Battery
Battery
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Batteries are made of a positive rod running the centre (anode), a negative casing (the cathode) and an electrolytic non-conductive substance separating the 2 in the middle.
Excellent portable DC power source
The voltage value is the potential difference between positive and negative sides.
Connection
Connection
Use batteries of same configuration and age; if not:
Possible charging problems and shorten battery life
Weaker cell causes imbalance
Excessive heat - Possible explosion
Note: Ensure to observe polarity
Remove batteries when no longer in use
Ampere-hour
Ampere-hour
Ampere-hour (AH) is a measurement unit for battery capacity.
It's the product of discharge current and time
E.g. A battery with a capacity of 1 AH will last for:
1 hour at discharge 1 A rate
2 hours at discharge 500m A rate
10 hours at discharge 100m A rate
Battery capacity is rating of how long a battery lasts at a given output current
Most common unit of measure is amp-hour rating--the usual way to evaluate a battery capacity and ideal battery life approximation.
Average capacity
Average capacity
If a battery has an average capacity of 1.5 V, 8000 mAh to 0.8 V, means 8000 mAh is available before the battery deteriorates to its cut-off voltage of 0.8 V.
A cut-off voltage is when a battery is fully discharged and any more cause damage/reduce lifespan.
E.g. If something needs 1.5 V and 8000 mA, I can run it for an hour before it discards.
If something needs 1.5 V and 1 A, I can run it for 8 hours.
If something needs 1.5 V 500 mAmps, it can run for 16 hours, etc.
Batteries in series and in parallel have different effect of Ah average.
Series connection
Series connection
Batteries in series is when a battery's negative terminal connects to another's positive terminal.
VT = voltage sum
IT is the same
Max output current for 2 batteries in series is the same as 1 battery.
E.g. Two 1.5 V, 8000 mA batteries in series:
Total output voltage = 3 V
Total current = 8000 mAh
Parallel connection
Parallel connection
Batteries in parallel is when a battery's negative terminal connects to another one's negative terminal; same for positive.
VT = individual battery voltage
IT = sum battery current
Maximum output voltage for 2 batteries in parallel is the same as 1 battery.
Max output voltage for two batteries in parallel is the same as 1 battery.
E.g. Two 1.5 V, 8000 mA batteries in parallel:
Total output voltage = 1.5 V
Total current = 1600 mAh
Battery pack
Battery pack
Laptop batteries use a series-parallel configuration to get power needs.
Battery pack is when four 3.6 volt, 2400 mAH Li-on batteries are placed in series and joined with another 4-battery set in parallel.
The four 3.6 volts in series makes 14.4 volts in VT, placed in parallel doubles the AHs from 2400 mAH to 4800 mAH.
Battery cells
Battery cells
Primary cell
Primary battery/voltaic/dry cells is a battery (a galvanic cell) used once and non-rechargeable unlike secondary cells (rechargeable battery).
Carbon-zinc: 1+ 1.5 V primary cells
(low AH)
Alkaline (most common)
Portable stereos, remote controls, clocks, flashlights
Lithium – 3 V (High AH), Long shelf life for high-current applications.
Lithium Ion (button batteries) for watches, hearing aids, greeting cards.
Secondary cell
Secondary cells (rechargeable cells or wet cells) can be recharged.
Lead-acid – 2.1 V secondary cells; high AH (up to
20 AH)
Can last for ~4 years before replaced
Nickel-cadmium – 1.15 V secondary cells (up to
5 AH)
OFten can last for 10 years before replaced
Nickel-metal hydride and Lithium ion are newer
replacements for Ni-Cd
– Smaller, lighter, higher AH than Ni-Cd
Safety
Safety
Never put the wrong type of battery in a charger.
Never put alkaline batteries whether rechargeable or not into a nickel or lithium battery charger. The batteries will overheat, on fire and explode.
Never mix up the nickel and lithium batteries in a charger
In a wet battery a short occurs between the
positive and negative side– it could overheat and may be on fire, leak acid/explode.
Disposal
Disposal
Regular alkaline non-rechargeable batteries
can be disposed of in regular household waste
(not recommended) provided you are not
disposing of a whole bunch of them. Many
places now will accept and dispose of the
batteries for you.
NIMH, Nicd and Nickel-Zinc can not be
disposed of in regular household waste.
Children
Children
[2] Chewing on a battery cause severe burns from its acid. For 9 Vbatteries, kids easily get a painful shock.
One of the most dangerous batteries for kids are button batteries (Lithium Ion), easily swallowed/choking hazard.
Acid inside cause severe burns and even death in young kids.
Button, coin, or watch cells
Button cell
Button cell
[1] Button cells/watch or coin battery are small batteries made of 1 electrochemical cell and shaped as a squat cylinder typically 5 to 25 mm (0.197 to 0.984 in) in diameter and 1 to 6 mm (0.039 to 0.236 in) high – like a button. Stainless steel often makes the bottom body and positive terminal of the cell; insulated from it, the metallic top cap forms the negative terminal.
References
References
Quizzes
Quizzes
[Q1]
[Q2]
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