The invention relates to a method of monitoring battery characteristics in a radio terminal equipment arrangement. The method comprises measuring battery characteristics of a battery of one or more secondary units communicating with radio terminal equipment; establishing a low-power radio frequency (LPRF) connection between radio terminal equipment and a secondary unit of the radio terminal equipment arrangement. The method also comprises receiving, in the radio terminal equipment, the measured battery characteristics of the one or more secondary units via the established LPRF connection; and giving an indication, by the radio terminal equipment, relating to the battery characteristics of the one or more secondary units.