BEVs, PHEVs, HEVs and MHEVs explained

by Petrol Mum
Volvo XC40 Recharge Pure Electric drivers dash

Australians are purchasing electric and hybrid vehicles in numbers never previously seen, anecdotally though there is still confusion surrounding what under the bonnet of these different EV options. BEVs, PHEVs, HEVs and Mild Hybrids are all explained here with a brief outline about what each term means theoretically and in the real world.   

The Australian Climate Council recently released its Race to Zero Ranking, which rates how quickly car manufacturers in Australia are moving towards electrifying their fleets and mapping out a pathway to sell nothing but zero emissions vehicles by the mid-2030s or earlier. Polestar, Tesla and Volvo are currently the top three companies on the Race to Zero Ranking.

However, in a radio segment on ABC Sydney radio an Australian Climate Council Spokesperson admitted that this ranking does not take into greenhouse gases released over the life cycle of a vehicle, only tailpipe emissions. For me this is not good enough, if we are going to tackle emissions globally, we need to think globally, just looking at tailpipe emissions simply exports Australian emissions to those countries who are manufacturing EVs and this is short sighted.  Proverbially as a country Australia will be ‘robbing Peter to pay Paul’ when it comes to global greenhouse gas emissions.

The Australian Federal Government’s consultation process on Australia’s fuel quality standards is a move towards lower emissions from Australia’s light vehicle fleet. But just like EVs, there is more to Greenhouse Gas Emissions than just tailpipe emissions and if the Federal Government wants to be a global leader in our strive for net zero emissions by 2050 then Life Cycle Analysis’ (LCAs) should be core to the policy decisions that are being made. So, what the Federal Government should be doing is obliging car companies who sell vehicles in Australia to publicly release their LCAs so that the end consumer can make an informed decision about their new car purchase and its overall impact on greenhouse gas emissions.

Battery Electric Vehicles (BEVs)

A Battery Electric Vehicle (BEV) is a pure electric vehicle and runs only on power from a battery which transfers to the vehicle’s wheels via a motor/s. These motors can be mounted on the front or rear wheels or both wheels to create all-wheel drive.

The range of a BEV is generally limited by the size of the battery fitted to the vehicle, with the larger the battery the greater the range. But your driving style (aggressive or smooth), where you drive (urban or highway), environmental factors such as temperature or rain can impact on the range of your EV.

Car companies will generally claim a Worldwide Harmonised Light Vehicle Test Procedure (WLTP) range for their electric vehicles, but just like claimed fuel use of internal combustion engine (ICE) vehicles this WLTP range rarely reflects real-world range.

After driving EVs from a number of car manufacturers I have found that the real-world range of an EV is generally 25% less than the claimed WLTP range. I calculate energy usage manually based on percentage of battery used and kilometres driven and not via the on-board computer.

Once the energy from your BEV is consumed you will need to charge the vehicle. This can be done at home/work using a standard 240V AC plug and this charges at around 2kW per hour from my experience. If you want to charge faster at home/work then a wall unit will need to be installed and in Australia this is most likely to be a 7kW charger due to limitations on the electricity supply in Australian homes.

If you are on the road and require some extra charge you will need to go to a public DC charging station with charging speeds usually between 50-350 kW of power. The speed that your vehicle charges from a public station will depend on size of battery, state of battery (empty vs. full), maximum charging rate of vehicle, maximum charging rate of the chargepoint and environmental factors (charging can take longer in colder temperatures).

Plug-in Hybrid Electric Vehicles (PHEVs)

A plug-in hybrid vehicle combines a smaller battery powered motor with an ICE to enable you to achieve a greater number of kilometres driven from each litre of petrol used. The number of kilometres available for pure EV driving will depend on the size of the vehicle’s battery, your driving style and environmental factors.

The on-board regeneration of the battery is limited and once the PHEV battery is empty the vehicle will revert to propulsion from the ICE. Like a BEV the battery, the PHEV can be charged at home/work or at a public charging station.

Depending on how and where you drive a PHEV can greatly increase the efficiency of your vehicle, but in my experience the claimed fuel use figures of PHEVs are not achieved in the real-world.

Hybrid Electric Vehicles (HEVs)

Like a PHEV a hybrid vehicle (HEV) combines a battery powered motor with an ICE with the difference being that the battery of the HEV is charged while the vehicle is being used and it does not need to be plugged in.

Hybrid vehicles can be driven in full EV mode for short distances, at low speed and the battery is recharged under braking and when the vehicle is not using the engine, for example going down a hill or slowing down for traffic lights so they work most efficiently in city environments.

HEVs enable you to improve the overall fuel efficiency of the vehicle and I have achieved 4.8L/100km in a hybrid Toyota Camry, 5.1L/100km in a hybrid 2WD Toyota C-HR and 7.8L/100km in a hybrid Toyota RAV-4.

Mild Hybrid Electric Vehicles (MHEVs)

A mild hybrid electric vehicle combines a small battery powered motor with an internal combustion engine and they cannot be driven in pure EV mode. The small battery can be charged while the vehicle is driven and the power from the battery can be used for modest performance improvements and for providing increased efficiency by powering some of the vehicle’s electrical systems.

I have driven MHEVs from numerous manufacturers and from my experience I have found that the addition of the mild hybrid system does little to improve the overall performance or fuel efficiency of the vehicle.

Photographs by Driven Women Magazine.

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