The EV battery trick that can save you money on the road: 'Very efficient'

The electric car feature is delighting owners after years with a petrol powered motor. Here's how it works.

The MG electric car being charged (left) and the Aussie driver pictured smiling (right).
An early EV adopter in Australia is spruiking a surprise benefit of battery powered cars. Source: Supplied

A surprising feature of electric vehicles has become a new talking point after one early adopter revealed a little-known trick that pumped power back into her car’s battery — while she was driving. Motorist Jacinta Green has shared her delight at watching her car's battery "tick backwards like the Ferrari in Ferris Mueller’s Day off" as the battery gained power while on the road.

Jacinta Green, who lives in rural Bungaba in NSW, said she was driving her MG Essence in sports mode and KERS (Kinetic Energy Recovery System) through slow-moving traffic in the Blue Mountains region just outside Sydney when she noticed power was going back into the battery.

She told Yahoo News Australia the trick was made possible through regenerative braking, a feature on all EVs, and saw her car battery charge go from 23 per cent to over 35 per cent full while driving between 35 and 40km/h and braking often.

“I’ve seen my battery per cent decrease, slow down or increase a per cent or two but this was the first time I’ve seen it tick backwards like this,” Green said. “I put (on) about 14 per cent in the space of a few kilometres.

“This was the first time it’s been so visible. When the car slows down, it uses the power of the car slowing down to recharge the battery. It might only do it for a couple of seconds but I’ve never seen anything greater than -19. This time it was at -21 per cent," she said.

This means that the car was using 21 per cent less power, which goes back onto the battery. “Basically, it uses the energy and momentum of when you are braking to charge."

EV sign (left) EV charging parking spot in car park (right).
Finding charging stations is easy in populated areas but there are fewer in rural or regional areas, although more are being built as EV take-up rises. Source: Getty

She shared her experiences with fellow EV drivers in a Facebook group and many said they enjoyed the feature as well. One EV owner responded: “Today, I had a small run of hills and thought I’d switch over to the other screen, I was very surprised to see it pumping 40-50 amps into the battery with just mild slowing down.

While another said: “It’s very efficient. Makes spirited driving much less costly than a fuel car, that’s for sure.”

Her EV has three modes – normal, eco and sports – with the latter being “heaps of fun” to drive, particularly around corners and more economical in slow traffic.

Because of her remote location, there are few traffic lights where Jacinta lives so braking and driving in congested traffic was not something she often encountered.

Since buying her EV 18 months ago, Green said she and her partner, who live off-grid with just a 5 kilowatt solar panel, had driven 28,000km while spending an incredible $16 a week in charging costs.

“He drives it every chance he gets and leaves his diesel truck at home, saving $140 a week,” she told Yahoo. “We drive without thinking about it because it’s so cheap.

“In the old days, it was, ‘S**t, we need to fill up, how much is that going to be?’ Or, ‘Petrol has gone up again this week’ — all that has disappeared. We just don’t think about it.”

Jacinta Green (left) and EV charging point (right).
Jacinta Green says that owning an EV has made life a lot easier. Source: Supplied/Getty

Edwin Higginson, director of Australian Electrical Vehicle Specialists, told Yahoo News: “If you’re driving an EV, it has regen but physics still applies... You use more energy going forward rather than slowing down so you can save a lot of power.

“With regen braking, you are receiving power that goes back into the battery, you can see the percentage increase as its slowing down.

“It is receiving energy, so in actual fact you are effectively turning your motor into a generator so it is then pushing power back into the battery. But you are never going to be able to gain more power back into the battery than the energy you need to drive it,” he added.

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