Maintaining your EV

While there are some major differences between EVs (electric vehicles) and ICE (internal combustion engine) vehicles, they have much more in common than setting them apart.

After all, both are made to transport people, pets and packages around in comfort and safety. To do this they all have wheels, tyres, suspension, brakes, airbags, seatbelts – the list goes on.

The largest difference between the two is that an EV utilises battery packs and electric motors to drive, either solely or in tandem with an ICE depending on the type of EV.

This high-voltage electric powerhouse is the most crucial (and most importantly, expensive) part of an EV, so learning what there is to maintain (which is actually very little) is worth your time.

Ironically, it is HEVs (hybrid electric vehicles) and PHEVs (plug-in hybrid electric vehicles) that are the most complex to look after, as they involve both combustion engine and electric battery powertrains. BEVs (battery electric vehicles) have only an electric powertrain, which is much simpler than the system powering outdated gas guzzlers.

Key battery terms:

• Kilowatt Hours (kWh): The measurement of a battery’s energy capacity
• State of Health (SoH): How healthy a battery is, expressed as a percentage of current capacity compared to original capacity
• State of Charge (SoC): How full of energy your battery is, expressed as a percentage of full capacity

Maintaining your EV’s battery

Electric vehicles are powered by lithium-ion batteries, and in this regard they are much like the batteries in mobile phones and laptops.

However, they are managed by more sophisticated battery management systems (BMS) and, with a few exceptions, kept at optimal temperature with a liquid coolant. There are numerous misconceptions about how long EV batteries last– be assured they last far longer than the warranty.

As long as you remember a few key things, you can ensure your EV battery will live a long, healthy life. It's important to understand that lithium-ion batteries can degrade in various ways:

• Over time, batteries naturally degrade, regardless of usage - but much less than you may think;
• Fully charging or discharging the battery too often can lead to lithium plating, which slows down the flow of energy;
• Fast charging at high voltages can also cause lithium plating, especially in low temperatures;
• High temperatures can cause chemical reactions that harm the battery;
• Cold temperatures affect the mobility of lithium ions and impact battery performance and driving range.

Charging your EV for maximum battery life

Charging your battery in accordance with the manufacturer's recommendations is important to prolong an EV battery’s life.

Note: Some battery chemistries are best charged between 20-80% SoC. Others, in particular lithium-iron-phosphate (LFP), need to be charged to 100% at least once a week.

Ways you can look after your battery’s health include:

• If using DC fast chargers, it's best not to charge past 80% SoC. Not only does the last 20% take much longer to charge, but it’s also better for the battery to do a full charge, if necessary, on an AC or home charger;
• If your EV has a battery pre-conditioning function, using this on the way to a fast charger will ensure it is ready to receive all those electrons in the most efficient and healthy way possible;
• Don’t let your battery run too flat or charge up to full too often.

Keep your EV battery at its optimum temperature

Some – but not all – EVs use liquid cooling and battery management software to keep batteries at their optimum temperature during very hot or cold weather, and when driving.

Just like in conventional ICE vehicles, this coolant can degrade over time, reducing its ability to transfer heat and keep components cool. If your EV is water-cooled, ensure this fluid is checked regularly if it is listed in the maintenance schedule.

However, some manufacturers such as Tesla state that most of the time the battery coolant will not need replacement for the life of the vehicle.

Ways to look after your EV battery’s temperature include:

• Avoiding heavy, fast acceleration (to limit discharge) and using lower kW output chargers where possible (to limit charge) will also help keep batteries happy;
• Parking your EV in the shade or under cover, when possible, can also save the battery from heating up under Australia’s sun (and helps save energy used by the car cooling the battery while in the sun);
• On very cold days, it’s also a good idea to pre-condition the battery before driving.

What else can I do to maintain my EV?

The cost to maintain and service an EV is often less than that of an ICE vehicle. However, when the electric motor and battery are taken out of the equation, an electric and ICE vehicle are almost identical and their servicing should be approached in the same way. 

Both types of car use suspension, steering and braking components, tyres, fluids, wiper blades and even a normal 12-volt lead acid battery, and all wear out over time and need replacing. Maintaining the correct tyre pressure as specified in your owner's manual will improve fuel economy.

Other ways to help maintain your EV are:

• Maintaining the correct tyre pressure as specified in your owner's manual will improve energy efficiency and maximise driving range;
• Have your EV serviced as per the manufacturer's service schedule.

The NRMA is here to help with roadside assistance in the event of a breakdown and motoring advice all year round. You can contact us to upgrade your membership to include roadside. 

DIYers and mechanics who are not high-voltage certified should never attempt to service any part of the high-voltage system on an EV.