Batteries
 Categories
 Primary Battery
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Can produce current immediately on assembly
Disposable
Used in low current drain or intermittently
Can NOT be recharged – the chemical reactions are not reversible and active materials may not
return to their original forms
Lose 8-20% of charge per year at 20-30oC
 Store at lower temperatures, but do NOT freeze
Types
 Zinc-Carbon
 Zinc-Chloride (Heavy Duty)
 Alkaline – Zinc-Manganese Dioxide
 Warning: container polarity reversed between old and new varieties
 Others – Nickel Oxyhydroxide, Li-CuO, LiFeS2, Mercury-oxide, Siver-oxide
 Secondary Battery
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Must be charged before use – assembled with active materials in a discharged state
Rechargeable
Cycle Types
 Starting Battery
 Thin plates designed to maximize surface area/current output
 Don’t discharge more that 20%
 Deep Cycle Battery
 Thick, heavy plates designed for repeated heavy discharges
 Designed for up to 80% discharge
Cell Types
 Wet Cell or Flooded Cell
 Lead-Acid Battery
 Plates surrounded by sulfuric acid electrolyte
 Positive - chocolate brown (Lead Oxide alloy)
 Negative – slate gray (Lead alloy)
 Separator
 Sulphation
 Produce Hydrogen Gas when charging
 Heavy
 Spills
 Sealed vs Vented
 Valve Regulated Lead-Acid Battery (VRLA)
 Flat plate or spiral
 Electrolyte is immobilized
 Gel Cell – semi-solid electrolyte
 Absorbed Glass Mat (AGM) - electrolyte in a special fiberglass matting
 Heavy
 Greater resistance to temperature, shock or vibration
 No need to keep upright
 Slower Discharge
 Longer life
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Dry Cell
 Nickel-Cadmium (NiCd)
 Lose 10% of charge in first 24 hours then 10% per month
 Rated for 1000 cycles
 Memory effect – crystals building up
 Discharge completely before recharging
 Environmental Hazard due to Cadmium
 Nickel –Zink (NiZn) – not commercially viable yet
 Nickel Metal Hydride (NiMH)
 Regular vs Slow Discharge
 Eneloop discharge at 15% per year
 Rated at 500-1000 cycles
 Lithium-Ion (Li-ion)
 Expensive
 High energy density – used in laptops, digital cameras, camcorders, cell phones
 Explodes if short circuited
 Molten Salts
 Uses molten salts as an electrolyte – hard to keep up to temperature
 Reserve
 Activated by adding electrolyte
 Impact breaking a capsule
 Sea water activated device
 Short service life after long-term storage
 Capacity – The amount of electrical Charge it can store
 Standard Capacity – The constant current a battery can supply for 20 hours at 68oF (20oC) X 20
 Example: A battery rated at 100 Ah will deliver 5 amps over a 20-hour period.
 Higher discharge rates deliver less energy
 Cold Cranking Amps – How much amperage can be supplied by the battery at 0oF for 30 seconds
before the battery voltage drops to 7.2 volts
 Charging
 Measuring Depth of Discharge (DoD)
 Specific Gravity (corrected for temperature)
 Load Testers
 Generally, for 6-cell Lead-Acid Batteries
 Open-circuit at full charge: 12.6v (2.1v per cell)
 Continuous-Preservation (Float) Charging:
 13.4v gelled electrolyte
 13.5v AGM
 13.9v flooded cell
 Precise float voltage is critical to longevity
 Insufficient voltage causes sulfation
 Excessive voltage causes corrosion and electrolyte loss
 Fast vs Slow Charge
 Quick charge only scratches the surface and can decrease the life of the battery
 Slow charge penetrates the plates further and is better for the battery
 Smart Chargers
 Desulfonators
 For wet-cell lead-acid batteries
 Pulse conditioning that breaks down the sulfate crystals on the plates
 Off-gassing
 When charging, a flooded battery gives of hydrogen gas – explosive
 Additives
 Epsom Salts – reduced the internal resistance in weak or damaged battery and may slightly extend
life
 EDTA – dissolves sulfate deposits in heavily discharged plates but the dissolved material is no
longer available to participate in the charge discharge cycle. It also forms organic acids which
accelerates corrosion of the plates and connectors
 Connections
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Terminal lugs
Copper
Spade
Andersen Connectors
 Maintenance
 Terminal Corrosion – Corrosion of the positive terminal is caused by electrolysis, due to mismatch of
metal alloys used in manufacturing
 Cleaning
 Sealing – Petroleum jelly or commercial sprays
 Clean up – Baking soda
 Charge Lead-Acid batteries every 6 months or when shows 70% capacity (charge)
 Charge NiCd and NiMH batteries at least once a year.
 Condition the battery (charge and discharge) before heavy use
 Avoid freezing but store in cool, dry place