All cars 2 CA

Electric cars comparison : BMW i8 v Holden Volt v Mitsubishi Outlander PHEV v Nissan Leaf v Toyota Prius

For the first time in the history of the automobile, we are entering an era of increasingly mainstream propulsion beyond the traditional internal combustion engine (ICE). Choose petrol or diesel, or gas or an ethanol blend, leave the engine unassisted or put a turbocharger or supercharger on it – these have been your options for as long as anyone reading this has been alive.

Not only do we now have electricity playing a part in propelling humans and the steel and rubber framework around them, but manufacturers are competing in different ways to largely achieve the same goal: emissions free, and perhaps driver-free motoring, without compromise.

So how are we getting there? Best, of course, to start with where we’ve been and where we are now.

For the first time we have rounded up five very different cars that all use electricity in some way (and by the time our testing had finished, another two had launched locally – the Tesla Model S and BMW i3).

It makes sense that the cheapest car here is the one with the simplest form of hybrid technology. Indeed the $33,990 Toyota Prius is renowned worldwide for pioneering the mix of petrol engine with an electric motor to reduce fuel consumption.

Whatever you think of the Prius, there is no doubt it works. It is as simple as combining a 73kW 1.8-litre petrol engine with a 100kW electric motor, though thanks to the way each produce their outputs don’t expect an exact 173kW for the performance equivalent of a Volkswagen Golf GTI (in fact 0-100km/h comes up in a claimed 10.4 seconds, about 4.0sec off that hot-hatch).

The current Prius uses an older nickel-metal hydride battery system, which is now cheaper, and the batteries are so tiny that it can’t actually allow the electric motor to power the Toyota at anything other than low speeds and on light throttle.

Think of it more as taking the load off the petrol engine, which shuts down when cruising or in traffic. Every time you brake, the cells get recharged by harnessing otherwise lost braking energy. Toyota claims the Prius will drink 3.9 litres per 100 kilometres in combined conditions – and for our test, that will be the perfect baseline with which to compare the other hybrids.

The next-cheapest contender is actually the only all-electric model here, the Nissan Leaf. It’s on-sale at the time of writing for $39,990 driveaway, which is perhaps reflective of its limitations.

The reason manufacturers still use hybrids, combining an ICE with an electric motor, is because an ICE can go far and the current battery technology required to power an electric motor either can’t, or is prohibitively expensive (see Tesla).

The Leaf has a mighty electric motor, a big 280Nm unit that trumps even the $300,000 i8 for torque. But because the electric motor produces that grunt, think of it as the 6.0-litre V8 engine of electric cars – it is hungry for fuel. You therefore need lots of batteries to keep it primed, in this case a 24 kiloWatt hour (kWh) battery pack that is about four times larger than that in the i8.

But your household powerpoint can only funnel so much energy into the battery pack, and when there are plenty of batteries, it takes only the simplest of math to work out that it’s going to take a while to refuel.

In short, about eight hours charge gets you 140km of motoring. But remember, when that range is done, you’re done; you’ll need a powerpoint for another eight hours.

Enter the $47,490 Mitsubishi Outlander PHEV and $59,990 Holden Volt, both arriving at the point where things start to get interesting because each go a different way to achieving similar results.

Before we go into that, though, compared with the Leaf the Outlander PHEV has a battery pack that is half the size (12kWh) while the Volt manages a pack that totals 16.5kWh. Mitsubishi claims a charging time of five hours, while Holden reckons four to six is about right depending on 10amp (standard powerpoint) or industrial 15amp connection.

In the PHEV the batteries feed two electric motors – a 60kW/127Nm one driving the front axle, and a 60kW/195Nm one spinning the rears.

And where most hybrids or electric vehicles rob you of boot space to fit in the batteries and electric motor, the Outlander as an all-wheel-drive SUV is able to fit it all under the back luggage floor. You just lose sixth and seventh seating, not boot space. It’s brilliant (as long as you aren't looking for a plug-in hybrid people-mover).

On the downside, the Mitsubishi weighs 1810kg, and because it’s so heavy those electric motors need support from a 2.0-litre four-cylinder petrol engine from the base sub-$30K Outlander. That is a fairly ordinary engine making 87kW and 186Nm, but it actually drives the front wheels when you’re powering away.

The Holden Volt, by contrast, pretty much never uses its 1.4-litre four-cylinder petrol engine to power its front wheels. Nor does it have an electric motor powering the rear wheels like the Outlander.

Simply, it has one electric motor, a 111kW/370Nm unit that out-powers even the electric-only Leaf.

Combined with a kerb weight of 1721kg that is 89kg lighter than the Outlander, in addition to a bigger battery pack, and it will come as no surprise that its 87km of electric only range is well ahead of the 52km of the Mitsubishi.

The difference is, the Volt petrol engine is only there to kick in independently of your throttle and speed, and therefore it could be revving hard when you’re cruising because it acts merely as a generator to refill the batteries that power the electric motor.

It is like a dedicated electric car with a petrol backpack on, where the Outlander is like an extended version of the Prius, with electricity and petrol engine combining to move you along unless you’re fully charged.

Holden claims combined fuel consumption of 1.2L/100km, versus 1.9L/100km for the Mitsubishi – but in either case, those figures are only achievable in the first 100 kilometres when you have a battery pack fully charged, as the more the petrol engine needs to fill in for the depleted batteries, the more fuel you will use across the total 500-600km driving range claimed for both cars.

It’s a big step to the $300,000 BMW i8 supercar.

BMW has seemingly done everything to maximise the abilities of an electric motor-driven car and minimise the usual effects that limit performance and economy. There is slippery aerodynamics that results in a stunning 0.26cD figure (most cars are beyond 0.29), and lightweight carbonfibre construction that results in a 1485kg kerb weight (236kg less than a Volt!).

With drag through the air and weight issues arrowed in on and addressed, the i8 on its bespoke chassis can thrive.

Enter the 1.5-litre turbocharged three-cylinder petrol engine producing 170kW/370Nm, teamed with an electric motor making 96kW/250Nm, all in a four-seat coupe lighter than an automatic Subaru WRX and slipperier than pretty much anything.

The result is 0-100km/h in a claimed 4.4 seconds (about half that of a Volt) and fuel consumption of 2.1L/100km.

Given the 5.2kWh battery pack is about three times smaller than the Holden’s, though, you might think electric-only range would be three times less. Instead of 29km range, though, the much lighter BMW gives you 37km of electric driving. Lightness pays off in total consumption, too, because clearly when the three-cylinder turbo is working on the combined cycle, it is more effortless than the non-turbo fours in the Outlander and Volt that have to work harder to push a heavier car.

So we’ve absorbed the facts and you’ve watched the video – now for the results. For consistency, we left our private test track where we sorted their driving behaviours, and embarked on different efficiency legs.

The Leaf’s claimed 140km was in light cruising mode found to be 132km in real terms – close.

The i8 in similar conditions used 4.5 litres of premium unleaded over a 100 kilometre cruise from outside of Sydney to the CBD; but great braking regeneration also recharged the cells enough for 11km of electric only driving by the time we got there.

Logistics issues meant that we couldn’t align the Leaf and i8 to exactly the same freeway loop as the Prius, Volt and Outlander, all of which completed a 100km lap of Sydney’s ring roads.

The Toyota, as the classic baseline, used 3.8L/100km. After 37km the Outlander PHEV’s batteries were depleted, and it kicked in its petrol engine to use 3.9L/100km overall – worse even than the Prius.

The Volt put its bigger batteries to good use, eking out a brilliant 79km of electric driving range in the same conditions as the Mitsubishi, for just 0.7L/100km of premium unleaded used.

What we should say, though, is that on our private track testing at lower speeds the Leaf claimed 157km of driving range at the start, while the Volt seemed to hover around the 52km mark and the Outlander barely budged from its 37km figure.

The i8, clearly when you’re using its performance as we did, at one point showed 15L/100km…

Unless you really need SUV space and a fifth seat, it’s clear the Holden Volt is the better option than the Mitsubishi Outlander PHEV.

It’s also clear that in this test the Toyota Prius remains brilliantly frugal even on the freeway limit for its size and price, or enough to make you reconsider whether the similarly sized Nissan Leaf is really worth the fuel saving given its range limitations.

And while the BMW i8 may be out of financial reach for the majority, at least it proves 'green' cars can be exciting.

All our electrified cars here have their flaws but they are the proof of how car manufacturers continue to work on automotive solutions that reduce our dependency on oil. If government's such as Australia's could be similarly progressive and offer greater incentives and better recharging infrastructures, electric vehicles may actually have a chance of being not just mainstream but sold in significant numbers.

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