How do self-charging cars work?

Toyota, Lexus and Kia use self-charging as a term to describe their mild hybrids.

Mild hybrid doesn’t sound as exciting or technologically advanced as a self-charging car, which is probably why their marketing departments opted for the more mysterious and intelligent-sounding self-charging terminology.

How Do Self-Charging Cars Work?

A self-charging hybrid has a small battery and an electric motor. When the vehicle brakes, the initial phase of braking is used to charge the battery. Brakes (disks and pads) then kick-in after.

This is a basic form of regenerative braking (or regen) something plug-in hybrids (PHEVs) and electric vehicles (BEVs) do too, but to a greater degree and effectiveness.

The small amount of energy recovered from braking is then able to be used to drive a limited distance.

What Powers a Self-Charging Hybrid?

Exhaust pipe emissions on a self-charging car

Unfortunately, a self-powered car breaks the laws of physics, as the energy must come from somewhere. In one of Kia/Lexus/Toyota’s mild hybrids, the power comes from burning fossil fuels – the petrol in the internal combustion engine.

This means self-charging cars are 100% powered by petrol. All the propulsion achieved is down to petrol – since the cars don’t plug-in.

If we refer to mild hybrids as self-charging, we should really refer to all petrol and diesel cars as self-charging, since these cars don’t need plugging in to charge their 12-volt battery which powers the wipers, headlights and other electrical ancillery services.

How Far Can A Self-Charging Car Travel?

Toyota et al claim that their mild hybrids can be driven over 50% of the time on “pure electricity”. That makes them seem awfully green, given we tend to associate electricity with being green and petrol with being polluting. This claim is misleading for two reasons:

  1. It’s crucial to remember that Totota reference time not distance – if you drive in stop-start traffic, the engine might be off for a large proportion of the time as you’re stationary. Some of the slower speed driving may be achievable using the battery, but because the battery is very small, it will drain extremly quickly and require recharging – so the petrol engine turns on. In terms of distance driven, I’d estimate only around 5-10% of miles/kilometers are driven using the battery.
  2. All the electricity used to driver is generated by burning petrol, so it’s certainly not the clean energy you can get from the grid or solar on the roof of your house for example.

Do Self-Charging Cars Exist?

Will we ever see a car that can power itself? In the Toyota sense of self-charging, no. It’s not possible to drive a mild hybrid without putting petrol in it.

Lightyear One

However, there are projects like Lightyear One, working to create cars that you may never need to plug-in! These are pure electric cars (not hybrids, so no fossil fuels) and can be charged by plugging-in, or from the solar panels built into the roof, bonnet and boot! ☀️⚡🔋🚗

Lightyear are aiming to be able to charge an impressive 12 kilometres (7 miles) from 1 hour of sunshine charging – using the solar panels on the roof! For those who drive short distances, or only travel infrequently, that could mean you’d never need to plug-in!

More info on the Lightyear One in this Fully Charged video.

Should Self-Charging Be Banned?

In Norway (home of the EV, where over half of cars sold in 2020 were fully electric) they’ve banned adverts that reference “self-charging” believing the term is misleading.

I believe marketing a petrol car (100% powered by fossil fuels) as self-charging should be banned, as it’s extremely misleading. It makes polluting cars that burn fossil fuels seem cleaner and if you don’t do your research, you might think you’re doing your bit to look after the environment when actually, nothing could be further from the truth.

Ecosia 🌍

What is Ecosia?

Simply put, Ecosia is a search engine that plants trees with its profits.

💻📱 👉 💷💲 👉 🌱🌳

Which Search Engine Does Ecosia Use?

Ecosia is an organisation and search engine in its own right, but its results are powered by Microsoft Bing. Bing itself is carbon neutral and the whole of Microsoft are looking to go green by committing to be carbon negative by 2030.

How Green is Ecosia?

Ecosia recognise the impact the internet has on the environment of our planet. Ecosia runs on renewable energy, meaning your searches aren’t negatively impacting the planet.

“If the internet were a country it would rank #3 in the world in terms of electricity consumption” – Ecosia, 2018

In fact, searching with Ecosia is actually positively impacting the planet, with each search removing CO2 from the atmosphere. How? Because they plant trees with their profits.

As mentioned above, Bing (which powers Ecosia) is carbon neutral, so searching using Ecosia is a win-win from the perspective of your carbon footprint 👣

How Does Ecosia Make Money?

Like Google, Ecosia don’t make money from search results, they make their revenue from the ads that sit alongside the results.

Every time you click on an advert on Ecosia, you contribute to their revenue, which ultimately leads to trees being planted somewhere around the world

Ecosia tree tracker

They have a helpful counter on their search results to show you how many trees you’ve personally contributed towards.

So far they have planted over 100 million trees worldwide, supporting projects in 15 countries.

Why am I Promoting Ecosia?

The reason I wrote this article is because I think Ecosia awesome. They’re an organisation trying really hard to do the right thing and they’re clearly having an impact.

Congrats Ecosia on your success and thank you for what you’re doing for the world 🙏🎉🎊

Ecosia.org 🌍 give it a go 😊

Electric car cost per mile

Last time I looked at the difference in energy usage between petrol and electric cars. Another way of comparing EVs, hybrids and ICE cars is cost per mile. Using the Mini Cooper, we can compare all three. This example is based on UK units, assuming petrol is costs £1.30 per litre and electricity 14p/kWh – i.e charging at home.

Petrol

The petrol Mini Cooper S has a 44 litre fuel tank, and an average consumption of 44 miles per gallon – UK/Canadian mpg. A full tank of fuel can take the car 425 miles at a cost of £57.20, meaning each mile of driving costs 13.5 pence.

Hybrid

The Mini Countryman Cooper S plug-in hybrid has a 36 litre fuel tank and a 7.6kWh battery. Combined mpg figures range from 50.8mpg to 56.6mpg so we’ll use 53.4mpg for the comparison.

That means with a full tank and a full battery, you can travel around 423 miles – similar to the petrol car. The cost of 36 litres of petrol is £46.80 and 7.6kWh of electricity costs £1.06, making the total cost per mile around 11.3 pence.

Electric

The Mini Cooper Electric

The Mini Electric has a 32.6kWh battery and a range of 115 miles. It costs £4.56 to “fill up” the battery meaning each mile costs 4.0 pence.

Hybrid Inefficiencies

Interestingly, the hybrid is less efficient than the electric car when running on battery power and less efficient than the petrol car when running on the petrol engine. This is because it’s not just carrying an engine and a fuel tank, or a motor and a battery pack, it’s carrying all four all the time!

Hybrids were a great tool in the transition from ICE to EV, proving the concept and raising awareness. I believe they are no longer relevant however, as they’re significantly less efficient than their EV counterparts and don’t offer the electric range that people really need. The addition financial and efficiency costs don’t make hybrids worthwhile.

Most Efficient Car Pence Per Mile

The Hyundai Ioniq Electric

We’ve already established electric cars are far more efficient than petrol and hybrid-powered cars, so what’s the best of the best, the most efficient electric car? That title is shared by the Hyundai Ioniq Electric and the Tesla Model 3 Standard Range Plus which use just 240 watt-hours of juice per mile.

The Ioniq can drive an impressive 160 miles on a 38.3 kWh battery pack. It costs £5.36 to charge empty to full, at a cost per mile of 3.4 pence.

Just 3.4 pence for every mile of travel! That’s a quarter of the cost of the petrol Mini Cooper S!

The Model 3 can drive 195 miles (140 in winter, 275 in summer) on its 50 kWh battery pack. 50 kWh costs £7.00 on a £0.14/kWh home supply, which gives it a cost per mile of 3.6 pence. Worst case that’s 5.0 pence per mile in winter, best case it’s as low as 2.5 pence per mile in summer.

EV Tariffs

Some electricity providers now offer electric car tariffs, which make it even cheaper to charge. Some even pay you to take power off the grid when demand is low but supply is high!

£0.05/kWh is not uncommon. Charging a Model 3 at that price could give you 275 miles of range for £2.50.

0.9 pence per mile.

Petrol cars simply can’t compete with electric cars on pence per mile. EVs are too efficient 🙂