What is a self-charging hybrid car? | CAR Magazine

What is a self-charging hybrid car?

Published: 27 February 2023 Updated: 27 February 2023

► The term self-charging hybrid explained
► How do they work?
► Why are some people annoyed about the term? 

If you’re looking buy a hybrid car in 2023, there’s more choice than ever. In addition to every bodystyle you can think of – from SUV to compact city runner – hybrid technology also comes in a few different forms. In addition to plug-in hybrid cars and mild-hybrid cars, some brands also produce self-charging hybrid cars. Designed to offer many of the perks of hybrid tech without the hassle, self-charging hybrids are becoming an increasingly popular way to get the range benefits of a combsution engine paired with the economic and environmental benefits of an electric vehicle. 

What is a self-charging hybrid? 

Like any other type of hybrid vehicle, self-charging hybrids fuse a traditional ICE (internal combustion engine) with an electric motor. There to aid the vehicle under acceleration, the electric motor is driven by a small battery. Unlike other hybrid cars, self-charging cars don’t need to be plugged in – though that does mean they have a shorter EV-only range than their plug-in hybrid counterparts. 

Lexus self-charging hybrid car

How does a self-charging hybrid car work? 

A self-charging hybrid pairs a petrol or diesel (more commonly petrol) engine with an additional electric motor. However, unlike plug-in hybrid cars, self-charging hybrids have smaller batteries, and do not require topping-up from an external source – instead, they rely purely on energy retrieved from braking and coasting. This ‘rescued’ energy is sent to the motor to assist the petrol or diesel engine under acceleration, thus improving efficiency and fuel economy. It’s also used in low-speed, stop-start traffic. 

Many self-charging hybrids can run in an EV-only mode, but don’t expect anything near the range of an EV or a more traditional plug-in hybrid car. The short-term nature of this charging and powering loop means that self-charging cars have smaller batteries than PHEVs, and therefore can’t store as much energy. 

Self-charging ford hybrid

What’s the difference between a self-charging hybrid and a plug-in hybrid? 

The main difference between a self-charging hybrid and a plug-in hybrid is that the former isn’t plugged in – instead it needs to be in motion its charge its batteries. 

What are the benefits of self-charging hybrids? 

Self-charging hybrids feature many of the benefits of a hybrid powertrain but lose some of the downsides. Unlike more conventional hybrids, self-charging hybrids don’t need to be topped-up all the time. If you want to treat your car just like a petrol or diesel vehicle, but want improved economy, self-charging hybrids are certainly worth looking at. 

Toyota CH-R hybrid

It’s important to remember that you do need to charge a plug-in hybrid to get the economic benefits of its hybrid system; otherwise, you carry around the dead weight of large, heavy battery without any benefits and you’ll find the mpg is worse than a standard car. The smaller batteries of a self-charging hybrid remove this necessity. 

Still, there are tradeoffs: the smaller battery means that self-charging hybrids have a far shorter range when it comes to electric-only driving. 

What’s wrong ‘self-charging’ as a phrase? 

Ever since the term ‘self-charging’ was first coined a few years ago, there has been discussion around whether or not it misleads consumers. For example, it’s important to remember that self-charging cars don’t charge on their own – instead they need to be in motion – and that costs fuel.

What’s more, the term also implies that self-charging cars are able to generate and store the same amount of electricity as a plug-in hybrid, when in reality they’re charging a significantly smaller battery. While plug-in hybrids can be described as having an ‘electricity bath,’ self-charging hybrids can be seen as having a sink, usually used for quick storage and almost immediate use.  

By Curtis Moldrich

CAR's Digital Editor, F1 and sim-racing enthusiast. Partial to clever tech and sports bikes