An EV range extender (EREV) is a system added to a battery-electric vehicle (BEV) that increases driving range by generating additional electricity once the battery is depleted. It is essentially a secondary power source—commonly a small internal combustion engine (ICE) or sometimes a fuel cell, micro-turbine, or auxiliary battery—that recharges the main battery or directly powers the electric motor.

Here’s a breakdown on how it works

  1. Battery First:

The vehicle drives primarily as a normal EV on its main traction battery.

  1. Range Extension Kicks In:

When the battery reaches a low state of charge, the range extender activates.

  • In most designs, the ICE or fuel cell powers a generator that produces electricity to recharge the battery.
  • The wheels remain powered by the electric motor(s), not the ICE.
  1. Continuous Driving:

This allows the driver to continue driving beyond the pure EV range, eliminating range anxiety.

 

 Common Configurations

  • ICE Generator (most common):

A small petrol or CNG engine connected to a generator. Example: BMW i3 REx, Chevrolet Volt (though the Volt could also drive wheels mechanically in some modes).

  • Fuel Cell Range Extender:

A hydrogen fuel cell provides electricity once the main battery is low.

  • Battery Trailer / Auxiliary Pack:

A supplemental battery pack (sometimes in a towable module) adds temporary range.

 

Advantages

  • Extends range without needing charging infrastructure.
  • Keeps EV driving dynamics (electric motor propulsion only).
  • Smaller ICE compared to hybrids → lighter and cheaper.
  • Flexibility for markets with weak charging networks (like Nigeria & much of Africa).

 

Challenges

  • Added cost, weight, and complexity.
  • Still uses fossil fuels (if ICE-based), so not fully zero-emission. But consumes gasoline at rates of 2.8 liters / 100 km or less.
  • Regulatory classification (some markets treat them as hybrids, not full EVs).

 

Examples

  • BMW i3 REx → Small 647cc two-cylinder petrol engine as generator.
  • Chevrolet Volt → Used ICE as both generator and, in some modes, direct drive.
  • Mazda MX-30 R-EV (2023) → Rotary engine used only as generator.
  • Various Chinese EREVs (Li Auto, Dongfeng, Seres, etc.) are booming in China, especially for larger SUVs where long range is needed.

 

For SAGLEV’s Nigerian/African market, EREVs could be highly strategic:

  • A CNG-based range extender could leverage Nigeria’s abundant gas resources, keeping costs low.
  • It solves range anxiety where charging infrastructure is still limited.
  • It could be a good transitional technology while full EV infrastructure scales.