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Battery
FAQ |
| Q: What is
the difference between NiCd and NiMH Rechargeable Batteries? |
Both NiCd and NiMH batteries are rechargeable.
The main difference between the two is the fact that NIMH
batteries offer higher energy densities than NiCads. In
other words, pound for pound, NIMH delivers approximately
30% more capacity than its NiCad counterpart. What this
translates into is increased runtime from the battery with
no additional bulk. NIMH also offers another major advantage:
NiCad batteries tend to suffer from what is called a "memory
effect". What this means is that when a NiCad battery
is only partially discharged before charging, the battery
"forgets" that it has the capacity to further
discharge all the way down.
To illustrate: If you, on a regular basis,
fully charge your battery and then use only 40% of its capacity
before the next recharge, eventually the battery will become
unaware of its extra 60% capacity which had remained unused.
Your battery will remain functional, but only at 40% of
its original capacity.
The way to avoid the dreaded "memory
effect" is to fully cycle your NiCad battery at least
once a month. In other words, fully discharge your battery
and then fully charge it.
Batteries can be discharged by allowing the
device to run on the battery until it ceases to function.
This will insure your battery remains healthy. NIMH batteries
are "memory free" - they do not suffer from this
affliction. Thus, if you have a NIMH battery, the only time
it is necessary to cycle it is during its initial use and
after a long storage period. This is done to "exercise"
the battery and bring it up to full capacity.
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| Q: Battery
symbols and terminologies explanation. |
"mAh": Stands for milli-ampere
hours. It measure the capacity of the batteries. For example,
a 1000mAh capacity means that the batteries will last for
1 hour if subjected to a 1000mA discharge current.
"V": Stands for voltage. It measure the
power of the batteries. For Ni-MH batteries, they are 1.2V.
For alkaline batteries, they are 1.5V.
"C": defines the rate at which
a battery is charged or discharged. It is the capacity obtained
from a new battery subjected to a constant-current discharge
at room temperature.
| Zn-MnO2 Battery |
IEC Type |
Type in USA |
Type in Japan |
Dia(mm) |
Height(mm) |
In Chinese |
| Normal |
R03 |
AAA |
UM-4 |
10.5 |
44.5 |
Battery #7 |
| R6 |
AA |
UM-3 |
14.5 |
50.5 |
Battery #5 |
| R14 |
C |
UM-2 |
26.2 |
50 |
Battery #2 |
| R20 |
D |
UM-1 |
34.2 |
61.5 |
Battery #1 |
| Alkaline |
LR03 |
AAA |
AM-4 |
10.5 |
44.5 |
Alkaline Battery #7 |
| LR6 |
AA |
AM-3 |
14.5 |
50.5 |
Alkaline Battery #5 |
| LR14 |
C |
AM-2 |
26.2 |
50 |
Alkaline Battery #2 |
| LR20 |
D |
AM-1 |
34.2 |
61.5 |
Alkaline Battery #1 |
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| Q:
What are some types of batteries? |
A: A few types of batteries are: Sealed
Lead Acid Battery, Flooded Lead Acid Battery, Ni-Cad (NiCd)
Battery, Alkaline Battery, Silver Oxide Battery, Lithium
Battery, Mercury battery, Manganese-Dioxide Battery, Zinc-Air
Battery, and NiMH Battery.
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| Alkaline Battery FAQ |
Q:
What is alkaline battery? |
A: Alkaline
battery standards household battery series. It is used in
products from walkmans and clocks, to smoke detectors and
remote controls. Since 1994, most types of alkaline batteries
contain no added mercury or only contain trace amounts.
These kinds of alkaline batteries are marked "no added
mercury" or have a green tree logo.
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What's
the difference between alkaline and carbon-zinc batteries? |
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Better discharge rate capability,
lower and more stable internal resistance
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Better low temperature
performance and service maintenance
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Higher energy density
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More economical in terms
of cost per hour of use on high current drains
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Sloping discharge curve
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Relatively insensitive
to changes in the discharge rate or duty cycle
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Available in voltages ranging
from 1.5 to 12.0 and a variety of shapes and sizes
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Q:
What's the difference between alkaline and rechargeable batteries? |
Capacity:
Typical NiMH (Nickel Metal Hydride) Rechargeable AA cells
have a capacity ranging from 1300mAh to 1600mAh; the higher
the figure, the more energy it stores. Alkaline AA’s
usually have a capacity of 2800mAh, so initially it appears
that alkaline batteries can last longer. In addition to
capacity, however, an additional critical criteria that
affects both battery performance and run time is the energy
rating, or discharge characteristic, of the appliance.
Discharge Characteristic: Alkaline battery is very
different from rechargeable batteries in this aspect. The
voltage of an alkaline battery will drop linearly from 1.5V
to about 0.7V, and then cut off, while a rechargeable battery
will deliver 1.2V to 1.0V output constantly, then cut off
sharply when it drops to 1.0V (or when 90% of its energy
is released). Due to this, alkaline batteries are more suitable
to use in low-energy consumption appliances like radio alarms
or remote controls, which voltage drops from 1.5V to 0.7V
steadily. Rechargeable batteries are most suitable for high-energy
rated appliances like digital cameras or racing cars.
Memory Effect: affects the run time of a traditional
(NiCd) rechargeable battery. The term refers to the process
in which the battery will stop delivering stored energy
before it is really fully drained. This usually happens
in NiCd rechargeable batteries only. If a NiCd rechargeable
battery has been repeatedly recharged before it was fully
used up, this will cause a chemical change inside the battery,
which stops energy delivery early. If memory effect occurs,
simply use up the battery and the battery will recover itself.
NiMH Rechargeable Batteries do not have Memory Effect.
Self-Discharge: When a battery is put aside for
a period of time, it will lose its stored energy. Alkaline
battery can hold 80-90% of its charge up to a few years.
For rechargeable battery, most of its charge will be gone
after six months and the battery will need to be recharged.
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| Q: Why
do my alkaline batteries run down so quickly when used in a
digital camera? |
A: Alkaline batteries were
not designed to meet the very high power demands of today's
electronic devices. Alkaline batteries have a high rated
capacity, but they can only deliver their full capacity
if the power is used slowly. Electronic devices such as
digital cameras place a high power drain on batteries, so
it is much better to use rechargeable NiMH or NiCd batteries
for these type of devices. Lithium batteries also work well
in high drain applications but they are expensive and are
not designed to be recharged.
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Q: Can NiMH batteries
be substituted for alkaline batteries even though they are
only 1.2V? |
A: Yes, for most high drain
electronic applications NiMH batteries are ideal substitutes
and you needn't worry about the apparent voltage differences.
Even though alkaline batteries are rated at a nominal 1.5V,
they only deliver 1.5V when they are fully charged. As they
begin to discharge the voltage of alkaline batteries continuously
drops. In fact, over the course of their discharge, alkaline
batteries actually average about 1.2V. That's very close
to the 1.2V of a NiMH battery. The main difference is that
an alkaline battery starts at 1.5V and gradually drops to
less than 1.0V. NiMH batteries stay at about 1.2V for most
of their discharge cycle.
Here are a couple of cases where there actual voltage difference
may be important to you. In the case of a device like a
radio, where a higher voltage can mean a stronger signal,
a fresh alkaline battery may be more desirable -but more
expensive- than a rechargeable NiMH battery. This is also
true for a flashlight, which will be brighter with the initial
higher voltage of alkaline cells. These minor difference
may not be important to you and are probably offset by the
much lower cost of operating NiMH batteries. And keep in
mind that the alkaline battery only has a higher voltage
when it is fully charged. Once it gets to 50% capacity or
less, it will be delivering a lower voltage than a NiMH
battery.
The one time when the voltage differences of the two is
important is in the case of a device checks the voltage
of a battery to estimate the amount of charge left on the
battery. Because the voltage of an alkaline battery drops
at a very predictable rate it's possible to estimate the
amount of capacity left in an alkaline battery based solely
on its voltage. (1.5V/fully charged, 1.25V/50% charged,
1.0V/almost fully discharged). But a NiMH or NiCd battery
stays at about 1.2V until it is nearly completely discharged.
This makes it almost impossible to know the amount of capacity
left based on its voltage alone.
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