Abstract: A device for powering a number of different electrical loads, especially on bicycles with or without auxiliary motors. The device includes a generator, a drive means for the generator (on a bicycle to cooperate with a wheel of the bicycle), transmission gear means connected in advance of the generator, an accumulator, and switching means for switching between powering of the loads by the generator and accumulator and for constant charging of the accumulator by the generator. The generator, transmission gear means, accumulator and switching means are arranged in a common closed housing. The transmission gear means is connected to the drive means by a flexible shaft. An adaptor is provided by which the rotary motion of a wheel is taken up and transferred by the flexible shaft to the transmission gear means.