Post on 15-Jan-2016
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Beach Cities RoboticsFRC 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 BatteryES18 Mfr Spec
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AGM Type Automotive Sealed Lead-Acid Battery
AGM is “Active Glass Mat”
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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 self-discharge 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
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