Today is April Fools’ Day, and the temptation to write a glossary of entirely fabricated road testing and vehicle dynamics terminology is strong – but the definition of hoverskid, rimsnatch, elastosymptomatic torsion and syncopated stroking will have to wait.

I would like to address the topic of regenerative braking, or regen: the way that electrified and electric cars recover kinetic energy and save it for later reuse.

The way people talk, think and even feel about regen amazes me. It’s a real thing: in essence, just an electric motor being used in reverse, as a generator, to send current in the opposite direction to the one in which it typically travels. But I’m pretty sure some people think it’s magic; voodoo; whatever Matthew McConaughey was talking about in that line from The Wolf of Wall Street (“it’s a whazy, it’s a whoozy, it’s fairy dust”, etc).

Some evidence presented itself just the other day. A representative of a car company (which I won’t identify) was sufficiently confused about the regen of the EV he was launching – and how it was accounted for – that he told me it wasn’t included in the trip computer’s numbers.

“That’s why our EVs always look less efficient than they really are,” he said. “You have to add the extra energy that you’ve regenerated on top of the efficiency and range figures displayed.”

Imagine my incredulity. It took me all of 10 minutes, out on the test route, to lay waste to his hypothesis. Some freewheeling down a hill was involved. It was fun.

But it got me thinking. Regen is the secret weapon of hybrid and electric cars – but it is also fetishised. Some drivers of electrified cars seem to delight in it. You see them out there, speeding up just to slow back down, believing they can accelerate as hard as they like, because regen will give them all of the energy back again – as if they’ve discovered perpetual motion.

It takes me back to a very informative few hours that the Autocar team once had, close to 20 years ago, with the late, great Richard Parry-Jones, then chief technical officer at Ford. He was briefing us on the future of the passenger car, and he explained the central truth about regen so eloquently that it has resided in my head ever since.

This was the thrust of it: “The great efficiency gain of electric motors concerns energy lost to heat. Combustion engines typically run at about 40% thermal efficiency, and motors are much better than that.

“Beyond that, the second law of thermodynamics tells us, every time you convert energy from one form to another – which happens when an electric motor is driving a car forwards and then scavenging energy to slow it down again – it costs you something. No conversion of energy is 100% efficient. If an electric motor lets you recover even half of the energy you’ve invested to make an object move in the first place, it’s going some.

“Even so, if all regen does is help you recapture at least some of the energy that your brakes would otherwise give off as waste heat, it’s worth having because in real-world driving we do tend to use the brakes, so why waste it?