You can get BAT ERR if the batteries are fully charged, overly discharged, have one or more bad cells, or the charge voltage is too low <13.8V -- View this message in context: http://elecraft.365791.n2.nabble.com/KX3-internal-battery-problem-tp7626247p7626268.html Sent from the Elecraft mailing list archive at Nabble.com.