At the time of the Battle of Chickamauga, Capt Coleman B Ferrell's Battery was serving with General Roddey's Cavalry in the Tennessee Valley. The records show that part (1 officer and 26 enlisted men) of Ferrell's Battery remained in Georgia after Apr 20, 1864. During the absence of Wheeler's Cavalry in East Tennessee, Roddey's command had been assigned to the Army of Tennessee from late February 1864. After Apr 20, 1864, Hannon's Cavalry Brigade and the men from Ferrell's Battery remained with the Army of Tennessee near Dalton GA. If Ferrell's Battery had been serving with Wheeler's Cavalry, it would have been in East Tennessee as well.

Here is a previous post in which assignments and orders from the early 1864 period are noted --
http://history-sites.com/cgi-bin/bbs53x/gacwmb/webbbs_config.pl?read=11628

The 14th Georgia Artillery Battalion was disbanded in late 1862 or early 1863, batteries assigned to different commands. With the exception noted, Ferrell's Battery served under General Roddey's command from the time his regiment organized in the fall of 1862 until the capture of Columbus GA, Apr 16, 1865.

For what its worth, my ancestors lived in Troup County GA during the war, several moving a short distance to Randolph County AL after the war.