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Unread 08-01-2003, 08:22
Unsung FIRST Hero
Al Skierkiewicz Al Skierkiewicz is offline
Broadcast Eng/Chief Robot Inspector
AKA: Big Al WFFA 2005
FRC #0111 (WildStang)
Team Role: Engineer
 
Join Date: Jun 2001
Rookie Year: 1996
Location: Wheeling, IL
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Quote:
Originally posted by Nataku
last year we lasted 3 minutes on a battery before we started noticing slowing down and the low batt light, and this year we are able to draw 120A, so i highly advise changing after every match
Don't be fooled by the statistics. The 120 Amp circuit breaker needs to be derated when periodic currents over 120 amps are drawn. Putting a demand on the battery of periodic bursts above about 200 amps will cause the breaker to trip in about 15 seconds.
Although our batteries are rated at 18 Amp Hour that really means they are designed to deliver 0.6 Amps continuously for 20 hours before the terminal voltage falls to to a specified voltage.
And yes, the battery is able to supply currents for short periods of time, well in excess of 200 amps. That is why it is so important to store, charge and mount batteries with caution. 200 amps flowing through a dropped tool or wire is capable of causing high temperatures resulting in burns or other injuries. All electrical teams should stress safety when working with the battery and other high current components.
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Good Luck All. Learn something new, everyday!
Al
WB9UVJ
www.wildstang.org
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Storming the Tower since 1996.