If you’ve come across the term ‘self-charging hybrid’ in adverts for cars for sale in the UK and wondered what it means, this page is here to help.
The phrase originates from an advertising campaign by Toyota. In a stroke of genius that plays deeply on the range anxiety fears surrounding 100% electric cars – meaning the constant worry about when you might run out of charge and/or where you might charge back up again – the term instantly underlines that hybrid vehicles don’t have to be plugged in at all.
Some hybrid cars combine their electric motor drive with a conventional petrol (or occasionally diesel) engine. This means you’ll always be able to easily refuel them at a petrol station and soon be on your way again.
More specifically, the self-charging hybrid term is usually applied to what are otherwise known as ‘full hybrids’ – naturally enough, the kind of hybrid that Toyota has built a great reputation around pioneering and subsequently refining. A full hybrid is one that is capable of running on electric power alone for a significantly useful amount of time, but doesn’t have a battery big enough to require any form of plug.
Are self-charging hybrids the only kind you can get now?
There are two other main types of hybrid car available: mild hybrids and plug-in hybrids.
Mild hybrid electric vehicles (MHEVs) have only very small batteries and tiny electric motors, which interact with the engine in a very specific way. These systems enable more efficient stop-start processes, can recover energy that would be lost when slowing down more efficiently than conventional non-hybrid cars, and can use their electric motor to give the engine a small performance boost at low revs.
But until very recently, they could not drive the car on electric power alone. A few new mild-hybrid vehicles, such as the Alfa Romeo Tonale, can use the motor to move the entire vehicle now, but only at very low speeds. So, while MHEVs are effectively self-charging as well, they aren’t as zero-emissions capable as full hybrids, which can switch off the engine at much higher speeds and use the electric motor alone a far higher percentage of the time.
Plug-in hybrid electric vehicles (PHEVs) are different to regular full hybrids because they have batteries large enough to power the electric motor constantly for much longer periods – usually for at least 30 miles until they run out. These too can be self-charging, as you can divert power from the engine to recharge the battery while driving. But this isn’t very fuel efficient, as it places greater strain on the engine, defeating the fuel-saving advantages of the hybrid drive.
As such, it’s much more sensible to recharge a PHEV by plugging it into the mains whenever the battery needs topping up – hence plug-in hybrid. The larger battery also typically makes them more expensive to buy, a cost you will only recoup if you are able to make maximum use of the electric motor drive – which you can only do if you plug in to charge regularly and mostly cover journeys that fall within the electric-only driving range.
Does that make self-charging hybrids the most useful choice?
You’ll find mild hybrid technology is almost becoming standard on all new cars now, as manufacturers battle to meet ever more stringent emissions standards. But the fuel savings MHEV technology represents, while worthwhile, are still very modest compared to those a full self-charging hybrid can deliver these days. So, if you’re looking for a good efficiency-to-cost ratio, a self-charging hybrid is a very good option. The latest Toyota and Honda models, for example, are mostly capable of over 50 miles per gallon in the real world despite using a petrol engine.
Plug-in hybrids can be far more efficient still, if driven in circumstances that allow you to make maximum use of the electric motor – as outlined above. But there’s an argument that if you can manage that you may as well go for a 100% electric car, which will be even more efficient. As such, the additional cost of a PHEV versus a full self-charging hybrid may not be worthwhile.
The truth is that all three technologies – as well as 100% electric cars – have their place on our roads now. Which is best for you will come down to both your budget and the type of driving you generally do.