What is a range extender? And can I buy an aftermarket one?

What’s a Range Extender?

Not something that makes your wifi powerful enough for the whole street to abuse, but a battery-electric vehicle (BEV) paired up with... fossil fuels.

Wait, what? How the heck does that work?

Because the electric motor drives the axle from a battery, this is an electric car. But there’s an on-board petrol-drinking generator that can recharge the battery once it's depleted, hence the ‘range-extending’ title.

Sounds suspiciously like a hybrid. What’s the difference?

Sure, both of them utilise an internal combustion engine (ICE) and electric motor, so you’re right. But where the ICE drives the axle in a hybrid (whether it’s “self-charging” or a plug-in hybrid (PHEV)), the electric motor does all the work in a range extender.

Semantics?

Hardly. Since you're not connecting the engine to the wheels (only to the battery), carmakers can use a much simpler design – no driveshaft, no clutch, no gearbox. Plus, as it's not a geared engine, it can run with the optimal fuel efficiency and last a lot longer, too.

I'm with ya. So I get double bubble on the fuel efficiency front?

Well, triple bubble if you think about it. Not only are you driving around on delicious, earth-friendly electrons, you've also got an engine with the sweetest spot of energy-extracting efficiency to send more electrons to the battery and you're still capitalising on regenerative braking tech.

Gotcha. What's the catch?

You need a Scrabble board to figure out some of the titles. REX, REEV, EREV are some of the basic acronyms. REX stands for, er, Range Extender, a REEV is a 'range-extending electric vehicle', and an EREV is not a Bristolian call-to-arms even if it reads like one. It stands for 'electric range-extending vehicle'. 

With all the engineering knowledge in all the land, you'd think a bunch of clever folk could get a few letters figured out in a similar order, eh?

Anything else I should know?

As the engine doesn't drive the wheels directly, there's far less vibration, so you still benefit from the quiet that is an electric vehicle.

Plus, all this gubbins is far more cost-effective for manufacturers to tool up for, meaning the consumer cost of the range extender should be more attractive, too.

SOLD. What cars can I buy with one of these amazing range extender set-ups?

Erm, that's a bit tricky actually. The tech debuted on the Vauxhall Ampera (Chevy Volt for our US friends, and Opel Ampera to our mates on the continent). It was well-deployed in the BMW i3 (REX), and some folks living in countries with more extensive land mass than Britain have looked to mod with aftermarket, insurance-invalidating set-ups.

The now-cancelled Ineos Fusilier was meant to have one, and Genesis intends to put one in the GV90 come 2027 (though that's not bound for UK shores just yet). VW – in collaboration with SAIC - showcased its first range-extending ID model, the ID.ERA SUV at Auto Shanghai 2025, but that was just a concept.

With ZF creating the next-generation of range-extending powertrains after "increased demand from the industry", expect to see more Rs, Es, and Vs in model names at some point in the future. You're hunting the used car market for the odd Fisker Karma otherwise.