The 1st Artillery was reassigned to the Southern Department on 17 April 1780. Some units of the regiment fought at the Siege of Charleston in the spring of 1780. When General Johann de Kalb was sent south in 1780, Carrington accompanied his division with three artillery companies. Harrison arrived and assumed command, due to his superior rank. At the Battle of Camden on 16 August 1780, Harrison directed six artillery pieces. Two more guns were loaned to Colonel Thomas Sumter's partisans and 10 were left in the rear for lack of horses to pull them. The regiment was reorganized to consist of 10 companies on 1 January 1781. At the Battle of Hobkirk's Hill on 25 April 1781, Harrison commanded three 6-pound cannons and 40 artillerists. At the Battle of Eutaw Springs on 8 September 1781, the Americans had two 3-pounders under Captain William Gaines and two 6-pounders under Captain William Brown.