Rechargeable batteries for the RCX

[Evenstar_342]

Mr. Skierkiewicz,

My team found your post very informative. Even though we've moved to the NXT, some of my fellow mentors investigated the battery terminals and found them to be just fine. Our rationale for replacing the batteries was the desire to keep as much constant as possible. Not being master programmers or electrical engineers, our students always had problems with friction and alignment especially. Probably some of the time that the robot was off was due to those issues instead of battery life. However, we felt that by having a decent idea of the freshness of the batteries would eliminate one variable, so we could continue problem solving more effectively. We were consistently underwhelmed with Robolab's meter, your explanation could account for several instances of robots dying at summer camps when the meter read almost full (I almost slept through that semester of physics though, so I could be totally wrong ). We're not complaining, a top two finish four out of five years is pretty good and, most importantly, we've inspired legions of students to discover science and technology.

[Al Skierkiewicz]

Even,
That is always good news. Our team does not have the resources for NXT yet but they look very impressive. Time will tell on battery issues with these platforms, since I have no available data on battery use yet. I think that FLL will have to migrate to a larger playing surface in the future for the NXT since the robots I saw were so much larger.
I am glad your team found the post informative. Let me know if I can help in the future.

[Danny Diaz]

Originally Posted by Al Skierkiewicz

I think that FLL will have to migrate to a larger playing surface in the future for the NXT since the robots I saw were so much larger.

I hope not. The table surface is already very large - it's wide enough that I have difficulty resetting the center "shared" mission, and it's long enough that I have a difficult time running up and down the table to help out kids playing on the game board because *they* can't reach their robots either. I would hope that FLL will not grow the game board size at all, and make the teams just design smarter. Already the "base" areas are huge - compared to previous years where RCX-only robots were competing - and the referees give tons of flexibility on that rule as it is. I'd like to see less delicate mission models and slightly more complex activities for robots to solve/complete - I loved the "Smart Medicine" mission with the Buckeyball from this past year, the "Protect the Pumping Station" from the mission in Ocean Odyssey, and the "Climb the Stairs" mission from No Limits - those were all simple in concept, but could be done in multiple ways and were as simple or complicated as teams wanted to be. The models were fairly easy to build (the stairs maybe were a pain), they were definitely solid, and they were fun to complete.

That's just my $0.02 as a head referee...

-Danny

[Andrew Schuetze]

Okay, so I just ran my first two summer camps with the Lego NXT and the Lego supplied rechargable battery pack and DC power supply. In the first camp which was a half-day version for six weeks. The teams only had to recharge the battery pack every couple of days as they only were in robotics for 1 to 2 hours a day. I don't have any good data for the full-day , two-week camp as I only taught the morning and witnessed the teams recharging over-night for good measure. Lego must have designed the NXT to operate on the voltage coming from these packs and I haven't a clue as to what type of system they are using, NiCad, LMH, Alkaline ,,,

[Al Skierkiewicz]

According to Lego this NXT only pack is rechargeable Lithium.