We know engines and transmissions can last for over one million kilometres if maintained well. What about electric motors and batteries? Internal combustion engines that are known to have run a million kilometres are actually rare. Few owners keep their cars running that long and even those who have persevered obviously overhauled the engine several times during the course of its life.

With electric vehicles (EV), the question of longevity revolves around the batteries and motors. We know from our experiences with rechargeable batteries at home or office that their storage capacities gradually diminish over time. Eventually, a battery replacement would be necessary if the device is to continue to function. Mobile phones are the most typical example.

Battery technology for EVs is still at a relatively early stage. There is not much long-term information available on lifespan. Most EV makers offer warranties of between 80,000km and 100,000km. The batteries could probably continue beyond that mileage albeit with increasingly reduced storage capability.

Compared with an internal combustion engine, an electric motor's biggest advantage is that it has no reciprocating parts. It is a pure rotary device and does not have issues with imbalance in operation.

Motors have been in use in transportation, industries and commercial buildings. Most of these, such as air-conditioning and ventilation blowers, conveyor belts, water pumps, and of course our trains, run continuously for several hours a day, year in and year out.

The main rotating component, called the armature, is the only moving part. Electric motors do not need oil change, oil filter, spark plugs, fuel filter, timing belt or radiator. They have negligible wear and tear. Even if modern EVs have not been around long, the track record of motors is long enough to suggest that an EV's motor will outlast several battery swaps and several hundred thousand kilometres.