VinFast EV: Is There Hidden Data on Battery Health After 100,000 Kilometres?

Kim Xuyen lives in Dong Nai province, roughly 1,200 kilometres from Hanoi in Vietnam. Her VinFast VF 5 EV has already passed 70,000 kilometres on the odometer. Asked how much battery capacity she has lost in that time, she says, 'It feels very little.' Within that single sentence lies both the strongest foundation and the deepest weakness of VinFast's current marketing strategy. When I track player fitness on a football pitch, I know that a single match's running distance cannot build an entire season's fitness profile. Similarly, the recently circulated VinFast article rests on the testimonies of three owners claiming their electric vehicles remain 'durable' and 'cheap' after 100,000 kilometres. What actually exists is a specific sample and a vague perception regarding battery health. VinFast is a Vietnamese electric vehicle manufacturer that listed on the US stock market in 2026. Its main models are the VF 5, VF 8, and VF 9. The three owners mentioned are Dinh Cong Thang of Hanoi with a VF 5, Kim Xuyen of Dong Nai with a VF 5, and Pham Van Mau of Ho Chi Minh City with a VF 8. Each has driven more than 70,000 to 100,000 kilometres. The three owners' accounts show that electric vehicles require no engine oil, oil filter, or spark plug replacements, reducing maintenance costs. One owner cites service costs of 300,000 to 400,000 Vietnamese dong. Another claims his costs are about one-quarter of a petrol car's. A third says he spent under 10 million dong over 1.5 years and more than 30,000 kilometres. These figures appear impressive at first glance. But when I look at the statistics, a major gap emerges. Every one of these numbers is an individual owner's estimate. There is no independent service invoice, no fleet-level data, no neutral study. Most importantly, only three owners testify—all satisfied, all connected to VinFast's promotional apparatus. Statisticians call this 'selection bias'. For electric vehicles, battery health—or State of Health (SoH)—is the most sensitive indicator. It measures what percentage of a new battery's capacity remains. What the VinFast promotional article says about this is not measured data—it is one owner's 'feels very little' type of personal perception. For a buyer, the most credible battery health information should be a percentage figure—such as '93% capacity after 50,000 kilometres'. But the article contains not a single specific number. I have followed a principle in sports analysis for many years: if a team refuses to publish post-match statistics, the statistics must be unfavourable. VinFast surely keeps battery health data internally—every modern EV has a battery management system recording every cell's voltage, temperature, and health. Yet it is absent from the promotion. Whether this absence is deliberate is a fair question. Similarly, the maintenance cost claim deserves reconsideration. A one-quarter petrol car cost is claimed, but which model, which year, which driving conditions—nothing is specified. In Bangladesh or India, we see a small petrol car's annual maintenance cost around 15,000 to 20,000 taka. In Vietnamese dong, that is roughly 4.5 to 6 million dong. By that measure, if VinFast's claim were true, costs would be 1.1 to 1.5 million dong annually—which does not match at all with one owner's under 10 million dong over 1.5 years. Reading the whole promotion, it feels like advertising wrapped in the guise of journalism. VinFast's core customer-acquisition barriers are two: will the car last, and will the battery die. This article targets exactly those two fears—and in both cases relies on personal perception. VinFast's strategy is not new. When it first entered the US market in 2026, it also ran testimonial-based promotions under a 'building trust' slogan. In 2026, as competition intensified in Vietnam, these promotions grew more aggressive. But real competition is not won with testimonials—it is won with neutral data. So if anyone truly wants to know how a VinFast EV performs after 100,000 kilometres, the right question is: where is the percentage figure for battery health? Where are the long-term fleet trial results? Where is the data from ten thousand owners? Until those answers arrive, the testimony of three satisfied owners is a promotional story—not proof. If VinFast publishes independent battery health test results within the next six months, a new market discussion will be born. If it does not, buyers will be forced to believe without proof—and that is the greatest risk of all.