hand holding an ev charger
MHEV and PHEV Hybrid Electric Vehicles If you're thinking about making the switch to a hybrid, it’ll be worthwhile to know the difference between a Mild Hybrid (MHEV) and a Plug-in Hybrid (PHEV).

What is a Mild Hybrid Electric Vehicle?

Mild hybrids, broadly speaking, are cars that that both a traditional internal combustion engine alongside an electric machine/generator. What this means is that the petrol/diesel part of the engine can be turned off at various points during a journey, such as when a car is stationary, but it can then restart really quickly. It can also augment the power of the traditional engine, but you can drive this vehicle as if it were a traditionally fuelled car.

The mild hybrid, as you might expect, takes the principles of a hybrid but utilises them in the mildest of ways. They typically have a small battery and an electric motor that can take over running the car’s ancillaries, such as the headlights and air conditioning.

This is particularly useful, because it means the engine can be turned off to save fuel at times when it is not needed, such as when decelerating or when stopped. The important distinction here, too, is that the wheels cannot be powered by the electric motor.

While it tends to mean the engine isn’t being used at times when it’s not being particularly inefficient anyway, the economy gains are fairly small. However, on the plus side, it’s the batteries that tend to add cost to hybrids, meaning mild hybrids tend to be less expensive to buy than other models.

white honda jazz on the road at night
peugeot 508 phev

What is a Plug-in Hybrid?

Plug-in hybrids are similar to the mild-hybrid vehicles mentioned above in that they switch between using the diesel/petrol engine and electric motor to improve efficiency. The difference is, unlike regular hybrids, plug-ins come with a higher-capacity battery and can be plugged-in to drive short distances on all-electric power. So, if you regularly make short trips and very rarely go on long adventures, this is a great way to keep your on-road activity free from fuel consumption.

Plug-in hybrids are the ultimate form of hybrid models, because, as you might have gathered, you can plug them into an external source of electricity to charge the batteries. This is great, because you can top the batteries up overnight and have a full charge when you head to work the next morning (or even at public fast chargers). This means you can maximise the electric-only range, and if your daily commute is quite short, you might find yourself rarely calling on petrol power, saving you lots of money in the long run.

If you don’t want to plug-in the hybrid you don’t have to. It will simply function as a regular hybrid.However, the downsides are that the charging technology tends to make PHEVs pricier than other hybrids. Meanwhile, if you have no means to charge the battery yourself, you might as well save that initial cash and go for a normal hybrid.

peugeot hybrid
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What is it like to drive a mild-hybrid car?


It's pretty much the same as driving a traditional car, te engine may stop more often because of the power supplied by the battery. And you can accelerate really quickly due to the electric charge provided.

How much of the car does the battery power?


The battery doesn't actually move the car forward, it simply helps make the car run more efficiently during certain functions such as the start/stop system.

Are mild hybrids exempt from tax?


Sadly not. Only zero emissions vehicles are exempt from tax.

Can I charge my plug-in hybrid vehicle in the rain?


Yes it's perfectly safe and has been tested, so you can have full confidence you are safe.

Is the PHEV battery covered by a warranty?


This is a matter for individual brands to decide, but Land Rover for example have given their EV batteries a six year warranty.

Can the National Grid handle all the demands for electricity?


Most of the charging goes on overnight when other demands are low, so the expectation is that there will be no problem with electricity demand.

Are MHEVs and PHEVs safe?


Yes. All new models of car and van have to comply with the same safety standards of every other vehicle.