FAQ: Electric vehicles

During the early years of the 20th Century, the race was on to see which one of three competing drive systems would power cars over the next hundred years. Internal combustion won out against steam and electricity.

Steam fell by the wayside early, but electricity never quite went away. Electric vehicles (EVs) remained in production – often as commercial vehicles for short-range/short-duration use – right throughout the period when combustion was king.

Now, in a different climate (Ed: see what Ken did there), electricity has emerged as the proposed new wunderkind of automotive power.

And here are the reasons why... As well as the arguments to the contrary…

Why are electrically-powered vehicles back in fashion?
Ever since the oil crisis of 1973, car manufacturers have been acutely aware of the limitations imposed on them by fossil fuels. It became evident the oil industry was supplying a finite resource – prompting concerns about 'peak oil' production and energy security. It's literally true that wars have been fought to secure energy reserves.

But the real problem with internal-combustion technology has only come to light in recent years. Engines which emit carbon dioxide – an unavoidable result of a machine burning hydrocarbons to produce power – are contributing to production of a greenhouse gas. On a global scale, the millions of cars in use every day are collectively discharging CO2 at such a rate that some climate scientists anticipate at least a two-degree increase in average annual global temperatures by 2050.

EVs don't burn hydrocarbons. They don't emit CO2 (or toxic nitrogen oxides either). And they're quieter and more efficient for urban driving conditions.

So how does an electric motor work?
Picture a water wheel. Paddles attached all around the wheel are pushed by water flowing downstream. The energy of the water is converted to rotational energy (torque) because the paddles are attached to the wheel, which is, in turn attached to an axle which is allowed to rotate freely.

Now, picture that same water wheel with a team of firefighters standing alongside it, on the downstream side. They train their fire hoses at the paddles at the top of the wheel and the concentrated jets of water apply energy to those paddles. The water wheel is now turning in response to water currents from two different directions and at different points in each revolution.

Imagine now that the paddles are coils of conductive metal, like copper. And instead of being pushed by water flow, they're being pulled or drawn by magnetic force. That is the basic operating principle of an electric motor. The water wheel is the 'armature', the axle is the 'rotor' and the water streams are magnetic fields from two magnets of different polarity.

As the armature turns, an electric current running through each coil creates an electromagnetic field that draws the coil towards one of the fixed magnets in what is referred to as the 'stator', the fixed outer shell of the motor. As the coil approaches the point closest to the North-pole magnet, the current running through the coil is interrupted and a segmented collar around the rotor reverses the polarity of the current running through the coil. This segmented collar is the 'commutator'. It reverses the flow of electrons from the battery, thus reversing the polarity of the electromagnetic field generated by the coil.

The coil is now drawn to the South-pole magnet (the fire hoses) on the other side of the stator rather than halting at the North-pole magnet (the river). Inertia and the commutator's timing of polarity changes keep the armature spinning in the same direction, rather than stopping and reversing direction.

There are no moving parts other than the armature, and the electric motor is more efficient than an internal-combustion engine because it produces torque from very low speeds. It's so simple to build, any half handy person could build one in a backyard shed, using copper wiring, magnets, a sufficiently powerful battery, a case, ball bearings and a shaft.

If the technology is simple, why are EVs so expensive?
Although the initial upfront cost can seem high, electric vehicles promise lower running and maintenance costs – so total cost of ownership may result in price parity with vehicles powered by internal combustion engines.

That initial 'sticker shock' boils down to the cost of batteries. To store the necessary power for performance and range, the EV's battery pack has to be 'energy-dense' and compact. The best battery technology to date for EV application is the lithium-ion battery. This is basically the same sort of battery which powers your laptop or mobile phone, but, for cars, the battery has to be scaled.

As companies gear up to develop and produce these batteries (and companies dig up more lithium), the cost will reduce. Indeed, EVs and plug-in hybrids, using the same type of battery, are increasingly affordable.

The holy grail of battery development is one which is lighter, more compact – for its energy storage capacity – and cheaper to produce. No one knows when this will be, but teams all over the world are working towards the goal, and futurists are predicting the big breakthrough will occur within a decade.

Currently the purchase price of an EV remains high – the Nissan LEAF currently costs double the price of a similarly packaged small car – so buyers are clearly 'early adopters' rather than practically-minded consumers. When prices of EVs achieve parity with conventional (internal-combustion) cars, the rationale for choosing a conventional car will get compromised.

That said, there are cost advantages to buying a high-end EV, like the Tesla Model S.

Cost advantages? Like what?
EVs are subject to a higher threshold for Luxury Car Tax, avoid stamp duty in the ACT and (for example) receive a $100 registration discount in Victoria. The newly formed EV Council is working with the Federal Government for further tax concessions to support EV purchases.

How far can I drive an EV on a single battery charge?
Range is a function of battery and vehicle efficiency. All Tesla models for instance are NEDC-rated to travel over 400km and up to 632km between battery recharges. Other EVs won't travel as far, but BMW claims its i3 94Ah will conservatively manage 200km before needing to recharge. The new Nissan LEAF claims an NEDC range of 400km.

How long do EV batteries last and do they degrade like a phone battery?
We asked Tesla for information on this. It explained the make-up of the Panasonic 18650 cell used in in its Model S and Model X is different to other technologies, such as mobile phones or laptops. Tesla provides an eight-year/unlimited-kilometre warranty on the battery, and it claims customers from all corners of the globe have reported very little, if any, degradation throughout their EV ownership.

What does it cost you to run?
For all their high-tech images, EVs cost less to run than most people expect. Putting home solar to the side for a moment, the cost of off-peak electricity is considerably cheaper than petrol, and servicing an EV should cost less than an internal-combustion car, because there are fewer moving parts and fewer related components (cooling, for example) requiring attention.

Home charging varies depending on the plan, however AGL currently offers a $1 per day plan for unlimited kilometres. Supercharging is 0.35c per kilowatt, however it's free if an owner referral code is used when purchasing a Tesla. Destination Charging is a free service offered by most of the landlords that have installed the chargers.

How long does it take to recharge?
Earlier EVs like the Mitsubishi i-MiEV would deplete battery charge within a couple of days commuting from home to work and back. The range was nominally up to 160km, but in reality the vehicle would be lucky to travel half that distance at night and in the rain, when the battery was also supplying power for lights, wipers and heating/demisting. Things are improving, with Tesla's Model S leading the way.

Recharging times, using a standard (10-Amp) power outlet at home will typically keep plug-in hybrids off the road for up to four hours. If the battery is fully depleted, a Tesla Model S essentially requires the best part of a whole day to recharge fully by this method.

Car companies are now supplying 15-Amp and three-phase power converters for installation at home to reduce the time spent waiting for recharging. Some of these 'wallboxes' can recharge even a high-performance/long-range EV to 80 per cent of capacity within 20 minutes.

Tesla offers three major types of charging. Home charging (overnight) is most common (90 per cent of charging), allowing for a full charge every morning if needed. Supercharging is for long distance travel (30 mins for a half charge, which is enough to get you to the next Supercharger or destination). And Destination Charging allows for top ups during a stay at a resort or hotel, during a meal at a restaurant or while visiting a shopping centre.

The common analogue to the EV is the mobile phone. You plug it in at night and have the equivalent of a full tank of petrol the next morning.

So I don't need to rewire my home/solar to charge my car?
This is one of the myths… No rewiring should be required for any Australian home which has been built to code and maintained properly.

Tesla’s own wall connector can be set to deliver 16-Amp, 24-Amp or 32-Amp, or the owner can charge at 10-Amp, so there should be no impact on the home set-up unless the owner wishes to upgrade to three-phase or higher-amperage single phase.

Three-phase power can speed up the recharging process and is, in Tesla’s case, available with its Wall Connector. Solar is certainly a good option for the environment (and the household budget) if you can charge during the day.

Nissan is pioneering 50 and 100kW chargers in Japan. These are not intended for normal home usage. Instead the Japanese company is developing floor mounted contactless charging.

Why are there different charging plugs. Will this be standardised?
Most car companies marketing EVs provide the standard 10-Amp plug used in Australia as a minimum. Tesla uses the European standard Mennekes Type 2 connector, which is the most reliable for the power supply being undertaken to charge Tesla vehicles.

What do I do if I run out of electricity?
Most EVs are incorporating a trip planner into their monitoring – both onboard and via apps. Tesla’s trip planner incorporates two warnings based on the process. Should both be ignored and the owner continues driving, 24-hour roadside assistance is available.

What's actually involved in servicing EVs?
Electric motors are far simpler than an internal combustion engine. With the motor and drivetrain employing less than 17 moving parts (in the case of a Tesla), there is far less to go wrong.

Servicing is typically recommended annually for safety and diagnostics checks. Brake fluid changes and battery coolant fluid also need changing eventually.

How does driving an EV help the environment when electricity in Australia is 'dirty'?
At this stage EVs frequently draw power from environmentally unfriendly sources, such as coal-fired power stations. But there is a move away from coal among energy wholesalers in Australia.

Victoria's Hazelwood power station has been decommissioned and AGL is committed to closing its Liddell power station in New South Wales within the next few years.

South Australia is migrating to renewable energy, with help from Tesla; plus the cost of renewable-energy technology is rapidly falling and is cheaper than building new coal-fired power stations.

AGL's '$1 per day' plan mentioned previously is fully carbon offset. In addition, the move towards cleaning up the grid is an easier option over time .

But the manufacturing process for EVs is currently worse for the environment than conventional vehicles. EVs depend on expensive, lightweight materials which are energy hogs in production. But once the car is on the road, it quickly offsets the added burden on the environment. Toyota claims its Prius hybrid offsets the CO2 produced during production within 20,000km of driving.

Nissan's LEAF was deemed to be one of the cars on the market to boast "the smallest life-cycle environmental footprint of any model year 2014 automobile available in the North American market (with minimum four-person occupancy)," according to America's Automotive Science Group.

Can an EV tow my boat/caravan/trailer?
While the inherent torque of the electric motor makes EVs potentially an effective tow vehicle, only the Model X is known to be capable of factory-endorsed towing, at this time.

What happens when there’s water over the road?
Car companies are well aware of the old truism that electricity and water don't mix, so they're very careful to ensure that their EV's electrical components are properly isolated from the elements.

Some years ago, Land Rover developed an electric Defender which would wade through a water crossing with the same competence as an internal-combustion model. Modern EVs come with batteries completely encased, and with safety mechanisms in place to disconnect supply should an impact occur.

Will I enjoy driving an EV?
Setting aside cost and the environment for a moment, the advantage of EVs is they're so easy to drive, and relatively comfortable. There are no gear changes, no noise from combusting fuel pushing against pistons, no drivetrain whine.

Tesla owners are particularly vocal about their cars… Just ask one… They argue the case that the Model S (for example) in its highest specification, provides more performance, relative to its purchase price, than conventional cars costing double the money.

Additionally, EVs often drive well, because the battery pack can take any form and the weight of it can be distributed evenly throughout the car.