The Electric MOT

Tesla X100D

The electric vehicle revolution speeds up  

The electric car market is growing quickly, with more than 245,000 pure-electric cars (HEVs) on UK roads at the end of April 2021, and over 515,000 plug-in models if including plug-in hybrids (PHEVs)

The chart below shows the number of electric cars registered in the UK – as of the end of April 2021 there were more than 515,000 plug-in vehicles with approx. 245,000 battery-electric vehicles (BEVs) and 270,000 PHEVs registered. Last year saw the biggest annual increase in number of registrations, with more than 175,000 electric vehicles registered, showing a growth of 66% on 2019. Last year, despite the coronavirus impact, the chart shows that 2020 was a huge growth year for plug-in vehicles. 

Graph showing cumulative number of plug-in vehicles registered in the UK

Where to charge?

With new charge points being added daily, the UK’s charging point infrastructure is continually changing. The chart below shows the breakdown of charge point devices by slow (3-5kW), fast (7-22kW), rapid (25-99kW) and ultra-rapid (100kW+) power rating for the past five years and 2021 to date.

Graph showing number of public charging points by speed - 2016 to 2021

Electric vehicles and the MOT

What do the letters mean?
All-Electric Vehicles (EVs, BEVs)
EVs, also called battery electric vehicles, have a battery that is charged by plugging the vehicle in to charging equipment. EVs always operate in all-electric mode and have typical driving ranges from 150 to 300 miles.
Hybrid Electric Vehicles (HEVs)
HEVs are powered by an internal combustion engine and an electric motor that uses energy stored in a battery. The vehicle is fuelled with petrol or diesel to operate the internal combustion engine, and the battery is charged through regenerative braking, not by plugging in.
Plug-In Hybrid Electric Vehicles (PHEVs)
PHEVs are powered by an internal combustion engine and an electric motor that uses energy stored in a battery. PHEVs can operate in all-electric (or charge-depleting) mode. To enable operation in all-electric mode, PHEVs require a larger battery, which can be plugged in to an electric power source to charge. To support a driver’s typical daily travel needs, most PHEVs can travel between 20 and 40 miles on electricity alone, and then will operate solely on normal fuel, similar to a conventional hybrid.

The MOT Test is primarily a test of a vehicle’s roadworthiness on a given day – that the vehicle is safe, for both the driver and passengers in the vehicle as well as other road users, to be driven on public roads, in terms of braking, steering, bodywork, safety systems and emissions. Additionally, there’s a secondary function of ensuring that number plates comply with regulations, so that vehicles can be reliably identified for enforcement purposes by number plate recognition (ANPR) cameras.

With the obvious exception of ‘emissions’, pretty much everything else on an electric vehicle is subject to the same MOT safety checks as a regular internal combustion engine (ICE) vehicle.

There are some differences however. Electrically powered vehicles are not subjected to an MOT emissions check – even if the vehicle is a hybrid, and has either a diesel or petrol engine under the bonnet somewhere – if there’s an electric motor fitted which provides power to the road wheels, then the vehicle is exempt from an emissions check during an MOT inspection.

However, if the vehicle leaks oil or fuel from an auxiliary motor that make a pool 75mm or greater in five minutes, regardless of the engine running or not, it should fail the MOT.

If a hybrid vehicle is presented for the MOT Test with the auxiliary motor running, leaks or excessive noise from the auxiliary engine exhaust would cause a ‘fail’.

Reduced brake wear

In one way, albeit indirectly, electric vehicles will have an effect on the MOT failure rate. Because they use so-called ‘regenerative braking’, which uses some of the energy used in braking to recharge the battery, this should have the effect of reducing wear on the brake pads and brake discs, resulting in electric cars’ brakes lasting longer before the wear becomes an MOT failure. An incidental factor, but something to consider. 

Battery safety

The batteries in modern cars carry a lot of energy – think about it: 50 litres or so of petrol carried by cars has about the same energy as those fully charged batteries in electric cars – and a petrol explosion is a very dangerous event. So too, if there’s a problem with those multiple battery packs in electric cars – whilst every precaution is taken, it is not unknown for batteries using the same technology to spontaneously ignite. So maybe they should be checked during an MOT inspection. Well, they are supposed to be checked visually during the MOT Test – but it’s not that simple. Here’s what the MOT Manual, which MOT Testers must follow precisely, has to say on the subject:

“You must inspect the battery(ies) on all vehicles including electric and hybrid vehicles. The check does not apply to Class 3 vehicles.

Batteries used for propulsion of electric or hybrid electric vehicles carry high voltage and additional care should be taken when testing them.

The propulsion batteries are unlikely to be accessible, but if they are they should be assessed visually only. If the batteries are leaking, you should refuse to test the vehicle using Item 4 reason ‘h’ of the Introduction section.

You should also be mindful of high voltage components and cabling as these may be capable of delivering a fatal electric shock.”

Note that is says, “The propulsion batteries are unlikely to be accessible”, So Testers aren’t likely to be able to tell whether or not the propulsion batteries are leaking – it’s just a very cursory inspection.

Those are the main differences, but here’s a list of all the main headings under which MOT Tests are carried out, comparing a normal vehicle to an electric vehicle.

Change chart

0. Identification of the vehicle 

This includes the number plates, as well as the Vehicle Identification Number (VIN).

The rules here apply identically to both electric and normal vehicles.

1. Brakes

Brake condition and operation, service brakes, secondary brakes, parking brakes, anti-lock braking system (ABS), electronic braking system (EBS) and brake fluid rules and inspection for car and passenger vehicle MOT Tests.

No change here either – but as noted above, brake wear will be reduced because regenerative braking on electrically powered vehicles will mean that the brake pads will be used less.

2. Steering

Mechanical condition, steering wheel and column or handlebar, forks and yokes, steering play and electronic power steering (EPS) rules and inspection for car and passenger vehicle MOT tests.

No change – the mechanical and electronic steering systems of electric vehicles are identical to normal vehicles.

3. Visibility

Field of vision, bonnet catches, condition of the glass, the view to the rear, windscreen wipers and windscreen washer rules and inspection for car and passenger vehicle MOT Tests.

No change here either, anything which affects the driver’s view of the road is subject to the MOT Test.

Why is the bonnet catch included here? If the bonnet flies up while driving because of a faulty catch, that would certainly affect the driver’s view of the road. The same applies to the front storage area of an electric vehicle.

4. Lamps, reflectors and electrical equipment

Headlamp, position lamps, daytime running lamps, stop lamps, indicators, hazard warning lamps, fog lamps, reversing lamps, lighting ‘tell-tales’, trailer electrical socket, electrical wiring and battery rules and inspection for car and passenger vehicle MOT tests.

A slight change: In theory the Tester will check the wiring for the electrical drive system, but will be constrained by both safety (high voltage), and constraints regarding what can be inspected visually without any dismantling of components.

5. Axles, wheels, tyres and suspension

Axle, wheel bearing, wheel and tyres, tyre pressure monitoring system (TPMS), and suspension (including springs, shock absorbers, and suspension arms and joints) rules and inspection for car and passenger vehicle MOT tests.

Electric vehicle systems are largely identical to conventional vehicle systems, so no change here.

6. Body, structure and attachments

Structure and attachments (including exhaust system and bumpers), and body and interior (including doors and catches, seats and floor) rules and inspection for car and passenger vehicle MOT tests.

No change – unless the drive battery can be inspected for its security

7. Other equipment

Seat belts and restraint systems, airbags, anti-theft devices, horn, speedometer, speed limiter and electronic stability control (ESC) rules and inspection for car and passenger vehicle MOT tests.

All pretty much identical for both normal and electric vehicles.

8. Nuisance (including exhaust emissions)

Noise, exhaust emissions, engine malfunction indicator lamp (MIL) (sometimes called an engine management light or ‘EML’), and fluid leak rules and inspection for car and passenger vehicle MOT tests.

Change: The engine management light is not applicable*, as noted above, if the vehicle, of whatever type (eg plug-in electric, hybrid etc.) has a battery driving the road wheels an exhaust emissions test will not apply. 

However, excessive oil leaking from an auxiliary motor will cause the vehicle to fail.

*Battery vehicles do not have the equivalent of an MIL or an internationally agreed and recognised battery warning system, so they are not as yet an MOT Testable item.

In Conclusion

When it comes to the MOT Test, whilst Testers have to take more care and be aware of potentially dangerous electrical hazards during their inspection of electric cars, from the vehicle owner’s perspective there’s no need to worry about emission failures on any vehicles with electrical power delivered to the wheels, because the emissions aren’t checked. 

Also, whilst the main drive batteries are supposed to be inspected by MOT Testers (and with great care regarding high voltage hazards), it is very unlikely that Testers would find any defect as most of the system is hidden from view, and a golden rule during an MOT inspection is that nothing should be dismantled.

It appears that the main change to the MOT Test from the MOT Testing Station’s point of view will be that the extremely sophisticated emissions testing equipment they have all been forced to buy to perform increasingly stringent MOT emissions tests will be left largely unused as more UK drivers turn to electrically powered vehicles.

In environmental terms at least, that’s probably a good thing!

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