added battery cover in build123d

Took a look and here is my version with a few suggestions, feel free to use any part or all parts as you see fit:

from build123d import (
    BuildPart,
    BuildSketch,
    BuildLine,
    Box,
    Plane,
    Polyline,
    Location,
    Locations,
    Axis,
    Rot,
    mirror,
    make_face,
    extrude,
    fillet,
    chamfer,
)

COVER_WIDTH = 62
COVER_DEPTH = 37
COVER_HEIGHT = 2

POLY_WIDTH = 25
FILLET_SIZE = 2

BOX_WIDTH = 6

USE_TABS = True  ## False

with BuildPart() as cover:
    with BuildSketch() as s:
        Rectangle(COVER_WIDTH, COVER_DEPTH)
    extrude(amount=COVER_HEIGHT)  # position control, box is now NOT half below XY
    split(bisect_by=Plane.YZ)  # keep only half

    with BuildPart(mode=Mode.PRIVATE) as box_p: # construct private box on the origin and transform later
        with BuildSketch() as s:
            Rectangle(BOX_WIDTH, 6)
        extrude(amount=8)

        if USE_TABS: #placing tabs is easier because the selector is simpler and more robust
            fc2 = faces().filter_by(Axis.X)[-1] #get face center of small edge box
            plane = Plane(fc2).rotated((0, -5, 0)) #rotate -5 degrees about local y-axis
            with BuildSketch(plane) as tab_sk2:
                Rectangle(4, 2, align=(Align.CENTER, Align.MAX)) #align top edge to y-axis
            extrude(until=Until.PREVIOUS) # used extrude-until so that dimensions are not needed
        mirror(about=Plane.YZ) #leverage local centerline symmetry to mirror the tab

    loc = Location(
        (COVER_WIDTH / 2 - 8 - BOX_WIDTH / 2, -COVER_DEPTH / 2 - BOX_WIDTH / 2, 0)
    )
    with Locations(loc):
        add(box_p.part) #move the box into position

    plane = Plane.XZ.offset(-COVER_DEPTH / 2)
    with BuildSketch(plane) as poly_sk:
        with BuildLine(Location((COVER_WIDTH / 2 - POLY_WIDTH, COVER_HEIGHT))) as line:
            Polyline((0, 0), (POLY_WIDTH, 0), (20, 5), (5, 5), (0, 0))
        make_face()
    extrude(amount=COVER_HEIGHT)

    edgs = cover.part.edges().filter_by(Axis.X).group_by(Axis.Y)[2][0]
    fillet(edgs, FILLET_SIZE)
    edgs = cover.part.edges().filter_by(Axis.X).group_by(Axis.Y)[1][1]
    fillet(edgs, FILLET_SIZE)
    #eliminated one fillet with later mirror operation

    if USE_TABS:
        fc = poly_sk.sketch.face().center() # get trapezoid face center
        plane = Plane(
            origin=(fc.X, fc.Y, COVER_HEIGHT + 2), x_dir=(-1, 0, 0), z_dir=(0, 1, 0)
        ) # manually construct a plane with some of the face center coordinates
        with BuildSketch(plane.rotated((5, 0, 0))) as tab_sk: # create sketch on plane rotated about local y-axis
            Rectangle(4, 2, align=(Align.CENTER, Align.MAX))
        extrude(until=Until.PREVIOUS)

    mirror(about=Plane.YZ) #leverage CL symmetry to reduce code-duplication

if __name__ in ['__main__', 'temp']:
    show_object(cover)

The only caveat here is that extrude-until can be sometimes a little less stable than providing a dimension manually. In this case it seems to work very well, but just be advised. One could easily substitute a dimension manually in this case too.

inputlabs / alpakka_case

added battery cover in build123d #23