I am asking for a revision of Rule 5 in light of he current Global Meltdown.
Several teams from our country hope to be competing in Dallas and we have a problem. We all started with the VEX Robot Battery Pack that takes loose AA batteries. We and the other teams have invested (heaps) in rechargable batteries to run our robots and save the environment. Now we see that we have to go out and waste money buying the 7.2V Robot Battery packs, fast chargers and so on. If we are forced to do this then we will have to tell some of our team that batteries are going instead of them to Dallas.
Please can we change that rule to read "The only allowable source of power for a VEX Robotics Competition Robot is a single (1)
VEX 7.2V Robot Battery Pack or a single (1) official VEX Robot Battery Holder with rechargable batteries, unless the robot is utilizing the VEX Power Expander.
This will help teams during the current economic crisis and not limit the competition to the wealthy.
The reason VEX will not allow this is for safety reasons. By using batteries not made by IFI there is a certain risk to the competitiors. However the good news is you can buy the batteries individually for $20 each: http://www.vexrobotics.com/vex-power-products.shtml#276-2183
Another thing to think about is this: If IFI rules that you can only use the battery packs and not AAs you could ask for teams that are going to be in Dallas to allow you to borrow a battery or two. I’m sure there are enough teams out there who could spare at least one battery that you could be set for the weekend. Then next year you will hopefully have enough in your budget to purchase batteries.
Good idea Corpralchee! I really like this suggestion.
We (Team 42) had to decline our invitation to Dallas, but teams from nearby Gar-Field High School and from Carroll County 4H are going to Dallas - I could have them bring our 6-8 batteries (and our charger) to you if you need to borrow them.
Thanks for the offer of battery loans for New Zealand teams at World Champs. When we find out which teams are going to Dallas we’ll get them to contact you.
It is unlikely that this rule would be amended. Allowing 6 cells individually could allow teams to populate the battery holder with batteries with a higher amp*hour rating and/or a higher nominal voltage. This would invite a “battery war” to get a competitive advantage.
I agree with mike. They won’t do it for the same reason that they make us use vex batteries. It is possible to get more powerful 7.2 batteries and they will only keep getting better. So their batteries are an acceptable standard although from a competitors perspective it would be nice to have more options. I wish we could loan a battery to the cause but we are down to 2 vex batteries for similar reasons.
I understand what you are saying but a higher Amp Hour rating will not make your robot better or faster you will just need to change your batteries less often. We are talking about a game that lasts 2min 20 seconds. A higher voltage could, in theory, make a difference but I am not sure it would be noticable.
I agree with not alowing other types of 7v2 battery pack as there are some monsters out there but AA bateries have a voltage and capacity limited but physics. NiCd and NiMh cannot give you more for their size and volumn than the chemical reaction allows without some major compromises.
I would prefer to see the rule changed until the recession is over. After all a superior robot design, good drivers and solid tactics coupled with a bit of luck will win everytime over a slightly better battery.
Thanks for the very kind offers but I hope they change the rules so we will not have to take you up on them.
How long do the batteries take to charge and how many does each team need?
A transmitter battery will last about 10 matches and takes about 90 minutes to recharge from that point.
A robot battery will last 2-4 matches depending on the number of motors you have. Our 10 motor robot could easily do two matches. About 30-45 minute recharge from that point.
We come to the event with all four fully charged (two of each type). All of our teams have two transmitters.
Each of our teams has 2 robot batteries. They use them for 2 matches then put them in the charger while using the next battery.
Across lunch they will charge one of the transmitter battery for 30 mins, then put the other in until their next match.
We’ve not had a problem with this setup and have gotten through a full day of competition.
So I’d say minimal is two of each and a single charger per team. Best would be four of each and two chargers. Anything over that would be overkill.
We use the same setup as above and we have non vex batteries we use for testing which we found cheaper. So our vex batteries are just for matches. We charge them after every match and deal with the fact that we may shorten their life because we view this as an acceptable risk to take to have fully charged batteries for every round.
I understand why they would want to standardize the 7.2 robot battery. But is there any similar electrical issue concerning the transmitter batteries? If AA batteries could be used in the transmitters, this could help teams on the day of an event, and I can’t see any advantage that AA batteries in the transmitter would have over the 9.6 volt rechargeable. That way, only duplicates of the 7.2 v battery would need to be purchased.
I dont remember any rule on that, and ive never seen a controller opened to see what the battery was. I agree that it makes no difference either way. If there is a rule requiring the use of vex batteries in the transmitter it should be changed in my opinion.
Admittedly, I’ve never seen anyone open a transmitter to check the battery, but technically, you could be disqualified. We decided it wasn’t worth saving $20 to risk being DQ’d (we skimped on the $80 low-cost field and made cardboard models instead).
I agree, they should allow AA transmitter batteries.
That is is certainly posted in the Official Elevation Q&A, but no specific rule is sited in the post. They’ve also posted several times that anything that isn’t specifically prohibited is allowed.
I’ve looked through the official rules, and I haven’t seen any reference to transmitter power at all. The only rule that even mentions the transmitter is <R8>, but that just says that you can only use 1 or 2 per robot, and that they can’t be modified. The inspection guidelines don’t mention the transmitter at all.
It may be worth somebody replying to that thread with a request for clarification.
Our team did have VEX batteries but once they allowed us to buy others they got sent back unfortunately.
we did use 7.2V 2000mah batteries on the robots though. And with the exchange rate as it is its more like $40 a battery for us.
