A PHEV LIKE NO OTHER
The Prius Prime delivers the best of both worlds, writes David Thomson.
THE Toyota Prius hybrid was once the poster child for the electriccar revolution. Now allelectric cars are the big thing, with the Nissan Leaf being topofmind for everyday green drivers along with Tesla as the banner bearer for ecoconscious motorists with more to spend.
In comparison to these allelectric machines, the Prius hybrid may seem old hat, but what of its lesserknown close cousin, the Prius Prime?
In electric motoring nomenclature, the Prius Prime is a PHEV, or plugin hybrid electric vehicle. As such, it combines a conventional engine with a batterypowered electric motor that can be recharged by plugging into the mains.
Available here in only one variant, the Prius Prime is priced at $48,490 — $2000 more than the topspec version of the regular Prius hybrid, on which it is based.
As a PHEV, the Prius Prime is designed to deliver the best of two worlds: allelectric zerocarbon motoring for shorter trips with the flexibility of backup petrol power to free the driver from the range restriction issues that are partandparcel of pureelectric vehicles.
Purists may turn up their noses at the PHEV approach because a petrolelectric hybrid delivers lowcarbon rather than zerocarbon motoring. But, as Drivesouth’s spell with the latest Prius Prime showed, the extent of that carbon reduction can be significant.
The secondgeneration Prius Prime, as tested, is derived from the fourth generation of the Prius. It deploys a far more powerful 8.8 kWh lithiumion battery, and a new 68kW dual electric motor system, operated in conjunction with a 1.8 litre Atkinson cycle petrol engine.
Designed for sustained driving on battery power alone, the Prius Prime requires a more powerful, highercapacity battery than the Prius. To accommodate that larger battery, the car’s length has been extended, boot space sacrificed (360 litres) and the spare wheel abandoned (there is an emergency reinflation kit instead).
The larger battery and plugin ancillary also add weight, with the Prime being around 130kg heavier than a Prius. This weight gain, incurred despite offsetting features such as an ultralight carbon fibre reinforced plastic rear hatchback, has forced Toyota to reconfigure the rear of the cabin for two occupants (with a fixed centre armrest) rather than three.
Along with the usual choice of Eco, Normal and Power drive modes, the Prime has several driverselectable electric/hybrid modes: in EV mode, the car runs on electric power alone for as long as possible; in Hybrid mode, it combines electric and petrol power to what it calculates is the best economy effect; in Charge mode, the petrol engine recharges the battery as well as propelling the car; lastly, there’s EV City mode, which is basically a lowpower allelectric mode that maximises batteryonly range.
Toyota has sharpened the handling of the regular Prius over the years to the extent that the latest version is fun to drive. However, with its extra weight, located mostly at the rear, the Prius
Prime’s dynamics are not of the same standard. The steering, while precise, provides little in the way of feel and hard cornering provokes a fair amount of body roll. The rear suspension is also easily unsettled by surface imperfections, though overall ride quality is good.
On a more positive note, the
Prius Prime will accelerate steadily to the legal speed limit and cruise there on battery power alone. Noise levels are low, especially when humming along in a fullyelectric mode.
Just how long the Prime will run before the petrol engine comes into play is dependent on several factors, including terrain, speed and traffic volumes.
In driving the test car to and from work during the week, charging it at nights, and taking a relatively short outoftown trip at the weekend, it was possible to cover 40km45km before the petrol engine or a recharge was required. With a round trip from home to work of roughly 15km, that was ample for allelectric commuting and some errandrunning, without the fuss of recharging during the day.
The recharge time for the test car was impressive, too; even when fully drained, the battery returned to full charge in 45 hours hooked up to the regular 240volt home supply.
Allup, I covered just over 160km in the Prime, generally running it in pure electric mode around town, but allowing the car to optimise efficiency by using hybrid mode on the open road.
The petrol gauge barely budged from full, with the total amount of petrol used on test a miserly two litres. That equates to an impressive economy return of 1.25l/100km for a week’s driving and a petrol bill of under five dollars. At a rough estimate, electricity recharging costs were about the same again.
On this basis, the Prius Prime PHEV makes a decent case for itself as an environmentally credible alternative to a conventional or nonplug in hybrid car for those engaged in mainly urban driving. The comparison
with allelectric alternatives is not as straightforward but if — as is often the case — you’re an electric car driver who retains a conventionallypowered vehicle for longer trips, then you might consider whether having a PHEV such as the Prius Prime means you could own one car rather than two.