Makita 18V LXT battery holder wall mount rail
A wall-mounted rail that holds Makita 18V LXT batteries (BL1830, BL1850, BL1860B) by their slide rails, exactly as a tool does, so the pack clicks in and the release button locks it. Each holder is a 78 mm wide dovetail channel 65 mm long with a 12 degree undercut, 0.3 mm clearance on the rail faces and a 3 mm step at the end for the latch to snap behind. The plate is 230 by 90 mm and 5 mm thick for three packs; the rails are printed as one piece with the plate, face down in PETG, and the channel geometry means no supports.
Makita changed the terminal block over the years but not the rails, so this holder spans generations if the clearance is right for your printer. In SpeakCAD you set the pack count, preview the plate in the browser without paying, ask for a 40V XGT variant in the chat, and download the STL.
Design a wall plate 230 mm wide, 90 mm tall and 5 mm thick carrying three dovetail battery channels 78 mm wide and 65 mm long on 76 mm centres with a 12 degree undercut, 0.3 mm rail clearance, a 3 mm latch step at the closed end, and four 4.5 mm countersunk screw holes.