This enlarged electric system, which can be charged from a 16-amp driveway wallbox in just two hours and 15mins, can inject torque to the driveline for longer periods. So, despite having identical peak outputs of 139bhp and 195lb ft to the hybrid, and weighing an additional 125kg, the plug-in’s quoted 0-62mph time is actually 0.2sec quicker at 10.6sec.
Those who dislike the revvy nature of a CVT gearbox, as used by the Prius Plug-in, will be happy to hear the Ioniq drives its front wheels via a six-speed dual-clutch automatic. There are also paddles shifters behind the steering wheel.
Our test car was the top-spec Premium SE, which comes with leather seats, steering wheel and a gearlever, and has soft-touch plastics on the top of the dashboard. There’s also a 7.0in touchscreen infotainment system with HD graphics as standard on all plug-in models. This features Apple CarPlay and Android Auto smartphone compatibility.
What's it like?
As you would expect from a plug-in hybrid, this is not a car to be hustled. From the very first mile, the plug-in exhibits the same characteristics as its Ioniq siblings: it's laid-back and hushed, and it always seems to be caught by surprise when asked for maximum acceleration. But this relaxed demeanour won’t have come by accident, given that many buyers in this segment opt for electrified models for that very reason.
When fully charged, the car defaults to EV mode, where the motor does all of the work and the petrol engine only comes into life under heavy acceleration. It’s a shame that you can’t opt to stick with electric power for longer, because the engine kicks in earlier than seems necessary. But even with its occasional intervention, it's still easy to achieve an average miles per gallon that far exceed the trip computer’s 99.9mpg maximum readout. Hyundai claims that the batteries can offer 39 miles of range in this mode, although our urban test brought that figure closer to 30.
When left to make its own decisions in HEV mode, the electric motor does all the work when pulling away, before the petrol engine gently contributes as the speedo rolls into double digits. With gentle throttle applications it’s a seamless process, but ask for more power and the engine’s contribution can suddenly jolt acceleration with a gruff note to match. Keep the throttle pressed and the dual-clutch gearbox, despite being quick-shifting, does noticeably break apart acceleration, making the Ioniq Plug-in feel more conventional than the uninterrupted progress of the similar Prius. Drive with the flow of traffic and you’ll be rewarded with urban economy of around 55mpg.