Using battery packs as "nonfunctional" decoration

I’m not sure if this has been answered or not.

Are additional 7.2V battery packs allowed to be used as non-functional decorations? And if so, would using them as a counter-weight be considered “non-functional”?

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If you are talking about Cortex, then no, they cannot be used if they are non-functional. We know because we tried years ago (don’t think that has changed).

The key to “non-functional” is that the robot should achieve its function without it on the robot. Meaning, as inspectors/referees, we can ask the non-functional item be removed from the robot.

In the example you give of counter balance, this implies that the robot would not be able to maintain its balance properly and tip. So, the battery pack, aka, counter-weight, would count as functional. Similarly, you can no use an old 7.2V as a counter weight on a V5 system, it is not permitted. You may use it as a counter weight as long as the second 7.2v battery has a power expander. (you need not have them connected to the old cortex).

Similar questions were asked in the Q&A about air reservoir tanks, and if I recall correctly, deemed illegal.

For all matters about legal use of materials that seem unclear, the correct forum is to post the question on the Official Q&A on

Have fun creating new an exciting designs!


I would recommend a stack of 5x25 steel plates, or 1x25 steel bar, for high-density counterweights.


I wouldn’t recommend this anyways, as the densest part in vex that is easily scalable is high strength shafts. Normal shafts work too, but they are slightly less dense when stacked. These two would take up far less room than the equivalent weight in batteries or air reservoir tanks.

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Even better for the combination of density and attachment ease: make a stack of steel plates, place normal shafts through the small square openings, and lots of screws through the larger openings. Use those screws to attach the weight to the robot as required.