How do hybrid cars charge?

You may know that a hybrid car contains both a conventional internal combustion engine (ICE) and also an electric battery, and that the two together power the vehicle’s drivetrain.

So far, so good. But how does the hybrid vehicle’s battery recharge? Most hybrid electric vehicles (HEVs) don’t have a charging port and cannot be plugged into the mains electricity supply, or into an electric car charging post.

If the battery is charged only by the combustion engine, how does that offer better efficiency than just running the car directly from the ICE? In this article we’ll take a look at where a hybrid vehicle battery gets its charge from, and why this is better than a pure-ICE vehicle.

Self-Charging Vs. Plug-In HEVs

First of all, it’s important to note that some HEVs do have a charging cable. These are called Plug-in Hybrid Electric Vehicles, or PHEVs.

PHEVs can normally drive further in fully electric mode, and can be charged from the mains electricity supply or a compatible EV charging post; however, they are relatively uncommon among hybrid vehicles overall.

‘Self-charging HEVs’ are those with no mains connection. These include mild hybrids (MHEVs) and full hybrids (FHEVs). The battery gets all of its charge from the vehicle’s ICE and from its motion while driving.

This is an important distinction between the two. MHEVs and FHEVs are dominated by their combustion engines – the electric battery acts as more of a boost than as a full alternative power source. In contrast, PHEVs can drive reasonable distances without using any fossil fuels at all.

Charging From The Ice

Self-charging from the vehicle’s ICE is a relatively straightforward process. It works in much the same way as a conventional vehicle’s 12-volt battery recharges during driving. The only real difference is that the battery being charged is much bigger.

Recharging by burning petrol or diesel is obviously a problem for a hybrid vehicle’s emissions, so how does this help?

The answer is about using the combustion engine at a steadier rate. Under hard acceleration, some of the horsepower comes from the electric battery, so the ICE can operate more efficiently with fewer harmful emissions.

Once the acceleration is complete and the ICE is operating well within its capacity, some of that combustion energy can go into replenishing the electric battery, resulting in better fuel economy and lower emissions overall.

Charging From Kinetic Energy

Most HEVs do have a way to charge the onboard battery without using the combustion engine, and that is via kinetic energy retrieval during braking.

In short, the energy of the movement of the vehicle’s wheels can be recovered as the vehicle slows down, and transferred back into the electric battery. It’s a technology made famous by Formula 1 motor racing’s KERS (Kinetic Energy Recovery System) in 2009.

Recharging the battery under braking allows the vehicle to be powered with less fossil fuel, using energy that would normally be lost to the environment or as heat in the brake pads.

These two methods – the combustion engine and the energy recovered during braking – are the two major ways in which all HEVs recharge, with the addition of mains power for PHEVs.

How To Use More Kinetic Energy

It’s quite clear that the more your vehicle recharges from kinetic energy – and the less it uses fossil fuels – the better your fuel economy will be and the lower your exhaust emissions will be.

Luckily the best practice for driving HEVs is broadly the same as it has always been for conventional ICE cars: keep acceleration steady, maintain a constant speed, and don’t put too much strain on the engine.

By doing this, you maximise your fuel economy and minimise your emissions. By braking steadily, you can also make sure your car is able to transfer as much of that energy as possible back into its battery.

The result is good news for the environment, for the range of your vehicle, and for your wallet as you’ll use more energy recovered from the environment, which is essentially free compared to petrol or diesel.

Want To Know More?

If you would like to know more about the top hybrid cars and hybrid models, what’s on the market and what’s available to lease, either as a personal lease or as a business lease, , please contact Synergy today and speak to a member of our friendly and professional team.

We are always happy to discuss the vehicles we have available, as stock deals or factory orders, and help you to choose one that’s right for you, and that includes making sure you understand the technology that goes into a hybrid electric vehicle.