There seems to be an ever-growing number of electrically-powered devices in cars: digital instruments, heaters, fans, air conditioners, ever more powerful sound systems, built-in TVs, flashing indicators, navigation systems etc, and heaven only knows what is powered through the cigarette lighter. Most of these take only a small amount of electricity, and some are only on for short periods, but cumulatively the power required will be significant. You never get something for nothing, so presumably the bottom line is an increase in fuel consumption - has anybody ever measured it?