Powell was wounded on 2nd July 1863 at the battle of Gettysburg.  He was part of Perry's brigade, the 2nd Florida, and most likely sustained his injury later on in the day, around or after 6pm when he was involved in some of the worst fighting of the battle.     Below is a statement by Lang, who led Perry's Brigade into battle.

Next on Wilcox's left was our lone Fla. brigade, Perry's, now under Lang. It had but three small regiments, and mustered about 700 bayonets. Lang reports as follows :

"At 6 P.m., Wilcox having begun to advance I moved forward, being met at the crest of the first hill with a murderous fire of grape, canister, and musketry. Moving forward at the double quick, the enemy fell back beyond their artillery, where they were attempting to rally, when we reached the crest of the second hill. Seeing this the men opened a galling fire upon them, thickly strewing the ground with their killed and wounded. This threw them into confusion when we charged them with a yell, and they broke and fled into the woods and breastworks beyond, leaving four or five pieces of cannon in my front, carrying off, however, most of the horses and limbers.

"Following them rapidly I arrived behind a small eminence at the foot of the heights, where, the brigade having become much scattered, I halted for the purpose of re-forming, and allowing the men to catch their breath before the final assault upon the heights.

"While reforming,an aid from the right informed me that a heavy force had advanced upon Wilcox's brigade and was forcing it back. At the same time a heavy fire of musketry was poured upon my brigade from the Woods 50 yards in front, which was gallantly met and handsomely replied to by my men. A few moments later another messenger from the right informed me that Wilcox had fallen back and the enemy was then some distance in rear of my right flank. Going to the right I discovered that the enemy had passed me more than 100 yards and were attempting to surround me. I immediately ordered my men back to the road some 300 yards to the rear. Arriving there I found there was no cover under which to rally and continued to fall back, rallying and re-forming upon the line from which we started. In this charge the brigade lost about 300 killed, wounded, and missing."