Transcript Document

Beach Cities Robotics
FRC Team 294 Summer Academy
Batteries and Soldering
July 20, 2008
Rick Wagner, Mentor, Beach Cities Robotics
FIRST Team 294
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Batteries and Soldering Outline
Concepts:
• Batteries
• Types
• Characteristics
• Charging
• Soldering
• Theory
• Practice
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FRC Battery
 Lead-acid (H2S04) sealed motorcycle battery can supply
more than 40 amperes for two minutes
 Heaviest single component in the robot
 Wear safety glasses when charging and handling
 A battery explosion can ruin your whole day (and blind
you for the rest of your life)
 A shorted battery will heat up rapidly and explode
 Wear no rings or watches when handling batteries
 A short across a ring will heat it red hot: you will
lose your finger
 Unlike the VEX battery (Nickel-Cadmium, NiCad), a
lead-acid battery does not need “conditioning” to take
a full charge
 A Ni-Cad battery needs to be deep discharged before
recharging for a maximal charge
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2006 Battery
ES18 Mfr Spec
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AGM is “Active Glass Mat”
AGM Type Automotive Sealed Lead-Acid Battery
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NiCd Batteries
 The principal advantages of NiCd over other
rechargeable types is lower weight for a given quantity
of stored energy, good charging efficiency, small
variation in terminal voltage during discharge, low
internal resistance, and non-critical charging
conditions. (Wikipedia)
 Certain usage patterns may cause a "false bottom"
effect. Specifically, if the battery is consistently
discharged to the same level, then fully recharged, the
battery will eventually stop discharging on its own
upon reaching this threshold. (Wikipedia)
 When not under load or charge, a NiCd battery will selfdischarge approximately 10% per month. (Wikipedia)
 If the battery is going to be stored unused for a long
period of time, it should be discharged down to at most
40% of capacity (some manufacturers recommend fully
discharging, or even short-circuiting), and stored in a
cool, dry environment. (Wikipedia)
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Soldering
 Soldering is a process in which two or more metal items are joined
together by melting and flowing a filler metal into the joint, the
filler metal having a relatively low melting point. Soft soldering is
characterized by the melting point of the filler metal, which is
below 400 °C(800 °F). The filler metal used in the process is called
solder.
 Applications:
 Attaching electrical components to circuit boards
 Electrical wiring attachment
 Plumbing with copper pipes
 Food cans
 Rain gutters
 Automotive radiators
 Jewelry
 Joining stained glass
 Small mechanical parts
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Soldering Concepts
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Oxidation
Wetting
Capillary action
Flux
Electronic solder (63% tin, 27% lead (eutectic)) with
rosin core flux
 Unsoldering
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Soldering Techniques
 Wear safety glasses
 Make a good mechanical joint
first
 Solder provides permanent
corrosion protection
 Do not rely on solder to
provide mechanical integrity
 Tin the iron (apply solder), then
wipe off oxide on the wet
sponge
 Apply the clean hot iron tip to
the joint
 When the joint is hot, flow in
the solder to the joint, not to
the iron
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