What is a plug-in hybrid?

Combining electric power with an internal combustion engine, plug-in hybrid cars offer flexibility on the road with improved efficiency so you can go further for less while reducing carbon emissions.

Plug-in hybrid cars are different from electric cars and traditional petrol and diesel cars. But what is a plug-in hybrid car and how do they work? Find out everything you need to know below.

Find out more about your hybrid car options in our guide: HEV, BEV and PHEV explained: What's the difference? With our electric car guides, you can also learn more about choosing the right electric car for you and how hybrid cars work to help you make your decision.

A plug-in hybrid car, or a PHEV, combines an electric motor and a traditional internal combustion engine. It can operate using electric power only, fuel power only or a combination of both.

Plug-in electric vehicles have a large battery that can be recharged by plugging the car into an external charger like a home charging or public charging station. Plug-in hybrid cars can travel using all-electric mode for short distances, with the fuel engine kicking in when the electric charge has depleted.

They’re a good option for reducing fuel consumption and emissions and make a great alternative if you’re not quite ready to switch to fully electric driving.

A plug-in hybrid car combines an internal combustion engine with an electric motor. The car has a rechargeable battery that can drive the car over a limited range depending on the make and model. The internal combustion engine kicks in when the battery is depleted or when more power is needed.

For example, the BYD Seal U-DMi has an all-electric range of up to 78 miles - boasting up to 699 miles of combined range when using both the electric motor and internal combustion engine.

The electric battery needs to be charged by plugging into a charging station, a charging point at home or a 3-pin plug. Once the electric range is used up, a plug-in hybrid will automatically switch to hybrid mode, where the electric motor and the ICE work together. The combustion engine can take over when heavy acceleration is needed, like motorway driving, long trips and when the car’s battery is low.

PHEVs have a larger battery than other HEVs which means they can cover longer distances with all-electric driving. PHEVs are also different to HEVs because they can be plugged into an external charger. Plug-in hybrid vehicles also use regenerative braking to boost the battery, extending the electric range and improving efficiency.

Plug-in electric cars charge when plugged in and when driving. To recharge your PHEV, you’ll plug it into an external power source - whether that’s a home charger or a public charging station.

Your PHEV will also recharge as you’re driving. The engine and regenerative braking can charge the battery, extending your PHEV’s all-electric range.

Even if you don’t plug your PHEV in to charge, you’ll still be able to drive it powered by the internal combustion engine. PHEVs can still be driven if you don’t charge the battery. With the help of regenerative braking, your PHEV will be powered by its internal combustion engine and will use the energy converted from braking to improve efficiency.

When it comes to choosing a plug-in hybrid vehicle, there are a few factors to consider, including your driving habits, access to charging infrastructure and your carbon footprint.

A hybrid car is a good option for those commuting — they’re well suited to stop-start traffic, but they’re also a good option for those travelling longer distances who don’t want to worry about electric range.

Let’s weigh up the advantages and disadvantages of plug-in hybrid cars:

• Fuel Saving: The electric motor in PHEVs works with the ICE for improved fuel efficiency, meaning you can travel further for less.

• Environmental benefits: PHEVs are a great alternative to ICE cars. They can travel further for longer on pure-electric power, meaning lower emissions, reducing your carbon footprint.

• No range anxiety: The electric motor is always backed up by the internal combustion engine, so not only can PHEVs go further for longer, but you also don’t need to worry about running out of charge; the ICE will kick in when the electric charge has depleted.

• Flexibility: It doesn’t matter whether you’re regularly commuting over shorter distances or you’re off on a long journey, PHEVs can do both. On short journeys, take advantage of all-electric driving. On long journeys, the engine will kick in for more power or to increase range.

• Lower repair costs: Wear on PHEV engines is reduced as they work alongside the battery. This typically means less wear and tear, so you can save on repairs.

• Higher upfront cost: Plug-in hybrid cars tend to be more expensive upfront than traditional ICE cars. This is due to the added cost that comes with the larger battery and a more complex drivetrain.

• Limited electric range: While you can drive in all-electric mode with a plug-in hybrid car, it’s not a fully electric choice. PHEVs have a lower pure-electric range than fully electric vehicles.

• Access to charging infrastructure: You will need access to charging infrastructure to get the most out of your PHEV. You’ll need a home charger or access to public charging, so keep this in mind when purchasing your car. PHEVs also tend to charge slowly, meaning it takes longer to charge the battery to 80%.

• Heavy on the road: PHEV batteries add extra weight to the car in comparison to conventional hybrid and ICE cars. This can reduce fuel efficiency when petrol or diesel driving.

• Complex to repair: While PHEVs don’t require as much maintenance as a traditional petrol or diesel car might, they are more complex to repair as they have two powertrains — the engine and the battery. Parts can be more expensive to buy and labour costs may also be more expensive.

If you’re unsure about whether a plug-in electric vehicle would suit you, weighing up your options can be helpful. If you’re looking to reduce your carbon footprint and experience some of the most advanced tech on the market, choosing an electric car could be a great option.

If you don’t have access to charging infrastructure but you’d still like to do your bit for the environment, explore self-charging hybrid electric cars. If you’re simply looking for a way to improve fuel economy without changing your driving experience, a mild-hybrid car could be a great option.

BYD’s advanced, innovative hybrid technology is available in the BYD Seal U DM-i. For more about how it works, take a look at our Super DM technology page.