Ready, Set, Charge!

If you are one of the many who has opted for an EV for whatever reason, then the time will come when you have to charge it up – just like you have to charge up your phone, e-reader or laptop. However, charging an EV is not quite the same as filling up a petrol or diesel tank, and if you’ve never done it before, there are a few things that you’ll have to get used to, especially regarding the different charging speeds.

Deep breath required here. There will be maths.

With all types of charging, the exact amount of time you’ll need to charge the battery will depend on the voltage of the outlet and the battery capacity. The formula for working it out is:

E = P × t

Makes you feel a bit like Einstein, saying that. E is energy, P is power and t is time.  Rearrange this and you get t = E/P or, in plain language:

Your EV’s battery capacity (in kWh) ÷ power output of the charger (in kW) = hours of charging time

This equation, however, mainly applies to charging to 80% rather than 100% (and this is the charge time figure that you’ll see in specs and stats from the manufacturers of EVs). This is because charging isn’t a linear process and it slows down as the battery gets closer to full charge. It’s a mechanism that helps prevent overheating. If you want to charge to 100%, bear in mind that doing so will take a bit longer.

The thing that most people are concerned about is the charging speed. In fact, the charging times are one factor that can put people off purchasing an EV, especially an all-electric BEV or a PHEV. Here in Australia, we have reasonably sensible names for the different charging speeds, unlike in other countries, where you have to ask a few questions to be sure what you’re talking about during a discussion of fast charging – you’ll hear some people talk about fast charging as something different from rapid charging (I feel sorry for those who don’t speak English as their first language because – well, you try explaining the difference between fast and rapid!). Here, we keep things straightforward, calling the two most common charging speeds Level 1 and Level 2, with only the fastest type being called “DC fast charging”.   

Level 1 charging is simplest type of top-up charging that you can do at home or anywhere else you can access a standard common or garden power socket.  It seems very simple but the trouble is that this type of charging is very, very slow. Recharging a completely drained battery will take at least a whole day, as in a 24-hour day.  It could even take 48 hours, which is fine if you’ve got the whole weekend to recharge your car’s batteries as well as your own and don’t have to go anywhere.  On the other hand, if you find yourself at a relative’s place in the country and not enough charge to get you home, you can just plug in and recharge enough to get you home again, or at least to the nearest public charging station (it would be nice if you compensate your relative for the power you’ve used, same as if they let you have a jerrycan of petrol if you’d run out). You may hear this referred to as trickle charging.

Level 2 charging is the sort of charging you do with one of those wall boxes in your home, and Level 2 chargers are what you’ll find in typical public chargers of the kind you’ll see at the supermarket, mall or gym and, if you’re really lucky, at work. Typically, you get around 7.2 km of mileage for every 10 minutes of charging with a 7.2 kW unit, or 22 km of mileage for every 10 minutes with 22 kW charging. (Is anybody else getting flashbacks to the sorts of word problems we had to solve at school?)

However, remember that these mileage figures are approximate and are under ideal conditions. If you have a heavy load, if you have to go into a headwind, or if you want to run the lights or heaters or play music, you’ll reduce the range.

Commercial outlets will often provide chargers not just for their customers’ convenience (although this is certainly part of their motivation) but also as a marketing ploy. If you need to ensure that you’ve got enough charge in your battery to get you home again after work and shopping, then you may need a couple of hours to charge the battery to the right level. However, it may take you only one hour to do your workout at the gym or to pick up your groceries, leaving you with time to kill. Chances are that you’ll spend time in the gym cafeteria or that you’ll spend a bit longer in the supermarket browsing the shelves to fill in the time and will thus spend more money, which is what the commercial outlets are hoping for.  Just be aware of this little ploy and budget for it, develop some iron self-discipline and a healthy bit of patience, or take a book. Just don’t make the mistake of sitting in your car doing things on your phone or laptop with your device plugged into the charger in the car!

Speaking of budgets, a home wallbox will have to be bought separately when you buy a new EV. It’s a good idea to buy one, as otherwise you’ll be relying on super-slow trickle charging or public charging stations to top up the battery. It will also need to be installed by a professional electrician, like your oven or hot water cylinder and for the same reasons. You’ll also have to factor the cost of labour in as well. This is something to keep in mind.

DC fast charging (aka rapid and ultra-rapid charging) uses DC electricity, whereas Levels 1 and 2 use AC electricity. The best known DC chargers are the Tesla superchargers even though, ironically, the original Nikola Tesla promoted and popularized the use of AC electricity. How fast this type of charging will be will depend on the battery, but charging can be done in less than an hour, depending on the kW rating and the type of car. Some EVs charge faster than others. It has to be remembered that not all EVs are compatible with DC fast charging; this is often the case with PHEVs. This is something to check and think about when you buy an EV.

It’s also important to understand the different types of connectors or plugs, but that’s another story for another time.

Opening Windows Versus Air Conditioning

When the weather gets hotter, it’s important to stay cool when you’re driving.  However, these days, it’s important to consider fuel consumption as well and get the most out of what you’ve paid for – and what we’re going to talk about in today’s article applies to electric vehicles as well!

The two best choices for keeping cool inside the car are using the air conditioning system and the old-fashioned method of opening the windows (if you’re over a certain age, you’ll always try to pantomime cranking a handle to indicate opening a car window.). However, you may have heard people tossing around the idea that opening the window is less fuel efficient. Or you’ve heard that using the air conditioning increases fuel consumption. Which of these is true?

It is certainly true that running the air-conditioning puts extra demands on the engine and consumes more energy when it runs (and this is true of internal combustion engines, hybrids and electric vehicles). This means that when you ask the system for some nice icy-cool air to flow through the cabin and keep you fresh rather than hot and bothered, you increase your fuel consumption.

However, opening the windows affects the drag and aerodynamics of your car. When they design them and test them, designers try to get the drag as low as possible, and they study the way that air flows around the vehicle at speed (usually using wind tunnels as well as computer modelling). This is done to reduce the amount of friction affecting the car, because the more friction that needs to be overcome, the more energy will be required, which requires more fuel, etc. etc. All these tests assume that the exterior of the car is rigid. However, when the windows open, all bets are off and the equations go out the window (almost literally). The open window affect the flow of air, which is how opening the windows cools you down, but it also increases turbulence.

The big question is which is worse in terms of fuel efficiency. Sweltering in the heat just isn’t an option – that’s downright dangerous, especially given some of the temperatures reached in some parts of Australia during summer. So what does the fuel-efficiency-minded person do?

The windows versus air conditioning debate has been going on for some time. In fact, the popular TV show Mythbusters had a go at it. They got both guys driving around a track in similar SUVs, one with the windows down and one with the air conditioning on to see which one ran out of fuel first.

The one with the air conditioning did, which looked like that case should be closed, but it’s not as simple as all that. Firstly, the Mythbusters test wasn’t a strictly controlled one. Even two vehicles of the same make and model will perform differently, depending on a range of factors, including the condition of the engine and the inflation of the tyres. Secondly, the two presenters have different builds and probably have different driving styles, simply because they’re different human beings. To be a more rigorous scientific test, the only thing different should have been the choice between air con and windows open. In other words, the test should have been conducted with the same vehicle driven by the same person with exactly the same conditions – which possibly wouldn’t be the case if you only drove the car once with the air con on and windows up, then with the A/C off and the windows down, as the operating temperature of the engine (cold start vs. hot start) also affects the fuel efficiency. Lastly, one test isn’t enough in the world of science – one result could be just a one-off exception. The ideal is to run test after test after test and see what the general tendency is.

It also gets more complex than that. It turns out that the more aerodynamic a vehicle is to start with, the bigger the effect of drag will be. In other words, in a smooth, sleek sedan, the effect of opening the windows will be greater in terms of percentage than opening the windows on a big chunky 4×4.

To cap things off, speed also has an effect. This is because the faster you go, the more air resistance your vehicle encounters, so the drag increases, and they increase exponentially. This means that if you’re driving at 100 km/h, the effects of drag are four times greater than what you experience at 50 km/h.

The problem was put to a team of actual engineers who ran a proper scientifically rigorous test* to solve the problem. They used two vehicles, a 2009 Ford Explorer to represent the big SUVs and a 2009 Toyota Corolla to represent the sedans. They were tested in the lab and on the road at a variety of speeds and at idle. Here’s what they found:

• At 40–70 miles per hour (that’s 64.4–113 km/h), in both vehicles, turning the air conditioning up to the maximum (which is how they ran the tests) used more fuel than opening the windows.
• Above 70 miles per hour (113 km/h), the two cars behaved very differently.
• At 75 mph (121 km/h), in the Toyota Corolla, there was no difference between having the air con on and having the windows down.
• In the Toyota Corolla, at 80 mph and above (that’s 129 km/h – did they test this legally on an actual motorway or did they have their own circuit somewhere?), having the air conditioning on was more fuel efficient than opening the windows.
• In the Ford Explorer, having the windows down continued to be more fuel-efficient than using the air conditioning.

The study also tested the air conditioning at different settings other than full blast, but you have to pay to see those results!

Of course, not all cars are Toyota Corollas and Ford Explorers, and each has its own drag coefficient and intrinsic fuel efficiency. However, a good general rule of thumb is that if you’re travelling around town, windows down is more fuel efficient. In small sporty vehicles, using the air conditioning is best at open road speeds, but having the windows down is more efficient for big chunky ones.

Here, I will have to add that there are some other advantages of using the air conditioning rather than opening the windows. Firstly, if the outside air is already hotter than comfortable, you’ll only feel a small drop in temperature if you open the windows. It might not be enough to drop temperatures of 40° or more to a nice comfortable room temperature of 18°C. However, the air conditioning will really drop the temperature to this ideal level.

The other problem is that it isn’t just air that can get through the window when its open. Having half a swarm of bees going through the window isn’t the best for safe driving. Nor is having a wasp fly through the window a good idea. Worse still are stones flying up. I’m not making this one up. Last summer, when we were towing a caravan with the windows down and had pulled over to let someone pass, a stone flicked up, glanced off the wing mirror and flew through the open rear window and hit my adult daughter in the face.  A freak accident, I know, but I know that from now on, both she and I will be using the air conditioning on the open road.

* Huff, S., West, B., and Thomas, J., “Effects of Air Conditioner Use on Real-World Fuel Economy,” SAE Technical Paper 2013-01-0551, 2013, https://doi.org/10.4271/2013-01-0551.

Filled For Life? The Truth About Automatic Transmissions

“Oh, you don’t have to change the automatic transmission fluid,” he said.  “It’s filled for its lifetime.” He was a university professor (in the field of biomechanics) so I assumed he knew what he was talking about.  However, things didn’t go so smoothly when his automatic transmission tried to change gears later.  Turns out that biomechanics experts aren’t actual mechanics!

The idea of having a fluid in your car that doesn’t ever need to be replaced or topped up sounds great. We should be topping up everything else on a regular basis, from the radiator to the window washing fluid to the oil. Not having to do this for the transmission fluids sounds almost too good to be true.

And you know what they say about things that sound too good to be true…

The trap that a lot of us can easily fall into is the whole idea of the “lifetime” automatic transmission fluid.  What does a lifetime actually mean?  Does it mean forever until the end of the universe (short answer: no)? Does it mean for the rest of your lifetime?  The car’s lifetime? Or something else?

It turns out that the lifetime in question is the planned lifetime of the car. This is not the same as the actual lifetime of the car.  Car manufacturers, who are always coming out with nice new models want you to buy those nice new models. No harm in that and if you want a new car, why shouldn’t you get one? However, some manufacturers have a sneaky way to push you into buying a new car possibly sooner than you want to, known as “built-in obsolescence”. This means that the car manufacturers expect that a vehicle will wear out – and need to be replaced – at some point.  You can get an idea of what the expected lifetime of a car is by looking at the warranty, which is either going to be the age of the car or the mileage. After the car has clocked up that many kms or that many years, you and the manufacturer can expect things to start showing a few signs of wear.

Don’t blame the car manufacturers too much for this. There is nothing that can be done about the law of entropy, and it’s in the nature of things to break down and wear out over time.  You can see evidence of this fact when you look in the mirror (and the biochemist could tell you more about that in great detail). I know my face doesn’t look as smart and new as it did 15 or so years ago.

However, some of us like our cars and we’re rather fond of them. We don’t want to move on something as comfortable and familiar as an old friend. We would like to keep them for longer, thank you. There are those of us who are into classic cars, and there are those who, despite some of the great offers out there, are more likely to get a second-hand car that has passed the threshold of the magical number in the warranty. What happens then?

The fact is that you’re going to have to do something about the fluids in your automatic transmission. That fluid gets old and deteriorates over time, and when it does, then it won’t work as well as it used to… and neither will your automatic transmission. To keep the gears changing the way they should, then it’s time to do something about the fluid.

I don’t want to hear that line again about not changing the automatic transmission fluid because it’s got a lifetime guarantee. Remember those cheap watches that had a “lifetime guarantee”? That “guarantee” that meant that the watch wouldn’t break until it came to the end of its life, and you knew when it came to the end of its life because it would break, i.e., it was guaranteed not to break until it broke.  The same thing applies here. The lifetime is the lifetime of the fluid, so it won’t need to be replaced until it comes to the end of its lifetime – which is shorter than the lifetime of the car, to say nothing of yours.

So what comes next? To flush or not to flush the automatic transmission, that is the question.

There’s a bit of debate about whether one should flush an automatic transmission, or whether it’s better to simply change the fluids. If you’re new to the world of motoring – which we all are at some point – then let’s start by describing the difference between them.

• Changing the fluids means that the old fluids are simply drained out without the help of any special equipment, new fluids are put in, then the filter is replaced and there you go. You can do this yourself. Some of the old fluid will still be left inside the system and will mix with the new fluid.
• Flushing the automatic transmission involves the use of a pump that will ensure that every single bit of the old fluid, along with any junk and debris that’s got caught in it, gets removed from the system and completely new fluids will be added.

You can get a rough idea of this by picturing a bottle of hand sanitiser or similar goop. Changing the fluids is like squeezing or pouring out the contents and putting fresh stuff in (try it; you’ll see bits of the old stuff stuck on the sides). A full flush is like giving it a full scrub out under the tap before putting new stuff in.

Some say that you should only change the fluid, as the forces involved in flushing can move that inevitable debris from the corners and get it into the working parts, which can damage the transmission. This argument has some weight to it, and the risk is real. However, a mechanic who knows what she/he is doing will have the right equipment and will be able to do it properly. Because this can be a bit pricey and it’s something of a deep clean for your car’s transmission, it shouldn’t be done that often. Have a look at the fluid in question. If its still a nice translucent scarlet, a flush isn’t needed. If it’s thick and black, then it’s flushing time.

Merely changing the fluids can be done more frequently – about every 2 years or thereabouts for your average driver. It will need to be done more often (as will a full flush) if you put your automatic gearbox through a workout on a regular basis – lots of towing or lots of very short trips being the main ways to stress the auto gearbox.

How often should you change the fluids in your automatic transmission or get it flushed?  The answer will vary. However, one thing’s for certain: the gearbox is not filled for life and when it comes to automotive maintenance, listen to the person in the blue overalls with black smears, not the person in a white lab coat.

Spot the Difference?

Did you know that the Renault Koleos is very much a Nissan X-Trail?  Were you also aware that the current BMW 7-Series is the platform for the new Rolls-Royce Dawn?  These days car manufacturers are sharing a lot of the components that go into making a new vehicle.  A lot of the electronic systems and computer chips are shared between makes and models, even engines and an entire body platform.  As the costs of designing and building a complex new car rise, by getting together and pooling money, skills, assets, and sharing the costs of the new build, these are definitely clever ways for manufacturers to reduce their overheads, and the overall cost of designing and building a new vehicle.

Platform sharing between manufacturers and between models is, perhaps, more common than you may have thought; and particularly now more than ever.  In some cases, the similarities between a particular car, truck, or ute and its platform-twin are obvious.  However, at other times it’s not so easy to detect the resemblance.

A car’s platform is the base (including body shell, floor, and even some of the chassis and engine parts) on which it is built.  Not only can these components be common to more than one manufacturer, but they can also be shared between models in a manufacturer’s line-up.  The initial platform design and its production or engineering works can be shared across a number of different models.  Kia and Hyundai are some of the best brands at doing this sort of thing, and so too is VW.

Sharing componentry between different manufacturers/brands has to be built on an existing good business relationship.  So, when two or more automotive manufacturers with a good relationship have shared the same desire to save money, they can operate together and agree to share development costs and also essentially sell the same cars but under different badges.  Renault and Nissan are great examples of this.  Some of the most talked about illustrations of this occurring recently will have been the Toyota GT86 and the Subaru BRZ, which are essentially the same cars tarted up slightly differently.  Also, the Toyota Corolla station wagon and the Suzuki Swace (a less known model here in Australia) are exactly the same car.  Another illustration would be the awesome new Toyota Supra and BMW Z4 cars.  Also, Volvo has platformed shared quite frequently over the years.  The Global C-car Platform from Ford saw the Volvo S40 and V40 share much with the Ford Focus and Mazda 3.  Well known Hyundai and Kia have utilized several duplications of platforms for their small automobile line-up since 1997.

Having a shared engineering platform, where manufacturers build a basic foundation that can be used across many of its own models is an advantage.  The Volkswagen Group (VW), and the brands it owns, (Audi, Bentley, Lamborghini, Porsche, Seat and Skoda) are masters of this craft.  VW has a common practice where they will build a smaller number of platforms, but the benefits come when they will then re-purpose these platforms across their own different brands.  When VW designed and built the MQB (Modularer Querbaukasten) platform, it was shared across the Audi A3, Skoda Octavia, and Seat Leon.  Also, one of its SUV platforms is shared and utilized by the Audi Q7 and Q8, the Bentley Bentayga, the Lamborghini Urus, and Porsche’s Cayenne.

BMW’s 7-Series is the platform for the immensely luxurious and expensive Rolls Royce Dawn.  The new 7-Series is luxurious and sleek in its own right, but it is also much, much cheaper to buy – comparatively.

Some other new vehicles that are currently sharing platforms:

Cadillac CTS and Chevrolet Camaro

VW Polo and Skoda Scala

Mercedes Benz GLE and Jeep Grand Cherokee

Renault Koleos and Nissan X-Trail

Fiat 500 X and Jeep Renegade