Back-up Battery question
 

Hello,
I've been told that new yellow back-up battery is all we are allowed to use for the regionals. I want to know if that is true, but I have been searching for a place to buy them and I can't seem to find anyplace. Ifirobotics only has the blue ones, and I am unsure which kind we are allowed to use. I went throught the manuals and didn't see anything. I looked though CD and I didn't find anything either. So I guess my question is are we allowed to use the blue back-up battery? And if not where can I purchase the yellow ones. I'm sorry if this is somewhere obvious, but I just can't seem to find any information.

Thanks
Josh

Re: Back-up Battery question
 

According to rule R73:
So you can use any 7.2V NiCad battery including the blue one available for purchase from IFI.

Re: Back-up Battery question
 

You received a blue backup battery in your KOP. The intended purpose is so that you can use it on your robot.

Also:

Re: Back-up Battery question
 

Some teams (such as mine) received a yellow backup battery in their kits. I believe this is what led to the confusion.

Re: Back-up Battery question
 

But!!!! you must use the supplied charger in the Kit of Parts! None of you guys included that, so I thought I should. And yes, I do recommend getting a larger capacity battery, and using it the whole day, and charging it overnight at competition.

Re: Back-up Battery question
 

Now that I do not believe is true. It is completely true that you must use the supplied charger in the kit of parts for the main 12v battery, but you do not have to use the supplied charger for the backup battery so long as your backup battery charger is still safe. The reason being that the backup battery you might have may not have a compatible adaptor for the [supplied] charger, and it would be extremely silly to require you to create an adaptor to fit just for charging.

-Danny

Re: Back-up Battery question
 

Danny,

Your point is well taken but is not supported by exact interpretation of the rules.

This is one of the FIRST rules which is largely non-enforceable. I also agree that, from an engineering standpoint, there are many better solutions than the provided charger. This is particularly true of "smart" chargers which monitor the state of charge of the battery (they utilize an embedded microcontroller and look for the minus dv/dt "bump") and adjust the charging current accordingly.

As it stands right now, few inspectors will walk the pits looking at your NiCad chargers. However, if pressed, they would have little choice than to quote <R56>.

I invite you to air your concerns on the FIRST Q&A. Only by airing these concerns to FIRST will we get the rules changed.

That's JMHO...

Mike

Re: Back-up Battery question
 

Concern aired. Hopefully I'll get an answer.

-Danny

Re: Back-up Battery question
 

Danny,
Mike gave you the answer, I am afraid. The robot rules are very specific. I prefer to inspect robots in their pit as do many other inspectors. This prevents a pile up at the weighin and size stations and it gives us a chance to make students feel a little more comfortable. I like to check out the pit and see chargers, extra compressors and safety violations that may have been missed by the safety people. It's all part of the full service.

Re: Back-up Battery question
 

Yeah, I understand why the rule is there, but now I have to run out and find one of those funky connectors for the charger so I can charge our COTS NiCad battery as well as the provided NiCad battery. The Q&A gave a definitive answer for me - after reading Mike's response I knew what the answer would be, but I had to ask anyway.

Thanks!
-Danny

Re: Back-up Battery question
 

Not quite, but close. (Emphasis in rule my own.)

Re: Back-up Battery question
 

Just to clarify, not only are you limited to the 2007 charger for this year's back-up battery, you're limited to that charger for ALL your back-up batteries you use this year.

http://forums.usfirst.org/showthread.php?t=4853

Make sure to charge your back-ups to full before the competition!

Re: Back-up Battery question
 

You only need two backup batteries. One in the robot, and one on the charger. If you change the backup battery when you change the main battery, and keep the swapped out backup battery on the charger, you will never fall behind on the charge of the backup battery. Don't leave the backup battery on the supplied KOP charger overnight. It will overheat it.

It is useful to use the 15 amp power pole connector on the backup battery. By using this connector on the battery, the robot, and on the charger, you will avoid problems with intermittent connections.

Eugene

Re: Back-up Battery question
 

QI'yaH!

For those of you who don't speak Klingon, that's an expression of dismay. To put it mildly. The 2007 charger doesn't indicate when the battery is fully charged, nor does it stop charging before the battery is overcharged. That settles it -- we're using the onboard charger. We'll also be pulling the breaker supplying it when the robot is not in use.

Re: Back-up Battery question
 

I asked a question about the backup battery charger on the Q/A a few days ago. I pointed out that an overcharged battery is a safety hazard.