Thread: Batteries~
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Unread 09-03-2011, 18:40
Dale(294engr]'s Avatar
Dale(294engr] Dale(294engr] is offline
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FRC #0294 (Beach Cities Robotics)
Team Role: Engineer
 
Join Date: Jan 2004
Rookie Year: 1998
Location: Redondo Beach, CA
Posts: 92
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Re: Batteries~

When 5A Quick Charge lamp goes out it is ~80% charged

Time to get there depends on the degree of discharge, batt age, temp
(SLA batts should ALWAYS be on charge to prolong life maintain lowest internal resistance = max delivered performance)

the 20% balance occurs in trickle mode usually ~.1A so takes 2-3hours..

Responding to earlier commenter. Quick charge does NOT reduce battery life
that's why it is programmed to cut off early (charge heating is culprit)
Battery life can be greatly extended (years) by charging ASAP after each use and remaining on trickle at all time

good news full top off is rarely needed
unless your robot draws above average current during 2m15s match
due to lots of robot pushing.. or inefficient drive train

cant have too many SLA's..
I advise my team to save least 1 Batt that had a full overnight trickle
for critical playoff use expect pushing matches of extra speed power

I will be RI at SanDiego & will bring Flash Drive with my Battery Workshop
I have Dynamic Battery Discharge curves that illustrate V vs I for constant load ~50A (18AH is valid only at .8A, at 50A it is a 6min batt! before the Vout drops quickly)
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