BYD Seal U DM-i vs Hyundai Tucson PHEV: Running Costs, Price and Electric Range

On the BYD side, insurance groups are 32 for the Boost and Comfort trims and 40 for the all-wheel-drive Design, and company car tax on the 2026 to 2027 Benefit in Kind schedule works out at roughly £43 a month for a 20% taxpayer in the Comfort, rising to about £58 for the Boost and £66 for the Design. Carwow's long-term test of the Seal U DM-i averaged around 40 miles per gallon when charged regularly. An insurance group and a CO2 figure for the Tucson PHEV are not established from the sources this comparison uses, so no company car tax or insurance figure is given for it here; a buyer weighing the two on running costs should get both direct from a dealer or an insurer before ordering.

All figures here are the electric-only WLTP range, not a weighted combined mpg figure, and the two cars should never be read against each other on any other basis. The Seal U DM-i's Boost and Design trims cover 50 and 43 miles respectively on a smaller 18.3kWh battery, while the Comfort's larger 26.6kWh pack stretches that to 78 miles, among the longest electric-only ranges of any plug-in hybrid on sale in Britain. The Hyundai Tucson Plug-in Hybrid, on its own 13.8kWh pack, covers up to 43 miles electric-only WLTP on its entry two-wheel-drive Element trim, identical to the Seal U's Design trim and a little behind the Boost and well behind the Comfort. DC rapid charging tells a different story on the BYD side: 18kW maximum means a 30 to 80% top-up takes 35 to 55 minutes depending on battery size, offering little advantage over a 7kW home charger at a motorway services. Hyundai does not publish a DC charging figure for the Tucson PHEV at all; its own performance page describes only AC home and public charging for this model.

Warranty is where the asymmetry between these two is real and should not be flattened into one number. The Seal U DM-i carries a 6-year or 93,750-mile vehicle warranty and an 8-year or 155,350-mile battery warranty with a 70% capacity floor, plus 12 years of bodywork cover. The Tucson PHEV carries Hyundai's standard 5-year warranty with no mileage limit at all, plus a separate 8-year or 100,000-mile high-voltage battery warranty. So BYD's vehicle cover runs a year longer but stops at 93,750 miles, while Hyundai's runs a year less but never stops on mileage; which suits a buyer better depends entirely on how many miles a year they expect to cover. On the battery specifically, BYD's 155,350-mile allowance is 25,000 miles more generous than Hyundai's 100,000 over the same 8 years. Both earn 5-star Euro NCAP ratings. Euro NCAP scored the Seal U DM-i at 90% for adult occupant protection, 86% child occupant, 83% vulnerable road users and 77% safety assist. The Tucson's own 5-star result dates to 2021, on the same generation that remains on sale today including the plug-in hybrid line; Euro NCAP has not published a category breakdown for that test, so this comparison states its star rating only rather than estimating one.

BYD announced on 15 January 2026 an 8-year / 250,000 km (about 155,350-mile) Blade Battery warranty for BEVs and Super Hybrids in Europe, including existing UK cars; ETP3 and some special fleet agreements are excluded. BYD's general UK policy page still lists 125,000 miles, so buyers should verify the VIN-specific warranty booklet or written dealer terms.