I have modified the lid of EmanuelB's battery box to add a text label, the remainder of the lid is the same as the original. This lid fits on the battery box by EmanuelB so you'll need to get the base box there. This lid should be printable without supports as long as your printer can handle 45º overhang. The text should be facing the build plate when slicing.

Note: The print in my photographs is an earlier version of the design, the version attached here has thicker letters and more closely resembles the original font. Also the printer that I have to use is a bit sloppy for the first few layers so the front edges of the letters are not as well defined as they should be.