Abstract: The invention relates to a method and device arrangement for feeding power to a wrist device, such as for example a mobile phone, a GPS device, heart rate monitor or the like. With the help of different embodiments of the invention also wrist devices with relatively high power consumption can be implemented, which devices nevertheless have small external dimensions and are light weighted. Method and device according to the invention for connecting the battery cells to each other enable a more flexible and advantageous structure of the wrist band both on the point of view of usability and manufacture. A varying number of battery cells can be connected and they can vary in size according to needs. Small number of conductors enables a moving and reliable contact surface between battery cells. Depending on the application, two or three contacts are needed, depending on whether the charging voltage is lead to the battery cells separately.