Hybrid vs plug-in hybrid vs mild hybrid vs electric vehicle: what’s the difference?

What is a hybrid car?

A hybrid is a catch-all phrase that in automotive circles is used to describe a vehicle that combines two power sources.

While there are rare exceptions, the most common combination is a petrol engine and one or more electric motors. But how those two power sources interact can vary enormously between brands and models. Most run a parallel hybrid system, whereby the engine and motor operate in tandem to drive the wheels.

Depending on the state of charge in the battery pack and the driving conditions, the car may utilise the motor or engine more - or call for maximum power from both concurrently. The electric motor can also often be used to drive short distances or under light loads.

In the past, some brands have referred to them as self-charging hybrids. But regulators in some countries have cracked down on that definition as being misleading because it suggests the car can charge itself without any external help.

The reality is a hybrid runs purely on petrol but utilises some of the energy created by the petrol to charge its battery pack.

Another type of hybrid is called a series hybrid, such as that used in the Nissan e-Power models. In a series hybrid, the engine is used purely as a generator to create electricity, which is then fed to a battery pack to power one or more electric motors.

As with all hybrids and EVs, regenerative braking - which captures energy normally lost when decelerating - chimes in to charge the battery. The better regular hybrid systems - as they’re sometimes referred to - can reduce fuel use by around half, with the biggest benefits in stop-start suburban driving that can utilise the advantages of regenerative braking.

Advantages of hybrid cars
The better hybrids can halve fuel use; relatively affordable technology; proven and well accepted.

Disadvantages of hybrid cars
Run purely on petrol and cannot be externally charged; no option to run on electricity alone.

Who should consider a hybrid car?
Drivers looking to halve their around-town fuel bills for a modest price premium.

Popular hybrids for sale in Australia
Toyota RAV4, Toyota Corolla / Corolla Cross, Toyota Camry, GWM Haval H6

The BYD Sealion 6 is the Chinese brand's first plug-in petrol hybrid vehicle to launch in Australia.

What is a mild hybrid car?

A mild hybrid car provides some modest fuel saving benefits. The technology is broadly the same as what you get on a more traditional hybrid, but with some key differences.

Firstly, the generator or motor often won’t be used to power the car. Instead, it’ll allow the engine to shut down sooner and store energy captured through mild regenerative braking in a battery pack.

That battery then powers the ancillaries such as lights, ventilation and audio. By allowing the engine to shut down sooner while decelerating or when stopped it can save precious drops of fuel, in turn lowering emissions.

However, just to confuse the situation, some mild hybrids can also use their electric motors to provide very mild assistance when accelerating.

You often won’t even feel it because the assistance is minimal, so the car drives like a regular petrol-powered model. But your fuel bills may reduce slightly - by maybe a few per cent - predominantly in city driving.

Some brands refuse to refer to them as mild hybrids. The most prominent is Toyota, which recently introduced a mild hybrid in some versions of the Hilux ute. Instead referring to the tech as “V-Active”, it uses a 48V electric motor (most EVs run 400V or 800V systems). It’s claimed to reduce suburban fuel use by as much as 10 per cent (the lack of braking on a freeway means the benefits are less at higher speeds).

The beauty of mild hybrid systems is that they’re a relatively affordable way to get incremental efficiency gains. The electric motors and batteries tend to be small and typically integrate easily with existing engines and transmissions, rather than requiring major engineering work.

Note: Sales of mild hybrids aren’t reported as sales of hybrid vehicles.

Advantages of mild hybrids
Simple way to incrementally reduce fuel use; relatively affordable and easy to integrate into existing drivetrains.

Disadvantages of mild hybrids
Minimal fuel saving benefits, especially on a freeway; adds complexity and another thing to go wrong down the track.

Who should consider a mild hybrid car?
Anyone wanting the driving experience of a petrol car but with marginally lower fuel bills.

Popular mild hybrid cars for sale in Australia
Toyota HiLux

What is an electric vehicle?

An electric vehicle (EV) is exactly that: a vehicle that runs purely on electricity, including solar power.

But because there are different types of EVs - including hydrogen-powered fuel cells, none of which is on sale in Australia yet - the more common battery-powered ones are often referred to as battery electric vehicles, or BEVs.

A BEV uses one or more electric motors and gets its energy from electricity supplied from a battery pack that is charged externally.

It’s relatively simple technology from the drivetrain perspective, but the requirement for a large battery pack adds significant cost to manufacturing. Batteries are high tech, complex components that can cost tens of thousands of dollars.

Obviously, charging an electric car takes longer than it does to refuel a petrol or diesel car. The fastest charging EVs can add about 300km of driving range in about 15 minutes, but slower home charging typically requires an overnight top-up. And while public charging infrastructure is improving, there’s progress required to make long distance driving in an EV as effortless as it is in petrol and diesel cars.

Still, there are big running cost benefits if you can charge an EV at home, especially if you have solar (even better with a home battery system).

The entry price of electric cars is also falling, with many EVs available for less than $40,000. Novated leasing an EV can also potentially save thousands in Fringe Benefits Tax, while some states and territories offer discounts and rebates for purchasing an electric car.

From an Aftersales perspective, EVs typically have much longer service intervals than a petrol or diesel vehicle, as well as lower servicing costs, while the performance benefits, driving experience and unique features of an EV are a drawcard for many.

Advantages of electric cars
Performance and driveability; potential to significantly lower running costs; reduced servicing requirements; ease of home charging.

Disadvantages of electric cars
Often more expensive than petrol alternatives; public charging challenges.

Who should consider an EV?
Drivers with easy access to home charging (preferably solar); families running two cars who can limit one to driving near home; drivers travelling less than 500km a day, motorists considering a novated lease.

Popular EVs for sale in Australia
Tesla Model Y, Tesla Model 3, BYD Atto 3, MG4, BYD Dolphin, GWM Ora

The BYD Dolphin is one of the cheapest and smallest electric cars available to buy in Australia. 

Which type of hybrid car is best: hybrid or plug-in hybrid?

The car powertrain technology that has really taken off recently is the oldest of the lot: regular hybrids.

It’s easy to see why hybrid cars are popular. With a price premium over an equivalent petrol model of as little as $1500, the reduction in fuel use - up to 50 per cent - can quickly pay that off.

Mild hybrids are a nice-to-have but because the fuel saving benefits aren’t as great as regular hybrids they’re often not worth spending more on.

Plug-in hybrids make most sense for those who need to travel big distances - think upwards of 500km a day - ideally in areas not well serviced by public charging infrastructure or not ready to go fully electric.

However, to maximise the benefits of a PHEV you really need easy access to electric car home charging - and you need to plug in the car regularly.

Which type of electric car is best: PHEV or EV?

In short, an EV typically offers better performance, better efficiency and a better driving experience. But the long answer as to which is best for you comes down to how and where you plan to use it.

EVs are terrific for zipping around town and for staying within a few hundred kilometres of home base. They’re a great way to lower running costs (such as by downsizing a car), avoid petrol stations for good (especially if you have solar) and enjoy a superior driving experience with excellent throttle response and acceleration.

Venturing further than that with an electric car requires some planning and understanding of the public charging network, which is constantly expanding but sometimes caught short during busy periods, such as long weekends.

However, EVs can easily tackle long drives along popular regional routes, especially up the east coast of Australia.

PHEVs can work well for predominantly shorter daily trips, as long as you’re fastidious with plugging in to charge. And PHEVs give that freedom of being able to take off without having to worry about charging.