What are the differences between Full Hybrids, Micro Hybrids and Mild Hybrids

What are the differences between Full Hybrids, Micro Hybrids and Mild Hybrids?

Picture of the Lexus GS450h which is a Full Hybrid car, capable of running in EV (Electric Vehicle) Mode only

Picture of the Lexus GS450h which is a Full Hybrid car, capable of running in EV (Electric Vehicle) Mode only. Picture courtesy of www.lexus.co.uk

There seems to be a bit of confusion when the term Hybrid is used in the context of cars. Just to add to the mix, new terms such as Micro Hybrids, Mild Hybrids and Full Hybrids have surfaced in recent times as car companies try to introduce their flavor of ‘hybrid’ cars. There are very large technical differences between these types of Hybrids and if you don’t know what the differences are or what benefits each offers, you could be disappointed when you buy your next car.

What is a Full Hybrid?

A Full Hybrid is a vehicle that has an Electric Motor (which can also act as a generator) and an ICE (Internal Combustion Engine) such as a petrol or diesel engine. The vehicle can be propelled on the Electric Motor without the need for the ICE to be running, known as EV (Electric Vehicle) Mode. For example, in the Lexus Hybrid range of cars, there is an EV Mode button so the driver can activate EV Mode. When not in EV Mode, the Electric Motor will assist the ICE when it is accelerating, resulting in quicker acceleration over a wide range of vehicle speeds. Also, the Electric Motor is used for regenerative braking when the vehicle decelerates or brakes and charges the batteries when required.

The benefits of Full Hybrids are:

  • no fuel is burned whilst the car is standing, thanks to ‘stop-start’ system;
  • better braking due to regenerative braking which helps with stopping the car and reduces brake pad and disc wear;
  • Internal Combustion Engine gets power boost during acceleration;
  • can drive car or vehicle in Electric Vehicle Only mode without needing the Internal Combustion Engine to be operating, which means no noise, no tail pipe emissions whilst in EV mode and significant fuel savings.

What is a Mild Hybrid?

A Mild Hybrid is a vehicle with a small Electric Motor (which can also act as a generator) and an ICE (Internal Combustion Engine). The Electric Motor (acting as a generator) is used for regenerative braking and to charge the batteries when required. Unlike a Full Hybrid, a Mild Hybrid often cannot move on the Electric Motor alone as the Electric Motors are often too weak. To move the vehicle, the ICE needs to be operating. The Electric Motor is used to start the ICE and it may assist the ICE when accelerating. Often, a ‘stop-start’ feature is included so that when the vehicle stops for example at a red light, the ICE will automatically switch off and when the driver presses the accelerator, the Electric Motor will automatically start the ICE and assist with acceleration.

The benefits of Mild Hybrids are:

  • you don’t burn fuel whilst standing thanks to ‘stop-start’ system;
  • better braking due to regenerative braking which helps with stopping the car and reduces brake pad and disc wear;
  • Internal Combustion Engine may get some power boost during acceleration (if it is a parallel hybrid).

What is a Micro Hybrid?

A Micro Hybrid is a type of vehicle that has an ICE (Internal Combustion Engine) and  an alternator (which can also start the ICE) which is used for ‘stop-start’ purposes. In my opinion, this is not a real hybrid. The alternator is not capable of moving the vehicle on its own. The vehicle cannot drive from the battery. As a result, for the vehicle to move, it requires the ICE to be running. The way it works is when the vehicle comes to a stop like at a red light, the ICE will stop automatically. During the deceleration process just prior to stopping, some energy may be recovered to charge the battery, but not very much. When the accelerator is pressed, the alternator instantly restarts the ICE.

The only benefit of Micro Hybrids is that you don’t burn fuel when you are standing, thanks to the ‘stop-start’ system.

Why are Full Hybrids better than Mild Hybrids or Micro Hybrids?

Full Hybrids are better than Mild Hybrids or Micro Hybrids because a Full Hybrid can do everything a Mild Hybrid or Micro Hybrid can plus more. The vehicle or car can run in the following modes:

  • Electric Motor only known as EV (Electric Vehicle) Mode;
  • ICE (Internal Combustion Engine) only; or
  • both with the Electric Motor and ICE.

Mild Hybrids and Micro Hybrids will always need the ICE to be running which means you never get the EV Mode. There is no EV Mode button like in the Lexus Hybrids. It means whenever you are driving (cruising or accelerating), you are burning fuel. A Mild Hybrid has a comparatively small Electric Motor compared to a Full Hybrid. A Full Hybrid saves more fuel than an equivalent (in size and power) Mild Hybrid.

The benefits of having an EV Mode are:

  • Enormous fuel savings compared to Mild Hybrid, Micro Hybrid or non Hybrid vehicles;
  • Can drive from the battery pack without needing the ICE to be running;
  • Can drive silently with no tail pipe emissions until the battery pack needs recharging. This is handy in under ground car parks or when driving near places where you want to be silent like near hospitals.

Why are Mild Hybrids and Micro Hybrids appearing on the market when Full Hybrids are better?

Mild Hybrids and Micro Hybrids are appearing on the market because it is a relative cheap and simple engineering exercise to include these features in cars. With Micro Hybrids, it is as simple as retro fitting an alternator (with starting capabilities) and connecting a small controller to enable the ‘stop-start’ feature. In some jurisdictions, governments may provide incentives for buying hybrids and to qualify for the incentives, Mild Hybrids and Micro Hybrids may also qualify along with Full Hybrids. Full Hybrids need to be properly engineered and not many car companies have the experience or expertise to build a Full Hybrid car. Lexus is one of the few car companies in the world that has years of experience in building Full Hybrid cars.

What to look for when buying a hybrid car?

When buying a hybrid car or vehicle, you want to ensure at the very least that it has the following features:

  • ‘Stop-Start’ system so that car does not burn fuel when you are not moving;
  • Ability to drive on batteries alone at speeds of at least 28mph (45km/h), known as EV (Electric Vehicle) Mode. This will ensure that you can drive a short distance without having the ICE (Internal Combustion Engine) running which is handy when driving in residential areas or near hospitals;
  • Regenerative braking so that whilst you are decelerating or braking, you can recover some of the braking energy which can be used to recharge the battery pack. Regenerative braking also helps save on brake pad and rotor wear which cuts your maintenance costs. Also, during the braking process, you want the ICE (Internal Combustion Engine) to cut off automatically, which saves you even more in fuel costs.
  • Electric Motor to assist during acceleration as this helps cut fuel usage and costs. This acceleration can be from a standing start or when overtaking a car on the highway.
  • Power boost from the Electric Motor which means more power whilst burning less fuel.

All of the above mentioned features are only found in Full Hybrid cars. Micro Hybrids or Mild Hybrids only have a fraction of the above features. If you want to enjoy the benefits of the above mentioned features, then in my opinion, look for Full Hybrid cars. Lexus – Creating Amazing cars is what they do best and they are one of the market leaders in creating Full Hybrid cars. Their range of Full Hybrids are definitely worth considering.

This is Crazy Al signing out.

One Response to What are the differences between Full Hybrids, Micro Hybrids and Mild Hybrids

  1. Karl says:

    looks like Lexus really leading the way in Hybrid development.

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