You may be having trouble because Robertson's-Dent's Battery was a Florida unit. It came by the name of Dent's Alabama Battery prior to the Chattanooga Campaign.

..."Robertson’s Florida Battery was organized in Pensacola, Florida in late 1861 and was known, as was the custom, by the name of its commanding officer, Captain Felix H. Robertson. Robertson was a Texan who resigned from West Point just prior to graduation and offered his services to the Confederacy. He was commissioned a Second Lieutenant of artillery and was present at the bombardment of Fort Sumter before being sent to Pensacola. In January of 1862 at the age of twenty-two, he was given command of the newly formed battery.

By March of 1862 the battery was in Corinth, Mississippi as part of Gen. Braxton Bragg’s Corps of 10,000 men. It left Pensacola with one caisson, 231 rounds of ammunition and four 12-pounder Napoleon guns supplied by Leeds & Company of New Orleans. The battery was issued a battery wagon and traveling forge in Montgomery but arrived at Corinth in need of additional equipment. Robertson and his men first saw action on April 6, 1862 at the battle of Shiloh. By Murfreesboro, the battery had added two more Napoleons for a total of six guns. At Chickamauga, Major Robertson was in command of a battalion of reserve artillery and Captain S. H. Dent assumed command of the battery. Dent, a Maryland native, practiced law in Eufaula, Alabama from 1856-1861. He enlisted in the Eufaula Rifles and became adjutant of the 1st Alabama Infantry in 1861. In April 1862, he joined the newly-formed Robertson's Battery, later called Dent's Battery when he became its captain in 1863. After the war, he returned to Eufaula, where he entered business and practiced law. By the time the Battery reached Chattanooga in December of 1863, it was known as Dent’s Alabama Battery. After participating in the Atlanta Campaign and the Battles of Franklin and Nashville, the remaining troops were sent to man the coastal defenses of Mobile. Those not captured at Spanish Fort and Blakeley were surrendered at Citronelle, Alabama on May 4, 1865".....