There is a specific thing to use as a weight to avoid this question Look on bricklink for 73090A or 73090B It looks like the 73090B is cheaper. Tell your team good job on innovation. On 2013-10-28 12:11, Scott Rakestraw wrote: > My Code Crackers teams wants to add counter weight to the back of their robot to keep it from tipping due to a front heavy attachment. They asked if they could use a spare NXT battery since it is manufactured by Lego. In looking at rule 4 - Equipment, it depends on how batteries are classified. To clarify if this is within the rules, are Lego batteries considered electric or non-electric? > > "REGULAR ELEMENTS - You may use as many non-electric LEGO elements as you like, including pneumatics, rubber bands, > > and string, and they may be from any source or set (MINDSTORMS(R)/TECHNIC/DUPLO(R)/BIONICLE(tm)/STAR WARS(tm)/ > > HARRY POTTER(tm)/etc.). Exception: Factory-made wind-up/pull-back "motors" are not allowed. > > Scott Rakestraw > > www.fllstartingpoint.com > > ------------------------- > > To UNSUBSCRIBE or CHANGE your settings, please visit https://listserv.jmu.edu/archives/vadcfll-l.html [1] and select "Join or leave the list". > VADCFLL administrative announcements are sent via VADCFLL-ANNOUNCEMENTS-L. Visit https://listserv.jmu.edu/archives/vadcfll-announcements-l.html [2] to subscribe. Links: ------ [1] https://listserv.jmu.edu/archives/vadcfll-l.html [2] https://listserv.jmu.edu/archives/vadcfll-announcements-l.html -- To UNSUBSCRIBE or CHANGE your settings, please visit https://listserv.jmu.edu/archives/vadcfll-l.html and select "Join or leave the list". -- VADCFLL administrative announcements are sent via VADCFLL-ANNOUNCEMENTS-L. Visit https://listserv.jmu.edu/archives/vadcfll-ANNOUNCEMENTS-l.html to subscribe.