An arrangement for measuring the voltage of a battery to determine the state of charge of the battery when used to operate electrical timepieces. A pair of momentary contact switches are actuated by the hours wheel of the clock mechanism on the one hand, and by either the minutes wheel or the seconds wheel of the clock mechanism on the other hand, and when actuated in coincidence complete an electrical circuit which connects the battery with a voltage measuring instrument. An indicating device associated with the instrument indicates the measurement taken and is held in place by a holding device, after the measurement has been completed. The indicating device becomes released and permitted to turn to its initial position prior to the instant when a subsequent measurement is to be taken.