BYD Dolphin Surf Boost range under different conditions and battery health levels.
Why real range is below the official figure
WLTP tests run in mild lab conditions at gentle speeds, so nearly every EV undershoots the sticker in real driving. For the BYD Dolphin Surf Boost, a fair planning figure is about 170 miles, roughly 85% of the official 200. That works out at about 3.9 miles per kWh from the 43.2kWh usable battery.
- Motorway runs at 70mph cost the most: air resistance rises sharply with speed
- Winter takes 20 to 25% off: expect around 135 miles on a cold day with the heating on
- Gentle town driving can beat the realistic figure, sometimes even the WLTP one
How battery health changes the picture
Range fades slowly as the battery ages. At 90% battery health the realistic range drops to about 155 miles, which most owners barely notice day to day. At 70% health, the typical warranty threshold, it falls to about 120 miles.
If you are buying a used BYD Dolphin Surf Boost, that spread is the reason to get the battery's actual state of health measured rather than guessing from the odometer. A specialist reads it directly from the car in under an hour.
Related on The EV Pros
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