Power to the people

Electricity is in the air. No, I'm not talking of the highveld thunderstorms which should arrive shortly. I'm talking of electrically driven cars. Painful as the idea may be to us petrolheads, the relentless upward spiral of the fuel price forces us to start thinking about these vehicles. Manufacturers have long ago seen the writing on the wall and all the leading carmakers have invested heavily in the development of cars with electric motors. Their efforts have focused on two concepts. The first is the so-called plug-in electric cars. These rely solely on an electric motor, fed by a storage battery. When the battery is depleted, it has to be recharged from a mains outlet. The second concept is the hybrid electric car — hybrid because it still has an internal combustion engine, but it also has an electric motor driven off a high-voltage storage battery. The internal combustion engine and the electric motor operate in conjunction under the command of a sophisticated powertrain management system. On some hybrids the storage battery is kept at the required state of charge by a generator driven by the petrol engine, supplemented by regenerative braking. On other hybrids (referred to as plug-in hybrids) the onboard charging system can be augmented by charging from mains power at home. A scan of the list of cars on sale in SA revealed a surprising number of electrically assisted vehicles — 38 models in total. Unfortunately 23 of them are priced in excess of a million rand. The most expensive is the Range Rover L SV Autobiography P400e, priced at R3,978,700. There’s an absurdity in these prices: surely if you can fork out over a million rand for a car, the fuel price shouldn't worry you too much. With this in mind I have selected some models selling at under R600,000. They are the ones of which a salaried motorist, driven to the wall by the fuel price, might at least dream. Here are six of them: On the used market the Toyota Yaris Hybrid HSD XS (discontinued), Toyota Auris Hybrid XR (R427,700), Toyota Prius Hybrid (R471,800), Nissan Leaf (R504,975) and Lexus CT 200h S (R533,900). Of these six the Prius is the best known in our country. The version brought into SA is a nonplug-in hybrid. It dates back to 1997 in Japan and 2005 in SA. The current generation is a comfortable family sedan equipped with a 1,8 litre, 71 kW petrol engine, working in parallel with two electric units, a generator and a motor of 53kW, powered by a NiMH battery pack of 202 volts. The battery pack, housed under the back seat, is covered by an eight-year warranty, and reports indicate its service life is usually much longer. The car is front-wheel driven via CVT. The speciallydesigned petrol engine, which plays an important role in the Prius package, employs a version of the Atkinson cycle achieved by variable valve timing. Fuel economy of 27km/litre is claimed. The Auris and Lexus use essentially the same system. The Yaris Hybrid brought a substantially re-engineered powertrain with it. Fuel economy was further improved and the top speed was down to 165km/h. The Nissan Leaf is the only purely electric vehicle in the semi-affordable line-up. Its electric motor, with power output of 80 kW, draws its current from a 360 V lithium-ion battery pack of 24kWh capacity. It has a range of roughly 200km, depending on a variety of factors. Recharging takes about eight hours if done at the normal rate at a home charging dock, 30 minutes if done at a quick-charge port available at dealers. Battery degradation, an inevitable process, is always a concern because it militates against the fuss-free, low-maintenance nature of the electric motor. Nissan guarantees that capacity will remain above 75% of new battery capacity over 160,000km/eight years. In the final analysis the fundamental problem of electric vehicles is that they are too expensive. Put a really affordable one on the market, and even I might decide to trade the sweet song of a happy petrol engine for the sepulchral silence of fluctuating electromagnetic fields. Until that time, a motorbike looks like a far better idea.