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Battery Tips
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1.Alkaline Batteries:
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Zinc-Manganese Dioxide, primary cells. Widely available, superior to Zinc-Carbon
batteries. Special versions are available that will take a limited number of recharges.
1.5 volts, fairly high internal resistance.
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2.Battery:
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A device for making or storing electricity chemically. Electricity is a form or
energy that is easy to control, convenient to use but difficult to store. A can
of petrol contains 10,000 times the energy of a car battery. Hence the difficulty
in making an electric car with a good performance.
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Penguin is one of the well known names in the field of consumer electronics, information
technology, telecommunications, office automation and entertainment in the UAE and
caters to all the seven emirates of UAE.
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3.Battery Pack:
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A rechargeable pack of batteries that can be clipped and unclipped to a battery-driven
tool. It is usually possible with reasonable ingenuity to open a battery pack and
replace the cells inside.
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4.Burglar Alarm Battery:
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Most burglar alarms contain a battery as back-up in case the electricity supply
is cut off. This is usually a Sealed Lead Acid Battery wired so that it is automatically
recharged. It will need replacing every 5/10 years.
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5.Capacity:
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This is stated as the size of current (amps) that the battery will produce over
a rated time (hours). Measured in mAh, (milliamps x hours) or, 1000 times bigger
Ah, (Amp x hours) . This rating is usually lower if a battery is asked to produce
a large current (i.e. if the battery has to work fast it will usually produce a
little less useable energy). Note that 10 Ah at 12 volts is twice the energy of
10 Ah at 6 volts. The measure of energy stored by a battery is Volts x Amps x Hours
or Watt.hours.
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6.Cell:
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One battery unit. Originally, cells were connected into a battery of cells to make
a battery. A 12 volt car battery is made of 6 x 2 volt cells connected in series.
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7.Charging:
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Charge batteries with a DC current, positive terminal to positive terminal. The
voltage must be greater than the battery or battery pack voltage. The current must
be limited and the current cut off when the battery is fully charged. Full charge
is sensed either by a rise in voltage, a rise in resistance or a rise in temperature.
Battery chargers are designed to supply a suitable current for the batteries with
which they where designed to work. Unless chargers are labeled otherwise, remove
the battery after 16 hours. More sophisticated chargers will switch to a trickle
when they sense the battery is fully charged. This is fine for Lead-Acid batteries
but NiCd and NiMh should not be left on ‘maintenance’ charge for more than a few
days. As a rule of thumb, the charging current is one eighth of the Ah (in Amps)
or mAh (milleamps) rating of the battery. A full charge takes about 1.4 times the
label capacity.
E.g. NiMh Battery 1800mAh capacity Charging current 1800 divided by 8 = 225 mA Charging
time 1800 divided by 225 x 1.4 = 11.2 hours
At no time should the temperature rise much beyond blood heat.
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8.Current:
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The rate at which (a volume of) electricity moves through a (pipe) conductor. Measured
in Amps. The potential is measured in (height) volts. The Voltage (or height) difference
is a measure of how painful the shock (or how hard the knock is if you fall.) With
batteries, unless it is a long series, the voltage is too small to feel but the
current is often large. A torch bulb takes 10 times the current of a domestic light
bulb. Therefore the connections have to be more than 10 times as good, as any weakness
makes a much bigger loss due to the low voltage to start with. Clean contacts with
a pencil rubber, a little Meths if necessary. Abrasive paper is a last resort as
the contacts will originally have been plated and the exposed metal will quickly
corrode. If you are faced with a bad contact and are willing to try some humble
botching, reform the contact by 'tinning' with solder. It works to a reasonable
degree - usually. Due to the high currents, joints - and soldered joints - must
be good. Wires must be short and heavy.
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9.Disposal:
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Never burn any battery. It may explode, it will release caustic electrolyte, and
it may distribute harmful metal oxide particles.
Batteries containing:
- Lead
- Silver
- Cadmium
- Mercury
- must have special disposal.
Reputable scrap metal dealers will often accept Lead batteries. Lithium batteries
containing more than 0.5gram of Lithium metal (larger than sold by LowCostBatteries)
present a special hazard. Alkaline, NiMh, Zinc-Air, small Li-ion and Lithium coin
cells, and conventional torch batteries can go in domestic waste in the US.
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10.Electrodes:
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The raised Positive pip on a torch battery is connected to the battery Cathode;
the flat end is connected to negative Anode. In a Lead-Acid battery -car battery-
Lead is the anode and acid -sulfuric acid, battery acid- the electrolyte. Lead Dioxide
is the cathode. In a NiCd, Nickel-Cadmium, battery Nickel is the anode and Cadmium
the cathode.
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11.Electrolyte:
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The conducting stuff between the 2 electrodes of a battery. Usually a bit of water
and a lot of nasty chemicals. In a dry cell to make things civilized, the electrolyte
is made into a paste that won’t pour, absorbed onto a mat and then sealed in a container.
Don’t puncture the container.
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12.Fish:
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Fish are very sensitive to low voltages. This fact is used in electric fishing.
6 volts is lethal to a large fish. Aquarium owners be warned.
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13.Fuel Cell:
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A battery that makes electric current from mechanically or continually replaced
electrodes. E.g. Hydrogen/ oxygen cells proposed for electric cars. Not generally
available off-the-shelf. Instead of burning the fuel to make heat, the fuel cell
makes electricity.
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14.Hearing Aid batteries:
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In some hearing aids you can also use Silver-Oxide batteries. Silver-Oxide batteries
are more expensive and have less capacity but they don’t self-discharge. If you
use a hearing aid only occasionally, they might be worth considering. By international
agreement the size of hearing aid batteries is identified by the color of the self
adhesive tab.
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15.Internal Resistance:
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When a battery is connected to a circuit to do work, the current in the circuit
is in inverse proportion to the resistance of the circuit plus the internal resistance
of the battery. This can lead to the batteries becoming warm. If they become hot
- any more than blood heat -switch off! They are being asked to do too much work.
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16.Li-Ion Batteries:
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Rechargeable batteries often seen in mobile phones. 3.6 volts per cell. Lightweight,
high capacity, believed memory free. Relatively high price. Not that much difference
in capacity for the same volume as NiMh, but significantly lighter. Li-Ion batteries
can be 'Top Up' charged- recharged at any convenient time, without waiting for the
battery to be completely discharged. For storage- store them as they are and allow
them to self discharge slowly. Recharge them fully again when you want to use them.
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17.Lithium:
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The third element, after Hydrogen and Helium. This position at one of the extremes
gives it some interesting properties. It makes very good batteries but put water
on it and you’ll start a fire! Very different types of battery are made containing
Lithium; some are rechargeable some are not; some are safe, some are not. Lithium
batteries sold by LowCostBatteries.com (and other general distributors) are safe,
used properly. (There are industrial Lithium batteries that need special handling,
transport and storage – briefly, these contain more than 0.5gram of metallic lithium
per cell)
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18.Lithium Coin or Button Cells;
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LowCostBatteries.com sell Lithium-Manganese Dioxide coin cells. Zinc-Manganese Dioxide
-Alkaline- cells are made in the same sizes. The Lithium cells have a larger capacity
and voltage. Often interchangeable. Not rechargeable. Never try to recharge. 3 to
3.6 volts nominal per cell. Less than 0.5 grams Lithium per cell. Probably inside
the key fob that lets you into your car. Better tolerance of temperature extremes
than other domestic batteries. -50 Deg. C to +70 Deg. C. Long shelf life -10years+
Long life in low drain service -in your key fob.
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19.Magnesium Battery:
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Magnesium batteries are used in sea going safety equipment. They are made without
an electrolyte. When immersed in sea water, the salty water acts as an electrolyte
and they produce power. They have a good, but finite, shelf life even in humid conditions.
Once activated they must be replaced.
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20.Memory Effect:
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Some rechargeable batteries are said to have a memory. If they are part-used and
recharged before the whole charge is used up, they ‘remember’ this and next time
will only use that part of their capacity. Therefore part of their capacity is lost.
This is the theory, it is much debated. NiCd and NiMh batteries are said to suffer
from memory effect. NiCd and NiMh batteries prefer complete cycles; fully charge
then use until empty, do not recharge before storage - allow them to self-discharge
during storage. In the real world, either of these batteries will accept less than
the ideal and provided that they are recycled completely, full to empty, reasonably
often they will put up with what comes in between. NiMh batteries have less memory
effect than NiCd. In my workshop, where batteries are treated as workhorses, with
only a moderate amount of care, NiCd batteries out-last NiMh batteries. This is
because NiCd batteries under reasonable conditions, will take more charge/discharge
cycles.
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