Unpleasant Experience nearly running out of charge on M6

[adsheff]

Tebay is at the top of a really long hill! There's your issue. Just switch the display to % - the miles guessing is just misleading.

 

[pdk42]

I’ve driven that same route, in both directions, many times, in both a Roadster (back in 2011-2012..) and a Model S. The Roadster had half the battery capacity and 50% worse Cd, so the energy drain was much more noticeable than in an MS. Before Superchargers there was a UK HPC / High Power Charger network for Roadsters, and Tebay had one!


The most important thing to bear in mind is that the M6 from Gretna to Tebay gently rises just over 1,050 ft / 320m reaching a peak just before J39 / M6 / Shap turn-off .. which also happens to be the highest section of motorway anywhere in the UK!

The extra energy required to haul the M3 up that very long slope, in addition to just normal cruising on the level, can be calculated from bog standard O level maths. At the Shap summit the potential energy the car has gained has to come from somewhere, namely the battery, and the simple equation for PE = Mass X Elevation-change X Gravity-constant. So, to haul a 2,000kg car up a gradual 330m high slope, and allowing for a mere 15% loss due to inefficiencies, requires approx 7.5mj of energy, or approx 2kWh beyond the normal energy for driving economically on the flat. That 2kWh equates to about 8-10 miles loss of range if driving 50mph. A modest head wind of just 10mph over 40+ miles will also cost the best part of 2kWh as well, so call it approx 4kWh total, and this helps explain 15-20 mile loss of range beyond normal eco cruising at 50mph.

Obviously there are many other factors that could be considered, but hope this helps provide an explanation.


Here's a gratuitous photo taken at Tebay, from about 9 yrs ago, showing the forerunner to Superchargers !

View attachment 574675


View attachment 574676

Was that an AC charger ? What sort of charge rate did you get?

 

[Plagued]

I thought the navigation system did take into account elevation, or is that just ABR? Generally my % at arrival figure is absolutely bang on.

 

[Adopado]

No I wasn't. As I had gone beyond the point of no return (Gretna Services) I was accepting my fate at this stage and to be honest it never even occurred to me to look at the energy graph.

Ah right. If the car does not know where it's going then it is unable to provide an accurate prediction of consumption. This is a route with very significant gradient changes yet the predictions you were getting were based on the default "ideal" driving conditions. You absolutely have to set the destination and use the energy graph (or use ABRP) to get a reasonably accurate prediction. Battery calibration may be an element but I don't believe that was the main culprit. If your S experiences were over more moderate terrain then maybe you could "get away with" just following the miles remaining.

 

[Adopado]

I thought the navigation system did take into account elevation, or is that just ABR? Generally my % at arrival figure is absolutely bang on.

OP wasn't using the navigation system ... that was the mistake!

 

[TheManofMead]

Lots of you have mentioned about monitoring the expected % on arrival. This is part of the problem that occurred, having thought about it further. In navigation on the Model S the miles reamining, time to go AND % on arrival are constantly shown. This is what I do pay close attention to on trips in the S. I noticed during the trip that the M3P navigation display does NOT show arrival percentage. Bit irritating I thought and so this contributed to the problem and it diverted my reliance more to just the "miles remaining" statistic.

 

[TheManofMead]

Ah right. If the car does not know where it's going then it is unable to provide an accurate prediction of consumption. This is a route with very significant gradient changes yet the predictions you were getting were based on the default "ideal" driving conditions. You absolutely have to set the destination and use the energy graph (or use ABRP) to get a reasonably accurate prediction. Battery calibration may be an element but I don't believe that was the main culprit. If your S experiences were over more moderate terrain then maybe you could "get away with" just following the miles remaining.

I was using the navigation. As I mentioned in the opening post, it was nagging me to charge at Gretna...and as I mentioned this was my grave error.

I have checked the altitiude graph this morning on ABRP (see image) showing the journey from Scotland to Tebay services. As you can see the blue dot represents Gretna, and from there there it is pretty much constant uphill for most of the journey, except the very steep downhill for last 2 miles hurrah. Several others have also made this point about the long uphill stretch.

 

[Adopado]

I was using the navigation. As I mentioned in the opening post, it was nagging me to charge at Gretna...and as I mentioned this was my grave error

Sorry, I misunderstood. I thought you hadn't put Tebay as your trip destination in the nav but had just relied on the car estimating range as you drove the route.

 

[exlatccatsa]

This makes good watching if you're getting close to the mark..as I have been..0% does not mean zero miles. I've done about 5miles after searching for (9) chargers that were out of service in a local village and having to go to the next.

.
I was looking at the range leaderboard in TeslaFi. The lowest mileage to get onto the leaders board used to be 269 miles in May. Achievable on a long run. But now I see its up to 300 miles, I don't think thats achievable in Scotland..Perhaps Cardiff to Norfolk?

 

[hingus2000]

I think it’s a shame that the trip consumption graph is hidden away in the menus and to bring it up obscures the navigation.

From a UI perspective it would be nice to be able to see both.

 

[PV4EV]

'Back in my day.....'

Gosh makes all the moaning we hear about SCs now seem rather trivial. Do you still have the Roadster? In a different life without family responsibilities I would truly love to own one!

I sold it a couple of years ago, although I'd miss it for all it taught me about EV's and energy efficiency combined with amazing performance possible from solar .. and I used to get through about £5k-6k worth of petrol in a previous car of (almost) equivalent performance. All that 'guilt free acceleration' meant I could put a number plate which almost reads FREE PWR to emphasize the solar point. Its now on my MS which is just as relevant as the car has free supercharging for life and results in people at SC's take photos of the plate !

My old Roadster actually came up for sale at a Silverstone auction recently, and was even featured on 'Harrys Garage' on youtube. I was sorely tempted to buy it back, but I've got enough garaging problems as it is.


(for those that like 'classic' cars and olde worlde supercar stuff from the past, HarrysGarage videos provide excellent watching. I used to lust after a lot of the cars featured and even owned some, but now I've been EV for a few years I just do not see the point in ever buying an ICE car again. 'cept maybe a Lamborghini ;-)

.

 

[PV4EV]

Thanks for the explanation which helps to explain the miles evaporating. Even better the photos and the insight into those of you who were there in the earliest days of Tesla.

As far as I know, I was one of about 20 UK owners, although most of them seem to wrap them in cottonwool. I actually used mine daily for 4 yrs and never had any problems with hotels etc, allowing me to plug it into a bog standard 13 amp socket.

Whats fascinating about the Roadster is that even though it was developed in 2007/8/9 it had all the DNA for what became the Model S. IE, it had masses of data monitoring of battery cell/pack/module data, primitive touch screen controls for most things, over the air data/car monitoring, TPMS, canbus and OBD port so 3rd party phone apps were also available, and so on. The Model S came along and featured a fully fledged GUI on its huge touchscreen even though the back end was similar to the Roadsters !! Back then the data could monitored via the Roadsters ‘debug mode’ that owners weren’t supposed to look at. Being an engineer type person I loved it. It gave raw numbers that made you at-one with the machine, although my grandmother would not have understood any of it due to a lack of said GUI ;-)

By using the precise and repeatable raw data monitoring, I was able to spend a 3 months doing full time R&D on my Roadster’s aerodynamics / wheels / tyres to enable me to end up with a car that had about 45% more range than the standard ‘rated range’. In the last year of ownership I was driving around in a Roadster that was getting typical usable mileages of about 260-270 miles (instead of the 180 it would previously get), and on an extreme run up a motorway at a steady state, 300+ miles was possible due me managing to get the energy use down to around 170 wh/mile ! Total capital cost of mods was around £500, although you could buy the bigger battery for a mere £29,000 to get the same result. If you bought the bigger battery and added my aero mods, you'd be looking at a Roadster with around 450 miles max range in ideal conditions, which is probably way more than anyone needs.

Examples of the debug data and refined energy usage are shown below. There were 11 mods to the bodywork including some really neat tricks around the underside wheel arch areas to get that extended range, but the biggest impactor was simply putting a smooth transparent piece of perspex across the unnecessary air-intake (if it did need to turn on the fans for cooling, it could still pull air in via side vents).

The Roadster had 3 modes, Performance, normal, and range mode. When it got to 0% in normal mode it actually meant you had about 20 secret miles left, if you took it easy. If you continued to drive it would then get to show ‘-- range unknown’, but even then it would still allow you to drive another couple of miles, followed by a ‘car will shut down in 60 seconds’ message and then ‘plug in immediately to avoid critical damage to batteries’ (or similar). The one time I ever saw this was a the end of a long journey and after limping up a the final half mile hill to my house with it in ‘--’ unknown range left mode, and the car did actually shut down just as I rolled over the curb into the parking spot in front of my garage. That was a close call. Lessons like that meant it never happened again !

 

[PV4EV]

Was that an AC charger ? What sort of charge rate did you get?

The HPC's were approx 16kw AC single phase, or 240v/70amps. The Roadster's battery was approx 56kWh max, so it would be a 3 hr wait if you needed a full charge, although I only ever waited an hour or so max, just to complete a journey. 99% of the time I would just leave it plugged into a 13amp mains socket at home. When ecotricity came along in 2013/4 I modified one of my charge cables to be able use their chargers to get 60amps, but that was more because I could, rather than needed to.


Amazingly, Tesla still have the 2011 press release on their website that explains a bit about why Tesla UK were persuaded to install HPC’s up and down the motorway network !

Tesla unveils high power charging network from Lands End to John o’Groats


.

 

[MrBadger]

As far as I know, I was one of about 20 UK owners, although most of them seem to wrap them in cottonwool.

There are at least 3 parked up at Tesla Brooklands/Weybridge service centre in various states of disrepair. Looks like the headlights do not like being kept in the sun.

 

[Gatsojon]

I was using the navigation. As I mentioned in the opening post, it was nagging me to charge at Gretna...and as I mentioned this was my grave error.

I have checked the altitiude graph this morning on ABRP (see image) showing the journey from Scotland to Tebay services. As you can see the blue dot represents Gretna, and from there there it is pretty much constant uphill for most of the journey, except the very steep downhill for last 2 miles hurrah. Several others have also made this point about the long uphill stretch.View attachment 574818

Blimey, you like to live on the edge!

 

[i3m3Andrew]

I noticed during the trip that the M3P navigation display does NOT show arrival percentage. Bit irritating I thought and so this contributed to the problem and it diverted my reliance more to just the "miles remaining" statistic.

The M3 does do this, if you either tap on the style of satnav on the top left of the screen, one of the modes is the entire route which shows the estimated state of charge at the end of the journey or if you did a round trip back to your current point. It will also do this if you drag down on the little tab under the satnav destination to the right of the mapping screen.

 

[TheManofMead]

The M3 does do this, if you either tap on the style of satnav on the top left of the screen, one of the modes is the entire route which shows the estimated state of charge at the end of the journey or if you did a round trip back to your current point. It will also do this if you drag down on the little tab under the satnav destination to the right of the mapping screen.

Exactly. If I drove the M3P day to day I might have known this. Plus it literally being 3 months old and (virtually) never driven. Biggest factor of all of course my own complacency

 

[Jeeves]

I think it’s a shame that the trip consumption graph is hidden away in the menus and to bring it up obscures the navigation.

From a UI perspective it would be nice to be able to see both.

Couldn’t agree more.

 

[pdk42]

I noticed during the trip that the M3P navigation display does NOT show arrival percentage.

It can - but it's shown under the step-by-step routing instructions. You need to pull that down from the panel on the right in the navigation screen.

 

[Neilio]

I was using the navigation. As I mentioned in the opening post, it was nagging me to charge at Gretna...and as I mentioned this was my grave error.

I have checked the altitiude graph this morning on ABRP (see image) showing the journey from Scotland to Tebay services. As you can see the blue dot represents Gretna, and from there there it is pretty much constant uphill for most of the journey, except the very steep downhill for last 2 miles hurrah. Several others have also made this point about the long uphill stretch.View attachment 574818

Forget about charging your car. From the first screenshot I'm really concerned that your phone is going to run out of battery