Jerry brought up a good point.  The following were posted last year, and I’m posting it here again for our new coaches.

 

1) The robot motors run differently with a fully charged battery versus a low battery.  You can see it clearly if you’ve ever used power hand tools.  That battery power drill or screwdriver did not work very well when the battery was low on charge.  So the same program on the robot might not execute the same at the beginning of the day versus at the end of the day when the battery is running low!

2) There is a weight different between the rechargeable battery and the AA.  This might just be enough to throw off a turn or two of the robot and ruin a mission during the tournament.  The center of gravity of the robot also changes as the kids remove or add attachments, and this can affect the robot behavior in the mission as well. 

 

These are some of the small engineering aspects that we hope the kids will pick up during their first FLL season.

 

Cheers,

Curt

 

 

 

From: First Lego League in Virginia and DC [mailto:[log in to unmask]] On Behalf Of Jerry Lorengo
Sent: Friday, October 08, 2010 3:29 PM
To: [log in to unmask]
Subject: Re: [VADCFLL-L] NXT batery warning

 

Agreed - always use fresh AAs. 

 

The recharchable batter has a goofy memory and the voltage drop will make reproducibility for missions almost impossible. 

Sent from my iPhone


On Oct 8, 2010, at 12:48 PM, Lloyd O'Hara <[log in to unmask]> wrote:

We only use batteries and always make sure we have plenty on hand.

 

Also, I'm sure why you would take 2 sets of four AA batteries, the nxt takes six AA..

 

Lloyd

----- Original Message ----- 

From: Viquar Shaikh <mailto:[log in to unmask]>  

To: [log in to unmask] 

Sent: Friday, October 08, 2010 10:50 AM

Subject: Re: [VADCFLL-L] NXT batery warning

 

To add to this --- no matter what - we always carry 2 sets of four AA batteries - one is a new packed set. This is a good backup for these 'just-in-case' scenarios.

 

Thanks

Viquar

On Fri, Oct 8, 2010 at 10:32 AM, Brandy bergenstock <[log in to unmask]> wrote:

This came across the Ga FLL yahoo group adn I thought it was important for everyone to realize:

The other day my team had taken one of their NXT bricks with them to a meeting.  When we got home, the battery was completely discharged. After recharging it, my  daughter discovered that the "Sleep" setting was at 60 minutes. The brick had  accidentally turned on during transport and since the sleep setting was so long,  it ran the battery down. We discovered that the 60 minute setting is the default for both the 1.26 and 1.31 firmware update. That is WAY too long!

If you have updated your firmware, you should check the sleep setting and change  it is a more reasonable time (perhaps in the 2-5 minute time frame). This way you won't accidentally run down your battery. I'd hate for someone to discover their battery was dead when they arrived at a competition.

To access the sleep setting on the NXT brick, go to:

Settings
Sleep
and then change the time with the arrow buttons

 

  _____  

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-ADMIN-L. Visit https://listserv.jmu.edu/archives/vadcfll-admin-l.html to subscribe. 





  _____  

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-ADMIN-L. Visit https://listserv.jmu.edu/archives/vadcfll-admin-l.html to subscribe. 

  _____  

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-ADMIN-L. Visit https://listserv.jmu.edu/archives/vadcfll-admin-l.html to subscribe. 

  _____  

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-ADMIN-L. Visit https://listserv.jmu.edu/archives/vadcfll-admin-l.html to subscribe. 


-- 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-ADMIN-L. Visit https://listserv.jmu.edu/archives/vadcfll-admin-l.html to subscribe.