Bryce, some info for you...

The battalion was constituted in April 1863 (OR Vol.25, Part 2, p.729) with the following batteries -

Letcher Virginia Artillery (Capts. Davidson, Brander)
Crenshaw Virginia Artillery (Capts. Crenshaw, Ellett)
Purcell Virginia Artillery (Capts. Walker, Pegram, McGraw, Fitzhugh, Cayce)
Fredericksburg Virginia Artillery (Capts. Curtis, Braxton, Marye, Pollock)
Pee Dee South Carolina Artillery (Capts. McIntosh, Brunson, Zimmermann)

In May 1864 the McQueen South Carolina Artillery (Capts. Stanley, Gregg) replaced the Pee Dee Artillery.

The battalion, serving in the 3rd Corps, retained this make up through 31 October 1864 where the Fredericksburg Artillery is shown as detached to the 1st Corps (OR Vol.42, Part 3, pp.1193, 1341. The remaining four batteries made up the battalion in January 1865 (OR Vol.46, Part 2, p.1177) and through the Appomattox Campaign (OR Vol.46, Part 1, p.1274).

Greene, Final Battles of the Petersburg Campaign, p.215 states that on 29 March 1865 Gen. Lee directed Pegram’s battalion of 20 guns to report to the far right. Later the same source refers to Pegram’s 6 guns at Five Forks (p.237). An article in the Southern Historical Society Papers, Vol. 14, (Annual Reunion of Pegram’s Battalion) identifies the six guns as ”one gun from his own Battalion, commanded by Lieutenant Hollis of the Crenshaw Battery, and a section from Braxton's Battalion, commanded by Lieutenant Early. Further to the right, sweeping the Gilliam field, were the remaining three guns of "the Crenshaw," commanded by one of the best officers in the Battalion, Captain Tom Ellett.” SHSP Vol. 28 (The Crenshaw Battery) states that the gun under Hollis was captured, the other three guns of the battery escaping.