the battery lasts max 10 hours if you only use the radio with 50% or less of the volume you can only get to 20 hours with the headphones off !!! if you want to use all the functions of the headphones with max volume they won't last 6 hours !!! I am disappointed with the advertisement of 20 hours !!! and the radio frequencies below 89 don't work for me (from 88-98 the frequency doesn't pick up anything )... which seems very strange to me because above 89 everything works normally ...