EV battery health explained: what SOH really means
SOH, capacity, range and warranty: what a battery health number means, what wears a battery faster, and what to check before you buy a used EV.
Read article →The short answer
Yes. Electric cars need servicing, but with no engine oil, spark plugs or timing belt there is less to do. A good EV service covers brake fluid, coolant, cabin filter, brakes (which can corrode from light use), tyres, suspension, the 12V battery, air conditioning and a check of battery health and software.
One of the attractions of an electric car is lower maintenance. That is true, but "lower" is not "none". An EV has fewer moving parts in its drivetrain, yet it still has brakes, tyres, suspension, fluids and electronics that wear and age. Skipping servicing altogether is a common mistake, and it can show up as a failed WOF or an expensive surprise.
What you do not need
- Engine oil and oil filter changes
- Spark plugs, fuel filters and timing belts
- Exhaust system servicing
- Clutch or conventional gearbox servicing on most models
What an EV service should cover
- Brake fluid. It absorbs moisture whatever type of car you drive, and is replaced on a schedule.
- Brakes. Regenerative braking does most of the slowing, so friction brakes get little use and can corrode, with calipers and slide pins seizing. A clean, free and lubricate service is common. See brakes.
- Reduction box oil. Most EVs have a sealed reduction gearbox whose oil is changed to the manufacturer's schedule.
- Coolant. Many EVs use coolant for the battery and power electronics, with a replacement interval.
- Cabin filter and air conditioning, which also work harder on some EVs to keep batteries cool.
- Tyres and alignment. EVs are heavy and torquey, and tend to wear tyres faster. See tyres and alignment.
- Suspension and steering, which carry the extra weight of the battery.
- The 12V battery. A weak one is the most common reason an EV will not wake up, even if the large battery is fine.
- Software and firmware, where updates are available.
- Battery health. A state-of-health reading, such as our AVILOO battery test, tells you how much capacity the pack has retained. See EV battery health explained.
How often?
Follow the manufacturer's schedule, which is commonly yearly or by distance. Even if your car has a long official interval, a yearly check of brakes, tyres, suspension, coolant and the 12V battery is cheap insurance, especially with WOF intervals getting longer for many vehicles from November 2026. See the WOF changes.
Hybrids are different again
A hybrid has a conventional engine and a high-voltage system, so it needs engine servicing and the EV-style checks. Its brakes can corrode from regenerative braking too. See EV and hybrid servicing.
Frequently asked questions
Is servicing an EV cheaper than a petrol car?
Often, because there is no oil, plug or belt work, but not always. Brakes, tyres, coolant, filters and the 12V battery still need attention, and EV tyres in particular can wear faster.
Why do EV brakes need servicing if they barely wear?
Because they corrode from lack of use. Regenerative braking does most of the work, so discs rust and calipers can seize, which is a common WOF failure on EVs and hybrids.
Does the big battery need servicing?
It is sealed and usually has no routine service items, but its health and cooling system are worth checking. A battery test such as AVILOO, which we offer for all makes and models of EV, shows how the pack is ageing.
Can I skip servicing my EV until the WOF?
It is not wise. A WOF is a pass-or-fail safety check, not maintenance. Servicing catches wear early and keeps the car reliable.
Written by the GVI Service Centre team. We are an independent workshop in Penrose, Auckland, servicing petrol, diesel, hybrid and electric vehicles. Facts about NZ rules are checked against NZTA and other official sources at the date shown; always confirm anything important with the source.
