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Q1. What is NiMH and what is a NiCd? What’s the
major difference between the two types of batteries?
Q2. How
much better are NiMH rechargeable
batteries compared to vs. NiCd rechargeable batteries?
Q3. How
much performance improvement can I expect using NiMH batteries?
Q4. What is
the Memory Effect of a NiCd battery? How can I avoid it?
Q5. Do NiMH batteries
have Memory Effect?
Q6. Are
the alkaline batteries better suited to some uses than NiMH rechargeable
batteries?
Rechargeable Battery
Technicals Answers
Q1. What is NiMH and what is a NiCd? What’s the major
difference between the two types of batteries?
Answer
NiMH
refers to Nickel Metal Hydride and NiCd refers to
Nickel Cadmium. The major differences between the two types of batteries
are is capacity, memory effect and environmental friendliness. NiMH
batteries have high capacity, no memory effects and environmentally friendly.
If you are under the illusion that rechargeable batteries are not very good
then the chances are that you have been using older Alkaline rechargeable
batteries (which are rubbish) or NiCd batteries suffering from memory effect
and you have not been aware of the effects of
Memory Effect.
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Q2. How much better are NiMH rechargeable batteries
compared to vs. NiCd rechargeable batteries?
Answer
NiMH
batteries are the results of recent technology advance. NiMH batteries last
much longer than NiCd batteries per charge. NiMH batteries also are
environmental friendly because of elimination of cadmium toxicity concerns.
Today, more and more high-drain devices consume battery power quickly.
Consumers will greatly benefit from the value proposition delivered by
NiMH. Not only do they deliver more power, lasting longer in high drain
devices, but they also can be charged up to 1000 times. NiMH batteries
are much better than NiCd batteries.
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NiMH batteries'
advantage over NiCd batteries |
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PERFORMANCE |
NiMH batteries will
greatly out-perform standard NiCd batteries in high-drain applications.
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CAPACITY |
The amount of energy
stored by the battery. NiMH has more than twice the capacity of standard
NiCd. NiMH batteries have much longer runs times (hours played,
number of
pictures taken). |
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MEMORY EFFECT |
NiMH batteries can
be charged or “topped-off” at any time without affecting battery life.
In order to achieve optimum performance from NiCd batteries, they must
be fully discharged before recharging. Unlike NiCd batteries, NiMH
has No Memory Effect. |
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ENVIRONMENTALLY
FRIENDLY |
NiMH batteries have
no Cadmium added. Cadmium is hazardous to the environment.
NiMH is
much more environmentally friendly |
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VOLTAGE |
The power produced
by the battery. Both NiMH and NiCd have virtually the same voltage.
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Comparison between NiMH and NiCd rechargeable batteries
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|
NiCd |
NiMH |
|
AA Capacity
(mAh) |
600 - 800 |
1,800 –
2,000 |
|
AAA Capacity
(mAh) |
200 |
600 -
700 |
|
Service Life |
Up to 750 cycles |
Up to
1,000 cycles |
|
Voltage |
1.25V
|
1.25V |
NiCd
batteries can generally perform well in devices such as TV controls, clocks,
radios or torches for example, where they will happily operate until they
run flat. Modern power hungry devices like digital cameras, video cameras or
remote control toys on the other hand are better suited to NiMH.
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Q3. How much performance improvement can I expect using NiMH batteries?
Answer
NiMH rechargeable batteries will easily outperform throwaway alkaline
batteries. Have you ever noticed that when using high
powered
alkaline throwaway batteries in your
digital camera
that things can soon start to slow down and you eventually need to replace
the batteries a lot sooner than you'd like to?
DO NOT throw these batteries away (well not yet!) as you will probably find
that they will work perfectly satisfactorily in less demanding equipment
such as radios or TV controls. The battery still has plenty of power but is
no longer able to deliver it quickly enough. That's why everything stutters
and slows down. It does not matter which make of alkaline battery you try to
use as there is no getting away from the fact that alkaline batteries are
quite simply not capable of operating today's power hungry digital devices
due to the outdated chemistry of alkaline batteries. Alkaline batteries can
store the power, it's just that after a relatively short period of use, they
simply can't delivery it quickly enough in modern digital equipment when
full power is required “in a flash”.
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Q4. What is
the Memory Effect of a NiCd battery? How can I avoid it?
Answer If a NiCd
battery has not been entirely emptied before the next charge, the charge
will not be complete and will set a new lower energy capacity. Over time it
will appear that the battery is no longer holding a charge. This is called
the "memory effect". To avoid this, it is best to occasionally
discharge
NiCd batteries entirely as this will ensure optimum performance and help
lengthen the life of the battery. You should discharge
NiCd
cells before every fifth to tenth process of charging in order to avoid the
feared memory effect. The memory effect has the consequence that the not
used parts of the cell due to partially discharging are no longer in a
position to receive and produce energy. Consequently their operating times
become shorter and shorter and the cells have to be recharged more
frequently. This often misunderstood feature of NiCd batteries has possibly
given some users a bad impression of rechargeable batteries in the past.
NiMH batteries don not have memory effect.
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Q5. Do NiMH batteries
have Memory Effect?
Answer
NiMH batteries have no memory effect.
Memory is a type of problem that traditional NiCd batteries usually
develop. You probably have heard that in order to maintain the life and
performance of rechargeable batteries, you have to fully drain the batteries
before recharging them. Thanks to "memory free" technology used for NiMH
batteries, you can charge them anytime you wish, regardless if the batteries
are fully drained or not.
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Q6. Are
alkaline batteries better suited to some uses than NiMH rechargeable
batteries?
Answer
This
really depends on what you are using the batteries for. For most high drain
electronic devices, like digital cameras, rechargeable batteries will
continue to work much longer than alkaline batteries. In fact in devices
like digital cameras, NiMH batteries will run on a single charge for 3-4
times as long as they would on an alkaline battery. Alkaline batteries can
be the better choice than NiMH or NiCd for some uses. Alkaline
Batteries are more suitable for use in low-energy consumption appliances
like digital clocks or remote controls. Rechargeable NiMH
batteries are the better choice for high drain applications. They lat much
longer on a single charge and don’t have to be discarded after a singer use.
Alkaline batteries are comparatively very expensive.
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