What Are Range Extender Electric Vehicles?

Range Extender Electric Vehicles or REEV, used to be a great alternative to regular internal combustion engine (ICE) ones. But we don’t see or hear much about them these days, why is that?

Traditional hybrid vehicles use a regular petrol engine to power the wheels. It is assisted by an electric motor that receives power from a small battery pack. The idea here is that the electric powertrain will help reduce the load placed on the internal combustion engine when the car is in motion.

This is why hybrid vehicles offer far better fuel consumption than regular petrol-powered cars. Range extender vehicles on the other hand are “reverse hybrids”. They rely on an electric motor and power from the battery pack for propulsion like a conventional EV.

A REEV also has an internal combustion engine that helps generate electricity when the vehicle’s battery power runs low. It doesn’t power the wheels directly, instead works with an electricity generator to develop the power. Its sole purpose is to keep charging the batteries as and when needed.

Traditional hybrid vehicles have both petrol engines and electric motors to send power to the wheels. They can travel a certain distance on electric power alone, but the engine fires up the moment the battery charge is depleted, or if the performance demands exceed what the electric motor can deliver.

An example of a REEV is the Chevrolet Volt that was sold in the US from 2011 to 2019. On a full charge, the first gen car could travel about 61km (2nd gen could do 85km) before needing the petrol generator to kick in to assist it. The car could also receive power from regenerative braking. 

REEVs offer impressive range because the electric motor does most of the heavy lifting, while the petrol/diesel generator steps in only when charge runs low. It solves the fundamental problem with early EVs that didn’t have the range to consider them useful vehicles.

What happened to the REEV? 

The Chevrolet Volt and BMW i3 Range Extender were two of such vehicles that seemed good on paper but in practice, didn’t really turn into success stories. See, they cost more than EVs because of the inclusion of the generator. 

Since the generator is a type of ICE, maintenance costs are far higher due to frequent oil changes and other servicing requirements that need to be done at scheduled intervals. In addition to this, advancement in battery technology has rendered REEV obsolete for the time being.

There’s also an ever-growing network of public fast DC chargers that can top batteries in about 30 minutes. This has made EVs viable replacements for ICE vehicles. As such, we REEVs aren’t needed like they were a decade ago.