|
MAHA
New Generation Nickel Metal Hydride Batteries |
Traditional
Nickel Metal Hydride Batteries |
Nickel
Cadmium Batteries |
Memory
Effect
(Do
you have to fully drain the battery before
recharging) |
None |
None |
Yes |
Capacity
(How long a battery will last) |
1800mAh
(AA) |
1300mAh
to 1600mAh |
600mAh
to 1000mAh |
Ability
to accept trickle charge
(Can you leave batteries in the
charger) |
Yes |
No |
Yes |
Life
cycles
(How many times can you recharge the
batteries) |
500-1000
cycles (Depends on discharge & charge
rate) |
250-500
cycles |
500-1000
cycles |
| Environment
Problem |
None |
None |
Yes.
Highly toxic |
Discharge
Characteristics
(How well does the battery hold up
when used in a high drain device) |
Remain
above 1.2v/cell at 1C discharge curve during
80% of usage. Click
here for details. |
Remain
above 1.2v/cell at 1C discharge curve during
80% of usage |
Remain
above 1.2v/cell at 1C discharge curve during
45%-50% of usage |
* Cell information and
specification varies from brand to brand
Q:
I
have not used my NiMH batteries in several months and
they are not holding their charge. How can I fix this?
NiMH batteries will
self-discharge if left unused. Generally, within 30 to
60 days, batteries will become completely drained. When
using them, you will need to first recharge them. After
extended storage, you may need to condition (using the
conditioning feature on PowerEx chargers like the
MH-C204F) the batteries several times to regain nominal
performance.
Q:
I
plan to use the MAHA NiMH batteries as a backup power.
How long will they hold their charge?
This
is commonly referred to as the "shelf life" of
batteries. For MAHA NiMH batteries, the shelf life at
room temperature is about 70 to 90 days (for those who
are a bit more technical, take a look at the charge retention
curve). If you are seeking for longer shelf life,
you may wish to consider alkaline or non-rechargeable
lithium batteries, which are commonly used for memory
backups.
Q:
Explain
the various battery symbols and terminologies.
"mAh":
Stands for milli-ampere hours. It measures 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 NiMH batteries, they are 1.2V. For
alkaline batteries, they are 1.5V.
"C": "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. For
example, draining a battery at 1C means to drain the
capacity of a cell completely in one hour. Likewise,
draining a battery at 0.2C means discharge a battery in
5 hours. For nickel-metal hydride cells, the rated
capacity is normally determined at a discharge rate that
fully depletes the cell in five hours, or 0.2C.
Q:
I recently received
a dozen AA NiMH batteries that I ordered from
you. Today I put four of the batteries
in a charger for the first time. The charger came with
my Olympus digital camera, and was made by Olympus
specifically for NiMH batteries. I was startled to find
that as the batteries charged they got almost too hot to
hold. I know that with other types of batteries, ANY
perceptible heating during charging is a sign of
possible battery damage. I wonder if you can shed any
light on what is happening here. Is my charger
defective, or badly designed, or is this normal for NiMH
cells?
This is pretty much normal. NiMH batteries can reach as
high as 130 degrees during a charge cycle as pointed out
by MAHA Energy. The amount of discharge and of course
the rate of charge will affect this.
This is why we recommend the following
1. Do not close the cover ( if your
NiMH Battery Charger has one ) while your batteries are
charging. It is best to allow any heat to dissipate as
much as possible.
2. You also may wish to use a small fan to help keep the
batteries cool, and prevent excessive heat build up
during charging.
Q:
Do
NiMH batteries really require a special charger (other
than those designed to recharge Ni-Cd batteries, or is
that just a marketing ploy by the manufacturers of the
chargers? I looked at a charger that has separate
settings for both Ni-Cd and Ni-MH batteries, and it
appears that the mA output is the same for both
settings.
Newer NiMH battery chargers are
designed to specifically charge NiMH and NiCD
chemistries. However most of the older NiCD chargers
were not designed to charge any other battery
chemistries such as NiMH since they were unavailable at
that time these chargers were designed. That is why many
of the newer NiMH/NiCD chargers are capable of
automatically charging both types, while others have a
switch. There is more than just mA ratings involved when
charging different battery chemistries (rate of charge,
length of charge, type of charge. etc...) While it is
true that some NiCD chargers can be used to charge NiMH
batteries you must consider the following points if you
decide to attempt to charge your NiMH batteries using an
older NiCD charger.
1. Improper charging or using a
charger that is not specifically designed to charge any
rechargeable battery can cause their useful life to be
shortened dramatically or in some cases actually damage
them permanently. We have even had some individuals
attempt to charge rechargeable alkaline batteries in
some of our chargers and were surprised when they
exploded.
2. Although a NiCD charger may seem to
be charging NiMH batteries fine, this is not usually the
case. NiMH chargers are specifically designed to prevent
Hydrogen bubbles from forming on the battery plates and
of course to charge them to their full potential.
Basically you should always use the
type of charger recommended for your type of batteries. |