Some additional information -
Roberts’ Battery was temporarily assigned to Montgomery’s 14th Georgia Light Artillery Battalion as Company E.
(CSR Unit Information for Montgomery’s Battalion)
A requisition dated 4 October 1862 refers to Roberts’ Battery, Montgomery’s Battalion Georgia Artillery.
(CSR records for Lieut. Callaway of Wiggins’ Battery p.19)
Rice E. Graves, Chief of Artillery of Breckinridge’s Army of Middle Tennessee, reports on 11 November 1862 that Roberts’ Battery (along with Freeman’s Tennessee Battery) had been assigned to Forrest’s Cavalry Brigade. The battery at this time comprised 2 six-pounder guns and 2 12-pounder bronze howitzers. Graves also provides information on the disposition of the batteries that made up Montgomery’s Battalion.
(OR Volume 20, Part 2, p.399)
Forrest mentions Roberts' Battery in his report of the Action at Nashville on 5 November 1862.
(OR Volume 20, Part 1, pp.6-7)
My theory is that Roberts' Battery was transferred from Liddell's Brigade to the reserve artillery of the army at the reorganisation at Chattanooga prior to the invasion of Kentucky although I can find no definite order to that effect. Swett's Mississippi Battery was assigned to Liddell instead. The battery then became part of The Army of Middle Tennessee when that unit was organised in October 1862. It was then transferred to cavalry service with Forrest, probably in late October. Sometime prior to The Battle of Stones River the battery was transferred from Forrest to Wheeler.