What is the VinFast VF8 Charging Time Calculator?
This tool estimates how long it takes to charge a VinFast VF8 electric SUV between two states of charge. The VF8 typically uses an 87.7 kWh battery pack (depending on trim and battery option), but you can enter any capacity to match your exact vehicle. Charging speed depends on the charger you use — a home Level 2 wallbox (about 7–11 kW), a workplace charger, or a DC fast charger.
How to use it
Enter your battery capacity in kWh, the power output of your charger in kW, your current and target charge percentages, and a charging efficiency. A realistic efficiency for AC home charging is around 85–90% because some energy is lost as heat. The calculator returns the total charge time in hours and minutes, plus the actual energy added.
The formula explained
First we find the energy needed: battery capacity multiplied by the percentage gain (target minus start, divided by 100). Then we divide that by the effective charging power — the charger power multiplied by efficiency. The result is time in hours. Note this is a simplified linear model; real DC fast charging slows down (tapers) above roughly 80% to protect the battery, so high-percent fast-charge times in practice are longer than a flat estimate.
$$t = \frac{\text{Battery} \times (\text{Target} - \text{Start})/100}{\text{Power} \times (\text{Efficiency}/100)}$$
Worked example
Suppose you charge an 87.7 kWh VF8 from 20% to 80% on an 11 kW home charger at 90% efficiency. Energy needed = \(87.7 \times (80-20)/100 = 52.62\) kWh. Effective power = \(11 \times 0.90 = 9.9\) kW. Time = \(52.62 / 9.9 \approx 5.32\) hours, or about 5 hours 19 minutes.
FAQ
Why does the calculator overestimate fast charging above 80%? DC fast chargers reduce power as the battery fills, so a constant-power estimate is most accurate in the 10–80% range.
What efficiency should I use? Use ~88% for AC/home charging and ~95% for DC fast charging as a rough guide.
Can I use this for other EVs? Yes — just enter that vehicle's battery capacity and charger power.
