12V battery failures in hybrids and EVs
This is a huge modern headache because people expect battery trouble on old cars, not nearly-new ones. Which? says owners of full hybrids are 4x more likely than petrol owners to be left with a flat 12V battery. For cars under four years old, the failure rates it found were: 5.6% full hybrids, 3.8% EVs, 3.5% PHEVs, versus 1.4% petrol and 1.8% diesel. Particularly bad examples called out by Which? were the Lexus LBX (29.2%), Hyundai Ioniq 5 (27.3%), Kia EV6 (18.8%) and Kia Soul EV (18.8%). What Car? also shows repeated 12V trouble on Toyota Yaris Cross (23%), Toyota Yaris (22%), Toyota C-HR hybrid (16%), Ford Kuga hybrid/PHEV (14%), MG ZS Electric (10%), and Hyundai Ioniq 5 (20%). Source Source Source Source Source
EV battery-pack / charging / motor faults
These are not always the most frequent faults, but they are among the most worrying. What Car? lists these poor performers: Hyundai Ioniq 5 (80.7% reliability) with faults including 12V battery 20%, EV battery pack 5%; Porsche Taycan (81.2%) with air-con 22%, EV battery pack 13%, 12V battery 7%, charging system 4%; VW ID.4 (79.6%) with electric motor 18%, EV battery pack 11%; Audi Q4 e-tron with EV battery pack 6%, charging system 4%; Genesis GV60 with infotainment 11%, 12V battery 6%, EV battery pack 6%, charging 6%. Source Source Source