As a result, some manufacturers refer to them as ‘self-charging’ hybrids, though this term has caused plenty of controversy, with some critics believing it’s misleading to buyers who might think these cars can charge up by themselves while parked. 

It’s true that these cars’ batteries do charge themselves, but they require the ICE to be running to do so, and consequently, fuel to be burned in the production of that electricity,  as the battery is quite small. As a consequence, they can only run on electricity alone for a few miles if they run out of fuel. 

However, as a result of this they aren’t that much heavier than normal petrol or diesel cars, so relatively little electricity is needed to provide a boost in performance or to keep the car moving in slow traffic. 

Indeed, it’s urban traffic in which hybrids of this type tend to work best. In these conditions, the constant speeding up and slowing down results in lots of regenerative braking, which charges up the battery more, means there’s more electric power available to boost the ICE, or even allow it to cut out altogether.

Plug-in hybrids

As the name suggests, the main thing that differentiates hybrids of this type is that they can be plugged in to a socket to charge up their batteries.

Most plug-in hybrids (or PHEVs, for short) have a larger battery and electric motor than do full hybrids, and as a result, they’re usually able to run on electricity alone for longer. A typical PHEV can travel around 30 miles on electric power, allowing its owner to complete short round trips without ever using the petrol engine.

The downside by comparison with a fully electric car, of course, is a much smaller electric-only range, and PHEVs are much less efficient too, as they must carry around the weight of the ICE and its fuel. However, when the PHEV runs out of charge, it can switch seamlessly to its ICE, assuming there’s fuel in the tank of course.