Electric Vehicle Servicing
Electric Vehicle Servicing
Electric cars have their supporters and detractors but whatever the politics and practical effects of EVs, most people seem to agree that “fewer things can go wrong” with electric motors compared to Internal combustion engine (ICE) driven vehicles. Considering that EVs are (like-for-like) more expensive and that most people also want a charging station and electricity prices are rising, it is good to know that at least servicing costs will fall – probably.
So, you will be pleased to hear that we agree in general terms with that assessment: EVs should need fewer parts replaced over the lifetime of the vehicle and garages should be able to service more cars in the same amount of time.
Which parts of an EV should not need servicing?
For many drivers considering an EV, this might be the more important question. The battery cells in an EV should last for a good long time, perhaps in the future for the lifetime of the vehicle. The early evidence for most models (certainly most newer ones) seems to confirm this. Unless there is a physical impact, a fire or a chronic electrical problem with the battery itself, most EVs will rarely require a repair or a replacement until very high mileage / number of associated recharge cycles is reached. The most likely cause of premature damage to the battery is the frequent use of highway fast charging stations or cheap home chargers.
Regardless as to which battery technology you use, the cells always deteriorate over time and as they do, an EV’s performance potential drops off as well. Most models have on-board technology that keeps the apparent performance steadier over time but if you do want your acceleration restored, batteries can be opened, and individual cells replaced. It depends a lot on the model you have, and the operation does not come cheap. Absolutely never attempt a battery overhaul at home – they are dangerous!
If the battery does fail before you want to part with the rest of the vehicle, in the future your best option may be a second-user or refurbished battery. This market is in its infancy now.
The other main component that should almost never require repair or service are the motors. These too appear to be highly reliable, and those in smaller cars have so far proven more reliable than their counterparts in executive and performance cars.
Which parts of an EV do need servicing?
An EV lacks an exhaust system, fuel filter, carburettor, spark plugs and any other of the components associated with servicing combustion engines. However, almost every other component present in an EV is much the same as those in any other kind of car – the steering, suspension, tyres, lights, brakes and so forth. All these items wear out eventually and should be routinely inspected, serviced, repaired or replaced as necessary.
The bad news for EV drivers is that their vehicles are heavier than equivalent petrol or diesel driven vehicles. That increased weight takes a toll on many of these components. There is plenty of evidence that EVs suffer faster tyre and brake wear and are more likely to need attention to their steering and suspension at an earlier date. To avoid breakdowns, expensive repairs or even an accident, regular servicing of these systems in an EV is essential.
There is a danger that EV drivers are being lulled into complacency about the condition of their vehicle by all the talk of improved reliability. The result is likely to be an increased number of avoidable repairs and breakdowns. Steering and suspension damage are not the cheapest of problems to rectify. We therefore recommend that EV drivers make service inspections a regular routine because the amount of money that can be saved by keeping the vehicle tuned is considerable. For example, if you develop a loose coupling in the steering and it is not identified early it will lead to increased wear in other connected components.
The other disadvantages of EVs are some components that are not present on petrol and diesel driven vehicles. That mostly means electrical components but most EVs have regenerative braking too.
These extra electrical parts can be divided into two broad categories. The first is the cables, terminals, high voltage relays, HV inverters, charging sockets and junctions that service the battery array and link it to the motor. These should be examined often, especially for any evidence of over-heating or corrosion. The battery’s coolants are also very important.
The second is all the sensors, relays, harnesses and software that control the many advanced digital systems that are installed into most modern electric vehicles (adaptive cruise control, anti-lock braking, proximity sensors and so forth). These components are easily damaged and frequently need to be tested, adjusted and recalibrated. As far too many motorists have discovered the hard way, just swapping your car radio can leave you in need of a full computer reinstallation in some modern vehicles.
Regenerative braking is a great way to make vehicles greener and to extend an EV’s mileage per charge. Essentially, instead of just using the brakes – which wastes all the energy in the forward momentum of the car (and creates frictional wear in the process) – an EV slows itself down by using the motor and the resulting electromagnetic flux transfers kinetic energy back into stored electricity. The basic technology is far from new – a version of it was in use in 1886 (no that’s not a misprint) by the Sprague Electric Railway & Motor Company.
Modern versions are considerably more sophisticated and depend on a good deal of fine tuning to work safely and efficiently. The precise point at which regenerative braking cuts in or out is important for the vehicle’s safety and fuel efficiency. When regenerative braking is working at its best, it takes pressure off your brakes – which is very important in heavy electric vehicles. It also brings you to a more optimal halt – reducing tyre wear.
The fact that there are fewer parts to service does not mean the length of time between services should be longer. In fact, the extra strain on your tyres, brakes and suspension should encourage you to have more checks rather than less. The good news is that they will take less time and cost you less.
Not all your service attention needs to be a “full service”. Checks on these common problem areas are much easier to conduct than a thorough investigation and an interim-level service will do the job. We also recommend that you take advantage of the many free checks available at garages in our network.
Occasionally you should also have a full service that includes a computer interrogation. The computer read out can provide warnings about any firmware or sensor problems as well as issues in the drive train. It also provides a check of the battery performance and can identify how each cell inside the battery is holding up. Some fail earlier than others and, depending on the type of battery, it is sometimes beneficial to replace a faulty cell so that it does not place extra strain on neighbouring cells. Over time, a history of diagnostic readouts allows your service engineer to identify where any weaknesses are developing and predict how long it will be before an intervention is needed. This information is reassuring and allows you to budget for any future work in advance.
EV manufacturers usually suggest an interval between (full) services for each car model. The recommendation may be in months or in miles or both - in which case it is whichever comes first. For example, the suggested interval for the Renault Zoe is 18,000 miles and for the Vauxhall Corsa-e it is 16,000, but for the Kia E-Niro it is just 10,000 miles – so the difference between one EV and another can be substantial. Most seem to suggest 2-year intervals between full services if you do not exceed those mileages. However, we suggest at least one additional interim service, especially after the vehicle is four years old
What does an EV service include?
As we mentioned above, the mechanical (as opposed to engine) checks are much the same for both EV and combustion engine cars. Incidentally, there are also very few differences for MOT purposes, because MOTs are primarily mechanical safety checks anyway – not checks on the reliability of the engine or drivetrain. Just as with combustion engine cars, it makes very good sense to have a full service immediately before a MOT to ensure a pass. It is just as easy to fail a test in an EV because of a faulty wiper blade, loose steering column, empty windscreen washer or misaligned headlight.
Suspension and steering are the most likely major things that could need attention. These really are a case of “a stitch in time saves nine”. Neglecting a minor fault in these systems leads to needlessly expensive repairs later. Adjustments are part of the service.
As you can imagine, most of the additional checks performed in an EV service are electrical but there will be close attention paid to the charging point and cable, the high voltage cables and connectors and a full diagnostic of the on-board computer. EVs have a cooling system to keep the main battery at a safe and efficient temperature. An EV service includes an inspection of the fluid level and a top up if needed. Note that EV battery cooling systems are usually sealed and should only be checked by an EV-trained engineer.
Your EV almost always has a separate 12volt battery that supports the car’s non-drive related electricity usage (lights, radio, electronics). This will also be checked for you. They need to be replaced just as often as those in conventional vehicles.
What is not included in a full service?
By definition, a service does not include the cost of any spare parts you are found to require. However, the parts of an EV that are most expensive to strip down, and repair are the ones least likely to go wrong – the main batteries, the motor or motors and the differential. Common parts that do often need replacing include the 12v battery, the tyres, the wipers, the brake fluid, the cabin air filter and other air conditioning components.
Because electric vehicles are heavier, tyres are prone to wear faster. If you develop a suspension or steering issue that is not caught early, it will likely reduce the lifespan of your tyres even more by changing the pattern of wear. The extra torque provided by an electric motor can also take its toll if you are not a careful driver.
EV and hybrid vehicles are more demanding on their tyres than conventional vehicles, so many tyre manufacturers have developed tyre ranges specifically for them. They offer a lot of advantages, but they are also more expensive – so service attention to maximise their lifespan is very important.
Just as on conventional cars, the front and rear wheels on EVs typically wear at a different rate. Many EV drivers like to equalise their tyre wear by having their tyres rotated annually or six-monthly. In other words, the rear wheels are swapped to the front and vice versa. You can book a tyre rotation to coincide with your service if you wish.
Where should I get an EV service?
Always use an approved garage with properly trained EV specialists. This is for two reasons; first because the electrical dangers inside an EV require the engineer to be licensed to work on them, and secondly because it could invalidate your EV warranty if they fit anything that is not original equipment on that model. For that reason, if your car is in warranty and you are ever offered cheaper second-hand or generic components, you should refuse them.
We can direct you to the nearest garage in our network with suitably trained personnel and equipment. You can rest assured they are fully trained and will only fit the original manufacturer’s equipment to your EV.
About your EV tyres
EV tyres must cope with the increased weight of the battery banks and the high acceleration (torque) of electric motors. They therefore have numerous differences that are not always visible to the human eye, for example sidewall reinforcement. Another important design consideration is that electric motors are a lot quieter than engines so if you drive on conventional tyres you will become very conscious of the rolling noise from your tyres. This is irritating and distracting to most drivers and diminishes your ability to hear other noises around you - which is one of the potential safety advantages of an EV.
EV tyres are also redesigned for environmental reasons - after all, that is the primary motivation for developing the new electromotive technologies that make an EV possible. Making EV tyres higher and narrower than most conventional tyres helps them respond quickly to acceleration and reduces the energy lost to road drag. As a result, you get more mileage per charge when you are running on proper EV tyres - which reduces your carbon footprint. It also reduces more of that road noise - another environmental benefit of EVs. Most EVs now run on traditional looking car tyres, so the idea of tall and thin tyres is only relevant to a very small number of cars, the main one being a BMW I3.
Maintaining high grip without road noise under extra weight is quite a challenge for both the tyre and vehicle designer, so genuine EV tyres borrow a lot of technology from premium tyres. That tends to push up their cost but that should not tempt you to settle for a cheaper alternative unless the specifications are a very good match (which is not likely).
The performance and efficiency specifications of electric vehicles are achieved by the car and tyre manufacturer working closely together. Consequently, although non-EV motorists are often encouraged to ‘shop around’ for alternative tyres, we would rarely give this advice to an EV owner. In most cases you should replace a worn tyre set with another set of the same, or very well matched, tyres. If you are considering it, don’t be shy to ask the fitter for advice.
Tyres that are designed for a specific vehicle (whether an EV or a conventional high-performance vehicle) are often given a mark that identifies the car brand - for example, “AO” denotes tyres intended for Audis, a star often denotes tyres intended for BMW. This is something to look for, but it is more important to make sure the load bearing mark matches your original tyres or those specified in your handbook. As we’ve covered, the extra weight of an EV means they should be ridden on XL or even HL tyres - which have extra sidewall reinforcement. Your fitter will always be happy to discuss the benefits or potential disadvantages of your tyre choice. Be aware that riding on tyres unsuitable for an EV could affect your insurance cover.