does any one know if there are any rules about not haveing two of the 12 volt batteries on your robot. one that powers the robot and another for weight in the front of the robot.
i will upload a picture later today so that you can see what i am talking about.
Yes, there is a rule that specifically says you can only have one 12v battery on your robot.
“<R45> Items specifically PROHIBITED from use on the ROBOT include:
…
More than one primary battery, or more than one back-up battery”
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If you need ballast, find something else! A battery is a dangerous thing.
thanks for the information.
no its not allowed… just get a ton of steel that you can use as ballast and put it up there (=
In a game of speed, weight is never a good thing.
Is there a way that you wouldn’t have to use ballast, or place the battery up front where the ballast would go.
You don’t want weight on fast robots, (but maybe you do) any hints on what your robot is, or what it looks like.
Ballast is still governed by other rules. Be sure it meets the flowchart for allowables and that it is securely mounted on your robot. Tywraps do not count!
You can buy 5 and 10 lb iron weights at discount department stores, and the have a convenient hole thru the center for mounting.
get some lead i litterly have a ton of it in my back yard it works great as a counter weight.
And Small Parts still sells 27 pound bricks of lead. We have used them in the past as ballast (many, many years ago - ahhhh, for the good old days, when our robots always seemed to come in well under weight instead of well over… 
)
-dave
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Hmmm. Years of handling lead; that might explain some things… 
On a philosophical note, does a battery count as a battery if it’s not part of the electrical system? Yes, yes, I know the rules about one and only one 12v primary battery, but if it’s not plugged into anything is it really a battery? Is it not just a battery shaped weight? Not that I’m advocating for using extra batteries as weights, but still an interesting point of discussion.
Is a battery a battery if it’s not part of an electrical system? If not, then someone needs to go after Duracell and Energizer for false advertising.[/sarcasm]
Seriously, I would argue that a battery is a battery at any time. If it is only a battery when current is flowing, then anytime the main breaker is hit, the battery becomes a battery-shaped weight. If it is only a battery when hooked into the electrical system, then you’re charging a battery-shaped weight. (Don’t get any ideas.)
More importantly, a battery has the potential to suddenly become a spark generator at any time. As soon as it hits metal on both contacts, it becomes a safety hazard, but it may or may not be plugged into an electrical system. Is it not a battery then?
Gentlemen,
Although lead seems to be an ideal ballast material, remember that in some areas lead is considered a hazardous material. It may not be cut or machined at events and should be painted or coated to prevent students (and mentors) from ingesting contaminants while eating with their hands.
Last year we filled two acculator tanks with lead shot worked great because we were not using air and you can fit about 5lbs into one, (i think) and it is sealed with two plugs.
Ahh, so a battery by any other name is still a battery. I think this is the most important argument against using a battery as a weight, especially when there is plenty of other heavy stuff around that can be used. How about a box of old motors? 
…the old motors would have to be currently available COTS 
How about two one-gallon jugs of water?
Good preparation for next year…
Hmmmm…
We need about that exact weight. I wonder …???
lead, steel, water ?
And when is a potato, just a potato?
If the battery is not plugged in, and its protected with AM Plugs, is it not just a 13 lb NFD?
We used a piece of railroad one year. I came back to find that my fellow mentors had lashed said railroad directly above the RC. Incredibly, it did not end horribly.