Speed Limits and EV’s


Following on from my last entry where I discussed going reasonably slowly, i.e. sticking to the speed limits, I suggested that “the car maketh the driver”. This principle has held true for the 23 cars (and 3 bikes) I have owned and for a great many more people who I have known as well. The idea is that despite perhaps our belief or intuition, that it is our own temperament and experience that determines how we drive, I contend that this is heavily modified by what we sit behind the wheel of.

For example a considerate driver of a Honda Jazz is likely to put their foot down and be a little (or a lot) less considerate in a Porsche 911 Turbo. Never has this been more clear to me than in my Nissan Leaf EV, but in reverse.

In this car everything is designed to psychologically encourage low energy driving. The amount of miles remaining takes centre-stage on the dash, a game where you grow trees depending on how much energy you save as you drive is on the dash for all to see (in fact your statistics are uploaded and compared with other Leaf/ENV2000 drivers around the world) and the car’s cruise control can be activated from 23 mph and is often used, as it accelerates and manages your speed much more smoothly and therefore saves more energy than manual throttle control.

As such I am more likely to drive at the speed limits than in any other car I have ever owned. Precisely at the speed limits by using the cruise control. I do account for the speedometer 10% inaccuracy by setting my cruise control at 33 mph in a 30 zone for example, so my actual speed is 30mph. In every other car I have ever driven I have either been fairly indifferent to the speed limits, often in cars/on bikes which can easily and quickly exceed it or have been driving slower vehicles where it is an effort to get up to speed and therefore quite an achievement to exceed the speed limits.

Over the years I have been flashed by many cameras, but never received a ticket and I have never been on the famed “speed awareness course”. Perhaps I should go, or perhaps I should continue to drive the Leaf which actively and cleverly encourages the saving of energy by psychologically inspiring careful driving.

It is odd that it works this way, because I should drive the Leaf like a boy racer (I’ve got the alloys!) It is fast, it accelerates rapidly and has a totally flat torque curve, the cost of running it is very low, so you can go fast cheaply, and the wear and tear on the mechanical/electrical parts is very low even if you have a heavy left foot. But oddly I don’t, the game isn’t to get there as quickly as possible, but to get there with as many miles of range still available as possible, a totally different sport.

What about the effect on other drivers. Well it seems that two things predominate. The effect of actually going at the speed limit and the effect of using cruise control.

When you actually drive at the speed limit it is more often the case (I’d say around 50% of the time during peak periods) that someone will end up driving up your ar*e. Its a running joke that they will always be driving an Audi or BMW but in all seriousness, confirmation bias means you notice this quite a lot. In almost every other car I’d just go at the speed everyone else is going but in the Leaf I feel more inclined to dig my heels in and make a statement that the speed limit is enough. In fact during my drive to work if I am overtaken by someone, I nearly always come to stop just behind them at the next set of lights, their overtaking manoeuvre got them nowhere. The Leaf discourages harsh breaking and accelerating, and whilst on a racetrack there are only two acceptable states of change of speed i.e. accelerating or breaking (no cruising) if you want to set a fast lap time, on the urban/suburban or even busier country roads, gunning it only results in having to break hard at the next junction and is a total waste of fuel and brake pads.

Cruise control is another area where problems arise. Those using it are constantly frustrated by the changing speed of other road users. When on cruise, which in the Leaf is particularly useful, you are always having to nudge it up or down. Driving without cruise we tend to speed up going downhill and slow down going uphill its a natural thing to do. This means cruise control driving and manual throttling are always going to be odd with one another. This has led some manufacturers to fit adaptive cruise systems that use radar or other sensing technologies to keep you a set distance from the car in front, even auto braking if they slam on the anchors.

Whether this gentle driving effect of regular EV’s also extends to high performance EV’s such as the Tesla Model S I am unable to say until I get my Model S (Tesla if you’re reading I am still waiting). But I suspect it might be a little more tempting to go fast, given the higher performance and the considerably greater range.

Nearly One Year On…..


So the Leaf and I have been motoring for nearly a year and its taken until now to have a “moment”. By moment I mean a “oh bugger I am going to be stranded halfway to work”- moment.

So what happened? Well I am working today (Wednesday) when I normally don’t. Why is this a problem? Because the car has a charging timer which is set to charge in the early hours of the morning on each of the 4 days I am normally at work. However I don’t normally work on Wednesday so it didn’t charge this morning. Typically I arrive home in the evening with around 18 miles range showing on the dash and plug in leaving the charger and its timer to do the work.

This morning, when I started it up and saw 18 miles remaining on the dash, I should have reattached the fast charger in my garage and decided that I had time for a piece of toast and a cup of tea. The 10 minutes extra charge would give me plenty of headroom to get to work (work is 17 miles, so 10 minutes charge at 16A probably gives about an extra 6-7 miles).

However since I was tired and still a bit sleepy I did not notice until I got to Bristol ring road. Shite! Okay I said to myself lets just stop at the rapid charger at Longwell Green Leisure Centre where there is also a McDonalds, and have 10 minutes on the rapid (£4 so not great value for a third of a charge but probably still cheaper than petrol) while I eat a Sausage McMuffin and drink a coffee. But no the rapid charger was dead, the screen showed a blue screen of death. I normally don’t use rapids, my journey to work and back is comfortably within the range of the car even if its only charged to 80% to help keep the battery going. When its necessary to use one, its normally desperate for a charge and when the charger is out of order the frustration is immense. Not only do you not get the power you need but you might have made a detour and used even more to get to the charger, so today I began to sympathise with the public charger woes of some of my EV driving forum buddies.

Okay then I said, steeling my resolve, I was going to drive to work on the charge remaining. According to the guess-o-meter (GOM) I had 17 miles available and 15 miles to drive. I turned off all the electrical gadgets, radio, heaters, lights etc… I even unplugged my phone charger which I was using as a sat nav, (which is laughable as my phone could be charged by the battery in the car probably 100 times even if the car had only 1% remaining), I prayed for dry weather so I did not have to use the wipers.

The problem with the GOM is that it bases it’s assumption of how far you can go on the current battery charge, the current battery usage and the speed you doing averaged over what seems to be about 15-20 seconds or so. So as you speed up or go uphill the range decreases, but obviously slowing down and going downhill increases the range. My route to work across north east Somerset is hilly. This means that I was constantly comparing the sat nav reading of how many miles to get to work, with the GOM estimate of how many miles I could go. At points, such as uphill sections or faster sections the GOM value reduced and at one point was within 1.5 miles of the actual range available. Imagine being in a petrol car estimating 8 miles range with a 6.5 mile journey ahead. (as an aside this is one thing EV’s do well, the estimate of range is normally pretty accurate when you average it out over a journey, the range estimate on a fossil fuel car is often out by quite a lot).

Normally this would induce considerable anxiety; the dreaded and much talked about “range-anxiety” but I have the Leafspy app on my phone which can show you exact battery % remaining, i.e. raw data not a processed estimate. As such I could see the battery had 13% charge when it was telling me I could only drive 7 miles, this really means I had about 12 miles real range before the car stopped completely which is quite a lot less worrying. I knew from Robert Llewellyn’s youtube video that even when the GOM shows 0 miles the car does not stop in fact he drove on 5-6 more miles before grinding to a stop.

So I drove like a (insert politically incorrect example of typically slow driver) sticking rigidly to the speed limits and only going 40 in 60mph zones etc… Whilst this annoys fossil fuel car drivers especially (but not always) those in Audi’s and BMW’s, it was not unusual behaviour today as I often drive precisely on the speed limits using my cruise control, as it reduces battery consumption. I always proclaim that “the car maketh the driver” and not the other way around, this is clearly demonstrated when even committed petrol-head-boy-racers drive their new EV gently to save energy. I was just much more strict about it today, and resisted every opportunity to give it some welly like I normally would just to surprise fossil fuel drivers by how lively the Leaf actually is.

To cut a long story short I arrived at work with 5 miles remaining so had in fact outdone the estimate of the GOM by driving exceptionally conservatively, I plugged in the car and came inside to blog about it.

So after 11 months I have only had one near miss with running out of power and this was my fault for not charging the car, I have lost no battery capacity, my car has only cost £20 in electricity per month to run and it has been a pleasure to drive. In fact a friend asked me if I had taken my motorcycle to work this year, as the weather has been very nice, and I said no. I normally would on the basis that its fun, cheaper than driving a car and I often get there more quickly but this year I have had almost no desire to do so. Its been far too much of a pleasure to drive the Leaf to work every day.