Organized in September 1861, Welfley's Independent Battery fought at Pea Ridge and in the White River campaign.

After its name changed to Battery B, 1st Missouri in December 1862, it fought at Cape Girardeau, Chalk Bluff, Vicksburg, Sterling's Plantation, and Brownsville.

It joined Samuel Ryan Curtis's campaign against Sterling Price in Missouri and Arkansas from January to March 1862.

The three artillery pieces were ordered to support Cyrus Bussey's cavalry, but the Union horsemen were routed and stampeded through the battery as it moved forward.

Osterhaus sent the artillerists to retrieve the howitzer, covered by two companies of the 12th Missouri Volunteer Infantry, and the lost gun was recovered.

[3] Colonel Nicholas Greusel deployed his brigade along the southern edge of a cleared field with the 36th Illinois Infantry Regiment on the left, then in order, the 4th Ohio Battery, the 12th Missouri, Welfley's howitzers, and the 22nd Indiana Infantry Regiment on the right.

With Osterhaus's approval, Welfley and the other battery commander began firing howitzer shells over the strip of woods in their front.

[3] Later, Welfley's three howitzers began shelling the woods to the east, where a Confederate brigade was battling Colonel Jefferson C. Davis's Union 3rd Division.

When Osterhaus reported finding an excellent artillery position, Sigel ordered him to move forward with the 44th Illinois Infantry Regiment and that the rest of his units would follow.

From 25 May to 14 July, the battery served in the White River campaign, ending in the capture of Helena, Arkansas.

[1] The original Battery B, 1st Missouri Light Artillery Regiment was authorized at St. Louis on 1 September 1861.

The original Battery B was briefly assigned to the 2nd Brigade, Army Southwest Missouri but disbanded in January 1862.

The unit was reassigned to Artillery, 2nd Brigade, Francis J. Herron's Division, XIII Corps, Army of the Tennessee in June–July 1863.

[7] The 2nd Brigade of Herron's Division was led by William W. Orme and included Battery B as well as the 19th Iowa, 20th Wisconsin, and 94th Illinois Infantry Regiments.

[7] The unit moved to Port Hudson, Louisiana on 23 July and from there to Carrollton on 12–13 August where it was on duty until 5 September.