What is a Plug-in Hybrid car and how do they work?

It can often be confusing for the average motorist when it comes to understanding all of the jargon that surrounds hybrid technology in cars. 

What are the different types of hybrid cars? How do they work? Which is the right hybrid car for me? 

Here we're going to have a look at plug-in hybrids and explain how and why they work in the way that they do. 

What is a plug-in hybrid car?

A Plug-in Hybrid Electric Vehicle, or PHEV for short, is a car that uses two different power sources. A PHEV uses a traditional internal combustion engine, such as a petrol or diesel, along with an electric motor and battery. 

You'll generally find PHEV technology in larger vehicles, such as crossovers and SUVs. The bigger the car, the bigger the battery needed to power it. And the bigger the battery, the bigger the source of power required to charge it, which is why they need to be plugged in. 

A PHEV requires a cable to connect the car to a mains power source - usually a wall box charging point at home or a public charging station. .

How does a plug-in hybrid car work?

Essentially, a plug-in hybrid car needs petrol or diesel to run, so it requires taking to the filling station just like any other non-hybrid. As the name is a bit of a giveaway, a plug-in hybrid also needs to be plugged in to charge its battery.

Once fully charged, most PHEVs have an eco-mode feature that can be used to drive on pure electric power. The sizeable batteries are typically powerful enough to cover up to 30-50 miles, depending on the type of driving. 

Cruising on the motorway at 70mph in eco-mode will obviously require the PHEV battery to work a lot harder than a city commute in heavy traffic. 

For the majority of the time, a PHEV will use its combustion engine and electric motor together like a regular hybrid car. The car itself will work out what is the best course of action to provide maximum efficiency at any given time, as long as those batteries are charged, even on longer journeys. 

How is a plug-in hybrid different from a normal hybrid car?

There are three different types of hybrid car: Mild Hybrid, Full Hybrid and Plug-in Hybrid. They are designed to be environmentally friendly, by maximising fuel economy and helping to keep running costs low.  

Mild hybrid cars are sometimes known as self-charging hybrids. They have the smallest batteries of all the hybrid versions, therefore are usually found in city cars. The Suzuki Swift uses a 1.2-litre engine and 2.3kW electric motor. 

Mild hybrids are more reliant on fuel to power them but still use regenerative braking to reroute energy into the battery - hence the name self-charging hybrid.

Full hybrid, or Hybrid Electric, vehicles are typically bigger than their mild hybrid counterparts. The Suzuki Swace is a full hybrid estate car and uses a 1.8-litre engine and a 70kW motor. Again, full hybrids like the Swace use regenerative braking to help power the battery. 

Full hybrids require larger batteries and a more powerful motor, so it wouldn't make sense to put them in a smaller car. 

The Suzuki Across PHEV is the brand's large SUV plug-in hybrid. The Across uses a 2.5-litre engine, 134kW electric motor, and an 18.1kWh high-capacity lithium-ion battery. Due to the battery's size, it is mounted beneath the car's floor and needs to be plugged in to charge.

How often should I plug-in a PHEV?

You should plug in your PHEV as often as you can. If the battery has no power in it, the car will run predominantly on its petrol engine, which sort of defeats the object of driving a hybrid.

How long does a PHEV take to charge?

The time it takes for a PHEV to charge differs from model to model. On a normal domestic charge, it might take up to five hours to fully charge a PHEV. Using a high-capacity wall box or public charger will cut the charging time down to around three hours. 

These figures can seem rather lethargic compared to the ultra-rapid charging times of the latest fully electric vehicles. But you need to remember that the battery in a PHEV is still pretty small compared to those needed to power an EV. 

Ideal times to charge your PHEV is overnight when electricity costs will be lower, or when you're at work so it'll be fully charged and ready for the commute home.

Should I buy a plug-in hybrid car?

A plug-in hybrid is a great choice if you're looking for an eco-friendly car but need a larger vehicle like an SUV. They're are generally not as expensive to buy as a fully electric car and provide greater fuel efficiency than your regular hybrid vehicle. PHEVs provide a great balance between hybrid and electric cars. 

Using a PHEV on the school run and urban work commutes is really where the plug-in hybrid tech is at its most effective. You can use the eco-mode for short trips without using a whole lot of fuel, and then pop the car on charge at work ready for the journey home.

It will keep your petrol costs low while also being friendly to the environment. You might even be able to evade city centre congestion charges if you use the eco-mode wisely enough.