When I turn on my Tesla ‘Autopilot’, the car sits squarely in the middle of the lane, much more accurately than if I were driving it myself.
It occurred to me to wonder, as more people use these devices, what that might do to the wear and compression of the road surface?
Of course, cars aren’t all the same width, but they don’t differ too much, so perhaps over time we’ll end up running in little tracks; a kind of guided busway, where it’ll be harder to drift accidentally out of your lane even in the absence of electronic assistance.
Or perhaps car manufacturers will be required to introduce a a little randomised ‘drift’ into their algorithms to stop the roads having to be repaired so often?
As the world moves rapidly in the direction of electric propulsion, there is one big challenge, irrelevant to the majority of car-buyers but a serious concern for a significant subset of us: what are these EVs like when used for towing?
This has been more in my mind recently as we have just purchased a small boat — more on that later, once we’ve finished sanding and varnishing! But when you add up the people who tow caravans, horses, motorbikes, classic cars, trailer-tents, ride-on lawn-mowers etc, there’s quite a population for whom this is a real issue.
I haven’t yet done much towing, but one of the key factors that made us choose the Tesla Model 3 at our last car-change was the fact that it could take both a roof-rack and a tow bar; something that, at the time, was really quite rare on EVs.
There are, of course, two key questions most people want to ask: how much can a given EV tow, and how far can it tow it?
How much?
EVs ought, in general, to have very good towing capacities because of their enormous torque, and the fact that they’re quite heavy. (Experts suggest that, in general, it’s best only to tow things up to 85% of the car’s weight, and the EV batteries give you a bit more leeway!) EVs also, of course, lack things like a clutch and gearbox, components which, in days gone by, tended to suffer a bit from towing.
But towing hasn’t, thus far, been a priority for most EV manufacturers, which means that these powerful, heavy cars are often not actually built with it in mind, and so are not rated to tow loads as substantial as one might expect. (There are also probably challenges in getting things like the regenerative braking right for both braked and unbraked trailers.) My Model 3, for example, weighs quite a bit more than a VW Golf and has infinitely more power, yet its rated towing capacity of 1000kg seems a bit weedy compared to the Golf’s 1500kg or so. The Model Y, just starting to make its way to these shores, has a more respectable 1600kg rating, and the Hyundai Ioniq 5, which has been getting a lot of positive reviews recently, has the same.
An enterprising campsite owner, Chris Scott, has put together a useful list showing the towing capacities of most current EVs. While none of those available at present in the UK will compete with a Land Rover, there are nonetheless quite a few to choose from if you want to tow most normal loads, and if you have the (rather significant) budget for a Tesla Model X, you can pull a similarly significant weight!
How far?
Yes, as always, this is the elephant in the trailer.
Here’s a quick rule of thumb when you hang something on your tow bar: take the real-world range of an EV, and halve it. That, of course, is a wild generalisation, but it’s often quoted, and tied in with my first experience towing a trailer on the Model 3.
“What?!”, you say. “You’ve been trying to tell me that EVs are good when they can only do 300 miles compared to my car’s 400! And now you stick a poxy little trailer on the back and tell me it’ll only do 150?” This number doesn’t phase me; before the Tesla I was driving an EV which had a range of about 70 miles without a trailer, and we went all over the country in it. But yes, that’s right. You’ll probably have to stop every two or three hours. But you should really do this for safety whenever you’re driving, and just how big is your bladder anyway?
The thing is that EVs are often very dependent on their aerodynamics for their range, especially Teslas, which are normally exceedingly slippery. Spoil the airflow with a big roofbox or a chunky trailer and it will have a very significant impact.
But here’s the important thing: this is nothing to do with the power source. If you had the same car with the same aerodynamics but with a petrol engine, the drag would still change to the same degree and the effect on the range would be similarly drastic. You just don’t think about it as much with traditional cars: in EVs, it’s typically higher up in your consciousness. Few people really check the range of their petrol car when towing for several hours on the motorway.
Having said all of that, my experience in towing our little boat from her former home in Dorset to Cambridge, 165 miles away, was quite encouraging. First, it towed beautifully; the gear-less acceleration and single-pedal driving made for a very nice experience. And secondly, the loss of range, though significant, wasn’t as bad as I’d feared.
Tesla likes to use measure consumption in watt-hours per mile (analogous to the European litres-per-100km), so bigger numbers mean more energy used. By setting the cruise control to 60mph — the maximum towing speed in the UK — my average consumption was 400 Wh/mile, compared to my normal 285 Wh/mile or so — and, because it was fairly late at night, I was able to maintain that speed most of the way home. If I’d had to go slower, the consumption would have been lower.
Or, to use the miles-per-gallon analogy adopted by most other manufacturers, I went from about 3.5 miles/kWh to about 2.5 miles/kWh. A big difference, yes, but much better than half. That would give me a real range of around 180 miles. If I had started the three-and-a-half-hour journey with a full battery, I could have made it home without having to stop for a charge. And this was night-time in February, with the associated winter inefficiencies of lower battery temperatures, headlights, and needing to keep the driver cozy and warm while he listened to his audiobooks…
The real issue
For those of us who remember the pioneering early days of EVs — i.e. just a few years ago — today’s charging stations can be a source of wonder. If you manage to park a modern car with a nearly empty battery at a new super-rapid charger, then the rate at which you top up can be astonishing.
Once again, Tesla owners are a bit spoiled here: my old BMW would charge at a maximum rate of 50kW, rapidly dropping off as it filled up its little battery. That meant that the peak rate got you about 3 miles for every minute you spent charging, and you had plenty of time to take the dog for a stroll or even have a quick meal before driving for the next hour.
The newer Tesla superchargers can manage up to 250kW, if your battery is warm and empty, and because of the size of the battery and some clever management, can maintain a high rate of charge for much longer. Popping to the loo and then picking up a coffee or a quick snack is time enough to add vast amounts of charge before you set off again.
But, in either case, this does take longer than filling up with dinosaur juice, and the result is that most charging stations, at least in the UK, are designed more like a car-park than like a ‘drive-thru’. There are some notable exceptions, like the Electric Forecourt at Braintree, which I visited when it first opened a little over a year ago. If you haven’t seen it, here’s a section from my video at the time:
At most charging stations, though, you’re expected to sit there for a while, so you pull into a parking space. And, in the case of Teslas, the charging sockets are all at the back, so you’re expected to reverse into that parking space in order to connect the very short, very high-power cable.
This is clearly not ideal if you’re towing. For a light trailer like my boat, it’s the work of a moment to unhitch it and put it in a nearby parking space, but it would be more challenging with a bigger load.
So can I make two appeals?
The first is to the installers of charging stations — you lovely people — to consider including one or two stations suitable for people with caravans attached? And to put a sign asking those who don’t need them to make use of the other ones first?
And the second is to the creators of charging-point maps, to include data about whether a charging station is trailer-friendly, and to allow searching on that basis. It would be fabulous to be able to plot your course across the country, stopping to charge only at places where you didn’t need to unhitch.
In the meantime, occasionally you can find charming and quiet charging points, like this one near Winchester, where there’s plenty of space for eccentric parking arrangements!
If I were giving advice to somebody considering buying a Tesla at the moment, it would be (a) buy it and (b) don’t believe the ‘full self-driving’ hype… yet.
You’ll be getting a car that is great fun to drive, has amazing range, a splendid safety record, a brilliant charging network, etc… and, in the standard included ‘autopilot’, has a really good cruise control and lane-keeping facility. One thing I’ve noticed when comparing it to the smart cruise control on my previous car, for example, is that it’s much better at handling the situation where somebody overtakes and then pulls into the lane just in front of you. Systems that are primarily concerned with keeping your distance from the car in front have difficult decisions to make at that point: how much and how suddenly should they back off to maintain the preferred gap. The Tesla, in contrast, is constantly tracking all the vehicles around you, and has therefore been following that car and its speed relative to yours for some time, so can react much more smoothly.
The dubiously-named ‘Full Self-Driving’ package is an expensive optional extra which you can buy at the time of purchase or add on later with a couple of clicks in the app. At the moment, it doesn’t give you very much more: the extra functionality (especially outside the US) hasn’t been worth the money. If you purchase it now, you’re primarily buying into the promise of what it will offer in the future, and the hope that this will provide you with significant benefits in the time between now and when you sell the car!
But at sometime in the not-too-distant future, the new version –currently known as the ‘FSD Beta’ — will be released more widely to the general public. ‘Full Self Driving’ will then still be a misnomer, but will be quite a bit closer to the truth. YouTube is awash with videos of the FSD Beta doing some amazing things: people with a 45-minute California commute essentially being driven door-to-door, for example, while just resting their hands lightly on the steering wheel… and also with a few examples of it doing some pretty scary things. It seems clear, though, that it’s improving very fast, and will be genuinely valuable on highways, especially American highways, before too long, but also that it’s likely to be useless on the typical British country road or high street for a very long time!
What Tesla has, to a much greater degree than other companies, is the ability to gather data from its existing vehicles out on the road in order to improve the training of its neural nets. The more cars there are running the software, the better it should become. But the back-at-base process of training the machine learning models on vast amounts of video data (to produce the parameters which are then sent out to all the cars) is computationally very expensive, and the speed of an organisation’s innovation, and how fast it can distribute the results to the world, depends significantly on how fast it can do this.
Last week, Tesla held their ‘AI Day’, where Elon Musk got up on stage and, in his usual way, mumbled a few disjointed sentences. Did nobody ever tell the man that it’s worth actually preparing before you get up on a stage, especially the world stage?
However, between these slightly embarrassing moments are some amazing talks by the Tesla team, going into enormous detail about how they architect their neural nets, the challenges of the driving task, the incredible chips they are building and rolling out to build what may be the fastest ML-training installation in the world, and the systems they’re building around all this new stuff.
For most people, this will be too much technical detail and will make little sense. For those with a smattering of knowledge about machine learning, you can sit back and enjoy the ride. There are lots of pictures and video clips amidst the details! And for those with a deeper interest in AI/ML systems, I would say this is well-worth watching.
There are two key things that struck me during the talks.
First, as my friend Pilgrim pointed out, it’s amazing how open they’re being. Perhaps, he suggested, they can safely assume that the competition is so far behind that they’re not a threat!
Secondly, it suddenly occurred to me — half way through the discussions of petaflop-speed calculations — that I was watching a video from a motor manufacturer! An automobile company! If you’re considering buying a Tesla, this is a part of what you’re buying into, and it’s astonishingly different from anything you’d ever see from any other car-maker. Full self-driving is a very difficult problem. But this kind of thing goes a long way to convincing me that if anybody is going to get there, it will be Tesla.
You may or may not ever pay for the full FSD package, but it’s safe to assume much of the output of these endeavours will be incorporated into other parts of the system. So, at the very least, you should eventually get one hell of a cruise control!
The livestream is here, and the interesting stuff actually starts about 46 minutes in.
When we have proper and affordable self-driving vehicles, will that be the end of the railways?
Clearly there are some things that railways will do better for the foreseeable future, like long-range high-speed links, or carrying heavy freight. And don’t get me wrong: I like train journeys. But it seemed to me that the key reasons people currently take trains for normal day-to-day journeys — wanting to read en route, a lack of parking at their destination, avoiding congestion — could very soon be overcome when, for example, your car can go and valet-park itself after dropping you off at the office.
And the disadvantages of train travel: the fact that instead of going from point A to point B, you have to go at least from point A to point B to point C to point D, possibly waiting on a cold platform at point B for an indeterminate period, and not being sure whether you’ll get a seat from point C to B on the return journey. Will it be worth the hassle?
One of my assumptions is that traffic congestion will become less of an issue when cars are smarter, of course, which may not be a valid one, especially if lots of train travellers take to their cars instead.
There’s an interesting question as to whether lots of small independent agents trying to meet their own goals are going to result in an optimal solution for road congestion as a whole. We may start off with vehicles that are pretty autonomous initially, but become less so in due course, as the road infrastructure starts to adapt to them. Network packets on the internet know their destination, but it’s the routers (the junctions) that tell them which exit from the roundabout to take.
Will the Department of Transport manage overall use of the network better than each individual car? Well, that depends on who has the better computer scientists, of course! But it also depends on the amount of knowledge each vehicle can get about the overall road network, and, of course, on how selfish your car is: will it decide that the needs of the many outweigh the needs of the one (or the few)?
Perhaps we need Altruistic Autonomous Vehicles? (You heard it here first!) There could be financial incentives to encourage this. You get lower road tax if your car agrees to obey centrally-prescribed rules at times of high congestion. Perhaps you get to use the high-speed autonomous-only lanes if you’re willing to hand over to the cloud-based algorithms. Of course, this could open up all sorts of wonderful opportunities for hackers, too. Remember the movie?
Anyway, perhaps congestion will be less of an issue, but for a completely different reason. If you can be having a coffee, working on your laptop and taking Skype calls while you slip quietly along in your electric car, you may be more productive than if you’d got to the office on time.
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I had the honour of meeting Elon Musk briefly some years ago. Back then, he was just doing space exploration. There aren’t very many people for whom you could write that sentence – even without the word ‘just’ – but for him, its inclusion is entirely appropriate.
Now, he seems to be doing… well… everything that’s cool. I have since admired his orbital exploits, ridden in his cars, and, of course, bought a significant proportion of my purchases using Paypal – which helps pay for all the rest.
The latest product is apparently to be batteries – here’s the new press announcement – but these are not your average AAs. They’re wall-mounting.
At 10kWh, these could run a lot of LED lightbulbs for a long time. Especially if you’re not also using them to recharge your model S.
They’re designed to make it easier for solar-equipped households to depend less on the grid, especially by time-shifting the peak sunshine energy at noon to the morning and evening, when there’s peak demand. That’s not simply about being green: just a few weeks ago, visiting friends were telling us about the ‘loadshedding‘ powercuts in Cape Town recently, where everybody got a scheduled two-hour outage each day to help cope with the insufficient power-generation capabilities in the country. This seems perfect for that, too.
Still, the next challenge Musk has to address is the really tricky one: the manufacture of solar panels which don’t ruin the appearance of the building to which they’re attached.
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