Model 3 (not so!) Long range

[browellm]

Tests have been done on driving faster stop times etc and if driving faster leads to more stops then on some journeys slower could be faster but on your premise of driving faster so needing the same number of stops but having to stop a bit longer I believe faster still comes out faster based on the supercharger network. I have no citation. there are you tube videos out there if you look but generally it turns out faster is still faster. enough to make it worthwhile? that's down to the individual

The central premise of my post is, quote: "you'll get where you're going at least as quickly as you would at 75."

I stand by it. Especially given the real-world charging times and behaviour the OP has quoted. Does he want to make multiple stops after leaving the office at midnight, arriving with <10% SoC to save 90 seconds on journey time? Doubtful.

I don't think Bjorn Nylands efforts to min/max the hell out of something, interesting though are, are that relevant here.

 

[Jason71]

The central premise of my post is, quote: "you'll get where you're going at least as quickly as you would at 75."

I stand by it. Especially given the real-world charging times and behaviour the OP has quoted. Does he want to make multiple stops after leaving the office at midnight, arriving with <10% SoC to save 90 seconds on journey time? Doubtful.

I don't think Bjorn Nylands efforts to min/max the hell out of something, interesting though are, are that relevant here.

You have gone and done it haven't you you have made me do maths and I hate maths!
Maths says Hi and also that you are wrong.
On a 300 mile journey without stopping 75 vs 70 is 17minutes faster. but we all know you can't do that at 70 or 75.
Maths says the faster speed (worst case) will probably require between 8-12 kwh extra energy
Assuming you have to stop once as in the OPs scenario when you arrive at the supercharger your battery will be at a lower state of charge so the extra energy will be replenished at a high speed since that is how it works so for the sake of argument lets say 150Kw. That's 2.5 kw per minute. So That means the extra energy you need for the journey to arrive at the same state of charge will take between 3 to 5 minutes to replenish. so the 17 minute saving drops to 12-14 minutes.
You can tweak my numbers on supercharger speed and energy use but its probably not going to overcome a 17 minute deficit even on a paired V2, which in the ops late night scenario is unlikely

So you can argue all day long about whether driving faster gives a worthwhile saving, though you will have to do it with someone else since I don't have a dog in that fight.

And there may be some scenarios where 75 means a second stop and 70 does not and the chargers are slow etc etc where it could tilt the other way
BUT
as a general rule and specifically in the ops case you will not get where you are going faster driving at 70 than 75 even taking into account charging

Maths out

 

[GRiLLA]

Based on the discrepancy I was getting from real world driving and the range displayed in the car...I charged for 40 mins to prevent another stop on the journey.

Could you tell me what you used to get that journey data? Looks handy

It's a service called TeslaFi, I pay a small monthly fee and it collects all sorts of data from my car, I'm a data geek and proud.

 

[PSmigg]

Yes apologies to all - I was being a bit of a pedant when the statement was made that it is at least as quick going slower. I think the wording of it triggered my inner pedant as it was very black and white. As I implied, there's a myriad of other factors which could mean going at 70 means a quicker travel overall but in its simplest form going quicker is quickest.

 

[Roy W.]

Could you tell me what you used to get that journey data? Looks handy

Other logging services are available - see TeslaMate.

On the charging/not charging issue, at Superchargers I inevitably find the car is ready before I am. I’ll still be sipping my latte and the car is charged. And then there’s the issue of bladder capacity...

 

[exlatccatsa]

You can experiment with different speeds, weights, weather conditions with an app called A Better Route Planner (ABRP) its free in its basic form and it will accurately predict the fastest way between 2 points ( excepting traffic) if you input the correct weights, weather and road conditions. I think this will probably prove that its possible to get there earlier using a slightly slower speed and one less charging stop.

 

[Mrklaw]

and ignoring things like charging.

Its perfectly feasible to get there quicker by driving slower when you take charging and charging speeds into account. If you drive slower, you don't use as much energy, and so charging will not take as long and you can keep charging more in the sweet spot, or even better, you may not even need to charge.

But its also perfectly feasible to drive really fast, and make more charge stops or shorter duration and get there faster too. But I'm not convinced of the practicalities of that on UK roads.

It should be possible to plot a curve of energy usage/range vs speed. And also a curve of charging from low SoC to high. Based on those, woudl it be possible to calculate a crossover point where its the same to drive vs charge.

Eg
- drive at 50mph although more efficient, the speed you're driving gets you there slower than if you'd driven faster and stopped to charge on the way
- drive at 65mph you get there at the same speed whether you run the battery down or stop and charge on the way - it works out the same
- drive at 80mph you use energy more quickly and will have to stop, and the overall journey time will be longer than if you'd dropped the speed a bit.

I think about 60mph is probably a sweet spot for many longer trips, and if you can whack active cruise on at maybe 65 that'll be a good balance of efficient vs not taking too long to get there.

 

[Mrklaw]

Does that mean you set off with 100% and stopped at a Supercharger with 0% having driven 200 miles down a motorway or are those figures extrapolated?

extrapolated. I set off on a 186 mile round trip with a stop halfway. Mostly motorway. estimated 200miles but that would have been to 0. In theory it has a bit more in the tank after that but I'm unlikely to go much below 10% without having a reliable charger in close proximity.

I'd have preferred 200 miles motorway cruising from 100-10% and will bear that in mind for my next car. Pretty much there for now but not in cold weather. And supercharging is faster than I'd expected - literally walking to the toiliet and back is 10 minutes and you're almost ready to go

 

[GRiLLA]

You have gone and done it haven't you you have made me do maths and I hate maths!
Maths says Hi and also that you are wrong.
On a 300 mile journey without stopping 75 vs 70 is 17minutes faster. but we all know you can't do that at 70 or 75.
Maths says the faster speed (worst case) will probably require between 8-12 kwh extra energy
Assuming you have to stop once as in the OPs scenario when you arrive at the supercharger your battery will be at a lower state of charge so the extra energy will be replenished at a high speed since that is how it works so for the sake of argument lets say 150Kw. That's 2.5 kw per minute. So That means the extra energy you need for the journey to arrive at the same state of charge will take between 3 to 5 minutes to replenish. so the 17 minute saving drops to 12-14 minutes.
You can tweak my numbers on supercharger speed and energy use but its probably not going to overcome a 17 minute deficit even on a paired V2, which in the ops late night scenario is unlikely

So you can argue all day long about whether driving faster gives a worthwhile saving, though you will have to do it with someone else since I don't have a dog in that fight.

And there may be some scenarios where 75 means a second stop and 70 does not and the chargers are slow etc etc where it could tilt the other way
BUT
as a general rule and specifically in the ops case you will not get where you are going faster driving at 70 than 75 even taking into account charging

Maths out

Yup, Maths doesn't lie. It's been worked out before, the most efficient strategy in idealised scenarios is to drive as fast as you can (safely and legally!), charging is so quick. Now that relies on you finding a charger at a convenient location, ideally once you get to a really low charge so you can get the fastest charge speed. In the real world that may well not happen, using something like abetterrouteplanner.com will do a pretty good job of factoring in the real world stuff.

In this case it's unlikely that driving 300 miles on a charge is going to work, unless you end up driving far below the speed limit. Yes his range per KWH will increase, unlikely to get him home quicker if there is SuC on the route. Should only need to charge for a few mins, no need to 'fill the tank'. Just stick in your destination and let the car tell you where to charge, and when charging it'll tell you when you have enough to leave.

 

[Adopado]

extrapolated. I set off on a 186 mile round trip with a stop halfway. Mostly motorway. estimated 200miles but that would have been to 0. In theory it has a bit more in the tank after that but I'm unlikely to go much below 10% without having a reliable charger in close proximity.

I'd have preferred 200 miles motorway cruising from 100-10% and will bear that in mind for my next car. Pretty much there for now but not in cold weather. And supercharging is faster than I'd expected - literally walking to the toiliet and back is 10 minutes and you're almost ready to go

I think this is the point. People who have no prior ev experience read our posts about range and wrongly presume that they will therefore be able to routinely drive down the motorway on a 200+ mile journey without charging in an SR+. In some respects we (I’ve done it too) raise false expectations in new owners. I was delighted to note recently that my extrapolated range was 300 miles in my SR+ but maybe my post should have come with a “health warning”! (Definitely no motorway involved!)

 

[Alistairuk]

I think this is the point. People who have no prior ev experience read our posts about range and wrongly presume that they will therefore be able to routinely drive down the motorway on a 200+ mile journey without charging in an SR+. In some respects we (I’ve done it too) raise false expectations in new owners. I was delighted to note recently that my extrapolated range was 300 miles in my SR+ but maybe my post should have come with a “health warning”! (Definitely no motorway involved!)

A lot of what you say is down to the expectations of coming from ICE vehicles to electric without fully understanding some of the current "limitations" that exist due to external factors (availability of chargers at the optimum location for you)!

If you're used to driving down the motorway until your fuel light comes on, happy in the knowledge that when it does you just pull in at the next services/town to refuel, when you switch to EV you find that you can't do that - especially if you're using the Tesla network as unless purely by a lot of luck and the chance you happen to be coasting up to a supercharger as you hit 10% you're going to feel a bit cheated / mislead by the whole "I can easily do 200+ miles".

I feel the situation will improve over the coming years as obviously more and more service stations will start providing reliable EV charging points at similar speeds to what the Tesla network does and I can only hope that we'll see more and more petrol stations - especially in more rural areas - start to provide rapid EV charging - perhaps the government could consider grants / loans towards the costs of installing rapid chargers at independent petrol stations which I'm sure will encourage the faster spread of them (look at what Transport Scotland has managed in Scotland with their grant schemes for public charge points).

Once we start to see reliable rapid EV chargers appearing at all petrol stations then you'll be able to realistically say that you can do 200+ miles without charging in an SR+ (which yes, you can do now, but probably not in reality unless you know your destination has a charger!).

I will champion the Tesla navigation system (although I'm sure one day it will screw me over) and its predictions, although I would like it to offer the option of setting a desired destination arrival charge so that it then routes you to an appropriate supercharger on route if you're going to arrive below that wanted charge level!

 

[GRiLLA]

Here's four examples of a motorway journey of roughly 300 miles in a LR M3. ABRP understand charging curves and consumption, also factors in the time to get to the charger and plug in and out. The total time taken is always faster if the car is driven faster, even in the 90 mph scenario where you need to stop twice.

BTW of course I'm not recommending anyone drives above the speed limit, while the maths of charging works, the maths of injury and risk definitely shows that faster is more deadly.

 

[GT_M3]

Yup, Maths doesn't lie. It's been worked out before, the most efficient strategy in idealised scenarios is to drive as fast as you can (safely and legally!), charging is so quick. Now that relies on you finding a charger at a convenient location, ideally once you get to a really low charge so you can get the fastest charge speed. In the real world that may well not happen, using something like abetterrouteplanner.com will do a pretty good job of factoring in the real world stuff.

In this case it's unlikely that driving 300 miles on a charge is going to work, unless you end up driving far below the speed limit. Yes his range per KWH will increase, unlikely to get him home quicker if there is SuC on the route. Should only need to charge for a few mins, no need to 'fill the tank'. Just stick in your destination and let the car tell you where to charge, and when charging it'll tell you when you have enough to leave.

Trying different scenarios on ABRP for a long journey I did in the past showed me that a faster 2-stop strategy (e.g. 100% ref speed, 5h 11m; 110% 4h 58m) was overall quicker than a slower 1-stop strategy (90%, 5h 30m; 80% 5h 59m). Luckily the superchargers were pretty much en-route. While there is no way of knowing what the speed on the road will actually be like on the day, my general takeaway was the higher the average speed, the shorted the time even allowing for an additional stop. I'm not advocating driving over the speed limit, but driving purposely slowly to save a stop didn't pay off in my scenario.

My concern now is that with the popularity of the M3 there could be a queue to supercharge, waiting an extra 30 mins to get in to a stall could wipe out any time gained by driving quickly.

 

[mswlogo]

What tire pressure is OP running. A Few pounds makes a huge difference. Also what tires makes a big difference.

I drive 65-70mph and get better than EPA on Model 3 AWD (19” OEM) and Model X (20” OEM).

 

[GT_M3]

Here's four examples of a motorway journey of roughly 300 miles in a LR M3. ABRP understand charging curves and consumption, also factors in the time to get to the charger and plug in and out. The total time taken is always faster if the car is driven faster, even in the 90 mph scenario where you need to stop twice.

BTW of course I'm not recommending anyone drives above the speed limit, while the maths of charging works, the maths of injury and risk definitely shows that faster is more deadly.

View attachment 674766

you beat me to it. exactly this.

 

[Jason71]

Here's four examples of a motorway journey of roughly 300 miles in a LR M3. ABRP understand charging curves and consumption, also factors in the time to get to the charger and plug in and out. The total time taken is always faster if the car is driven faster, even in the 90 mph scenario where you need to stop twice.

BTW of course I'm not recommending anyone drives above the speed limit, while the maths of charging works, the maths of injury and risk definitely shows that faster is more deadly.

View attachment 674766

Good example.
What you have also shown nicely is the law of diminishing returns on speeding up.
60 to 70 saves 42 minutes,
70 to 80 25mintutes
80 to 90 only 11 minutes
E is proportional V squared. You can't fight maths and physics will also give you a good kicking given half a chance

 

[Jason71]

My concern now is that with the popularity of the M3 there could be a queue to supercharge, waiting an extra 30 mins to get in to a stall could wipe out any time gained by driving quickly.

This.
I'm going to Cornwall on the first Saturday of the summer holidays.
I'll let you know

 

[GRiLLA]

Good example.
What you have also shown nicely is the law of diminishing returns on speeding up.
60 to 70 saves 42 minutes,
70 to 80 25mintutes
80 to 90 only 11 minutes
E is proportional V squared. You can't fight maths and physics will also give you a good kicking given half a chance

Yup, actually as you get past 120mph the total time does start increasing again, but that's of little relevance.

 

[ACarneiro]

With my driving style, I plan for 200 miles on a full charge.

 

[15Peter20]

Anyone notice/believe the horrendous Wh/mile numbers seen during the first few miles of any journey? Regardless of battery temp, air temp etc I almost always get 400Wh/mi showing for the first five miles or so, which then rapidly converges with a more nominal 250 Wh/mi or so.
I expected (and got) this in winter, but even after an 80 mile journey on a warm summer evening, if I interrupt it with, say, a 10 minute Supercharger visit I see these horrendous initial numbers after leaving the charger.