DULUTH, MN (KDAL) - With the change back to standard time this weekend, the Duluth Fire Department is reminding residents to change the batteries in smoke and carbon monoxide detectors as you change your clock.  To help accomplish that, they are offering free Energizer batteries to the public, while they last.  There is a limit of two and batteries can be picked up at the City of Duluth Life Safety Office at 615 W. 1st Street starting Thursday.