So,
You have just set off driving at night in your expensive shiny new electric car, it,s dark, headlights on, it,s raining, wipers on, heated rear screen on to keep it clear, you have to use A/C to keep the condensation off the windscreen but at the same time turn on the heater to keep warm, sat nav connected,
kids in the back watching their dvd players connected up.
You reach the first junction where you have to brake, your brake lights bulbs light up and your battery goes dead !