Vauxhall would much rather you called the Ampera an extended-range electric vehicle than a hybrid, and for good reason. It is a hybrid, but strictly speaking it is a series hybrid, at least most of the time.
The Ampera’s primary power source is a 148bhp AC synchronous electric friction motor, which draws electricity from a liquid-heated and cooled 16kWh lithium ion battery via a DC to AC current inverter.
The battery takes six hours to charge from a 13A domestic socket and is managed by an electronic power control module that taps into just 65 per cent of its total capacity in order to maximise operational life. However, that 65 per cent capacity is enough to give the Ampera an all-electric range of between 25 and 50 miles depending on temperature and usage, says Vauxhall.
Which, according to GM’s research, could satisfy the daily commuting needs of between 80 and 85 percent of the western motoring population without any consumption of petrol at all.
The Ampera even has an answer should you drain the petrol tank dry. That 22 per ent of remaining battery charge gives three to four miles of emergency electric-only range
There are two other power units under the Ampera’s bonnet besides the main electric motor. One is a 71bhp electric motor/generator, and the other an 85bhp 1.4-litre four-cylinder petrol engine. All three are connected to the Ampera’s front wheels via a planetary gearbox and a system of electronic clutches.
When the Ampera’s battery is depleted to 22 percent charge, the car enters range-extender mode and its 1.4-litre petrol engine starts, usually only to provide electrical power for the main traction motor and to maintain minimum charge in the battery.
In this mode, the Ampera can drive for up to 310 miles, sucking petrol from a 35-litre tank sited behind the battery pack. Range anxiety will be an unknown concept to Ampera owners.
Another advantage of the Voltec powertrain, and what makes it different from conventional range extenders such as the BMW i3 Range Extender, is that when at motorway speeds the planetary gearbox can blend power from both electric motors, allowing the main motor to ‘downspeed’ and increase efficiency.
In certain circumstances, the petrol engine can also connect directly to the wheels via the motor/generator, but only in conditions of high demand and at high speeds – which, in practice, generally means motorway speeds above 65mph. And then it is only to assist the main electric motor.