got stuck in high winds and crazy traffic on I10 last summer near Palm Springs. Thought I had plenty of range just made it. I saw at least 2 ICE cars on the side of the road that looked like they where out of gas!

 

[Mike_C]

2 miles, wow!! :scared:

 

[smsprague]

My wife almost lost it! A lot of I told you so.

 

[Max*]

I don't think 10% was enough buffer for this trip; we started with 220 miles and only covered around 140miles, arriving with 14 miles range left. That's around 35% range lost!

You didn't use the trip tab. I didn't say 7%-10% buffer for rated miles to real mile conversion. I said 7%-10% buffer from the trip tab.

Like I said going 100miles uphill is very different than going 100 miles straight. So unless you know the terrain, etc. you it's hard to guesstimate (without either using the trip tab, or evtripplanner) what your rated miles to real miles conversion will be.

 

[Mike_C]

You didn't use the trip tab. I didn't say 7%-10% buffer for rated miles to real mile conversion. I said 7%-10% buffer from the trip tab.

Like I said going 100miles uphill is very different than going 100 miles straight. So unless you know the terrain, etc. you it's hard to guesstimate (without either using the trip tab, or evtripplanner) what your rated miles to real miles conversion will be.

What do you mean by the trip tray? The 220 miles was the 'typical' (not rated?) mileage showing in the bottom left corner of the dash. We were then using the energy graph on the 17" screen (and the smaller version on the dash) to monitor wH/mile usage over the 5/15/30 mile trips. Are you talking about this, or another trip menu/screen somewhere?

 

[Max*]

What do you mean by the trip tray? The 220 miles was the 'typical' (not rated?) mileage showing in the bottom left corner of the dash. We were then using the energy graph on the 17" screen (and the smaller version on the dash) to monitor wH/mile usage over the 5/15/30 mile trips. Are you talking about this, or another trip menu/screen somewhere?

Bottom left corner is rated or ideal miles. NOT typical. Your projected miles (based on your last 5/15/30 miles) can be seen from the energy graph, but you can't get that on the IC.

In the energy app, after you navigate somewhere, you can click on the "trip" button at the top (click energy app, then trip), it'll show you a graph from your start point to your end point and how much charge you'll arrive with. It accounts for elevation changes, etc. and it's VERY accurate.

 

[hiroshiy]

Hi, Mike,

My 2 cents.

Cold or inclement weather: add at least 30% buffer, and reduce your speed below 60mph or 100kph
Strong headwind and range problem = drafting

Very simple. Try them and they work! No adjusting of headlights or heats necessary.

 

[Max*]

What do you mean by the trip tray? The 220 miles was the 'typical' (not rated?) mileage showing in the bottom left corner of the dash. We were then using the energy graph on the 17" screen (and the smaller version on the dash) to monitor wH/mile usage over the 5/15/30 mile trips. Are you talking about this, or another trip menu/screen somewhere?

Here's a few screenshots

The gray line is the original prediction. The green/yellow/red lines are your usage.

 

[jerry33]

In almost all cases, if you charge till the trip tab line is all green, you'll have no problems.

 

[Mike_C]

Bottom left corner is rated or ideal miles. NOT typical. Your projected miles (based on your last 5/15/30 miles) can be seen from the energy graph, but you can't get that on the IC.

In the energy app, after you navigate somewhere, you can click on the "trip" button at the top (click energy app, then trip), it'll show you a graph from your start point to your end point and how much charge you'll arrive with. It accounts for elevation changes, etc. and it's VERY accurate.

Aah, I know the one you mean now! Yes we were using that too, although only once we were moving rather than charging. Does this take into account outside temperature too? The only thing I imagine it cannot really account for is a strong headwind...

In almost all cases, if you charge till the trip tab line is all green, you'll have no problems.

Yeah, we didn't check that until we were on the move!

 

[Max*]

It does not take into account a headwind. And there is speculation it takes into account the current temperature, but not the destination temperature.

Once you're driving, if you're watching that graph, it'll show you how close you are to the prediction (gray line). If you're following the gray line, nothing to worry about. If you're above the gray line, even better. If you're below the gray line, slow down or find a closer SpC.

That trip graph is VERY accurate. It's not perfect, but it's REALLY good.

See the all caps letters, that's how good it is

 

[llavalle]

It does not take into account a headwind. And there is speculation it takes into account the current temperature, but not the destination temperature.

Temperature definitely impacts it. Not sure which temp but it does not increased energy usage for a common trip I take almost every week. Below freezing, it will predict around 40%SOC left at arrival. During the summer, over 50%. (from 90%)

 

[Mike_C]

Thanks guys, all good tips to take onboard!

 

[VirtualM]

Thanks guys, all good tips to take onboard!

I think your main problem was the headwind. If you get 10 mph headwind it's like driving with 10mph more speed, and if you follow the energy meter wh/m you will see a drastic increase in energy consumption.
I found this great page for your tesla browser: http://matesla.ca/headwind.html?unit=imperial
You can get easily your total speed.

 

[Jool]

Sorry to hear about your experience! Those headwinds are a serious range killer. I've found that lowering my speed has the biggest impact extending range. Turning off the cabin heater helps a lot too! I wouldn't bother with turning off things like the center display or seat heaters, those don't use much energy in my experience.

 

[smsprague]

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.

 

[Soolim]

Here's a few screenshots

The gray line is the original prediction. The green/yellow/red lines are your usage.

View attachment 113568
View attachment 113569

When and how could the remaining % energy be negative?

 

[studiojon]

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.