First, it’s important to note that the Austrian startup Aviloo generates its revenue by using its proprietary Aviloo Flash Test to determine the State of Health (SoH) of electric vehicle batteries. The company collaborates with car dealerships, professional used car dealers, and leasing companies, which conduct these tests via the OBD interface of the EVs. The result is a manufacturer-independent State of Health for each vehicle – and this is particularly relevant for used cars.

According to Aviloo, vehicles’ built-in battery condition displays are often unreliable. While buyers of internal combustion engine cars primarily focus on age and mileage, the condition of the traction battery is especially critical for electric vehicles. This is because every EV is affected by degradation; an ageing process that leads to a permanent loss of storage capacity and, consequently, range. Most manufacturers today guarantee that an EV will retain at least 70 per cent of its original battery capacity after eight years or 160,000 km. This sets a benchmark against which used electric vehicles must be measured.

With this in mind: for its new ‘Aviloo Certified EV Battery Report’, which will be published semi-annually in the future, Aviloo has analysed data from over 500,000 used EVs. These were tested using the independent Aviloo Flash Test worldwide, so that different climate zones could also be accounted for. The analysis focused on 20 particularly common EV models, for which the report specifies the median battery condition at three mileage levels: 50,000 km, 100,000 km, and 150,000 km.

Comparing the three mileage levels reveals three clear patterns, as Aviloo states: First, the median battery health decreases with increasing mileage – which is hardly surprising, as wear and tear naturally increases with distance travelled. Second, the differences between individual vehicles grow with mileage; degradation is real and increases with the distance covered. Equally important is the third pattern: the differences between models remain consistent across all three mileage levels.

Looking at the model ranking, 16 out of the 20 EV models examined still have a median State of Health of at least 90 per cent after 150,000 km, while the remaining four models fall within the 85 to 90 per cent range. This means that all 20 models, even at the typical warranty limit of 160,000 km, still have a median State of Health well above the warranty-relevant 70 per cent – specifically between 80 and 90 per cent.

However, it is important to note that the average obscures the fact that there are significant outliers – both high and low – for every model analysed. For example, the Aviloo database shows that the Hyundai Ioniq 5 (72.6 kWh) has an average SoH of 92.8 per cent after 150,000 km, corresponding to a range of around 319 km. Yet, the spread between individual vehicles of this model at 150,000 km mileage is over 12 per cent SoH, which translates to a range difference of around 42 km.

Marcus Berger, CEO of AVILOO, says: “The truth in this data is that averages hide a lot. Yes, EV batteries are ageing better than the ‘they wear out fast’ myth suggests – but that’s not the most useful thing this report tells you. What matters is that battery health varies significantly between models, and even more between individual cars of the same model. A gap of ten or fifteen percent in state of health is a real difference in range, in what a car is worth, and in what you can rely on it for. You simply can’t know where your car sits in that range without testing it independently.”

Berger’s recommendation is therefore clear: he believes that anyone buying a used EV should have an Aviloo Flash Test performed beforehand to determine the battery health—that is, the actual remaining capacity of the battery.

aviloo.com (PDF)