Battery Types, Tips & Technology
Battery technology have evolved greatly in the past few decades. Batteries may be constructed using one of several available composition technologies. Below is an explanation of the popular rechargeable and non-rechargeable battery technologies offered by Garden State Battery. Click a heading below for more information.
Battery Terms
Amperage/Amp Hours (Capacity)
Cell
Charge
Conditioning
Cycle
Discharge
MemoryEffect(voltage depression)
Rechargeable Battery Types:
Sealed Lead Acid (SLA) or "Gel Cell"
Nickel-Cadmium or (NiCd) or "Nicad"
Nickel-Metal Hydride (NiMH)
Lithium Ion
Battery Care and Handling
Overview
Sealed Lead Acid (SLA) or "Gel Cell"
Nickel-Cadmium or (NiCd) or "Nicad"
Nickel-Metal Hydride (NiMH)
Lithium-ion (LiIon)
Battery Charging Technology
Charging Methods
Analyzers & Conditioners
Battery Terms
Amperage/Amp Hours (Capacity) (Ah) (mAh = Milliamp hours, or 1/1000
amp per hour)
Represents the amount of energy a battery can hold at the rated voltage.
This measurement helps determine how long the battery will power the equipment
it is used in. Generally speaking, the more 'Ah's,' the longer the run
time. A device which consumes 100mAh per hour will run about 10 hours
on a 1000mAh (or 1Ah) battery.
Cell
A single battery cannister. Usually grouped together with other cells to
form battery packs of different voltages. Example: six 1.2 volt cells
group together in series in a battery pack results in a 7.2 volt battery.
Charge
The process of putting energy into a battery. Required when battery
voltage falls below an allowable threshold.
Conditioning
The process of repeatedly charging and deep discharging a battery for the
purpose of preventing voltage depression or "memory effect" or to
otherwise restore lost capacity.
Cycle
The process of charging and discharging a battery, either through normal use of
by a conditioner.
Discharge
The release of energy by the battery.
Memory Effect (voltage depression)
The term used to describe the capacity loss and subsequent voltage drop in a
battery due to constant or repetitious charging and incomplete
discharging. This results in a loss of run time.
Rechargeable Battery Types
Sealed Lead Acid (SLA) or "Gel Cell"
Sealed lead acid or gel cell batteries came about around the early 1960's. This neat
invention surfaced from the problems that arose from regular flooded lead acid
batteries or wet cells. Wet cells would leak and could only be used in certain
positions (upright-like your old car
battery). German researchers were the first to develop the electrolyte gel in
which the battery acid was suspended in a gel. Then by sealing the battery with
the new gelled-electrolyte, you have the basis for the modern
"gel-cell" of today. Since the batteries are sealed, and valve
regulated for venting, they are relatively leak-proof and can be used in just
about any position with out leaking. Today’s gel-cells are very reliable and
used for hundreds applications from toys to millitary equipment. You may be familiar with them in your emergency lights, liteboxes, UPS's
etc. The only downside to gel cells is that their weight and size makes them
impractical for most communications devices where size and weight are important.
Nickel-Cadmium or (NiCd) or "Nicad"
Believe it or not, the nickel-cadmium battery formula is over 100 years
old! They have seen more than 50 years of successful use. They may
be recharged many times, are very tolerant of all types of abuse and are able to
deliver power over a very wide temperature range. Furthermore, they are
extremely economical. Nicad cells are often combined to make the battery
"packs" that are power portable 2-way radios, or "Walkie
Talkies," cordless tools, radio-controlled cars, razors and countless other
devices.
Nickel-Metal Hydride (NiMH)
We've had our customers ask for "Nickel hydroxide" batteries many
times; whatever you call them, nickel-metal hydride represents an evolution of
nickel-based battery technology. They pack considerably more punch per
pound than their NiCd cousins; NiMH batteries will run your two-way radio up to
40% longer than NiCd's, without adding to the weight. Furthermore, they do
not contain cadmium and are therefore more environmentally friendly. Quite
often, we are able to provide NiMH-based battery packs for the same price as
nicads. Perhaps the most significant feature of NiMH's is that they are
resistant to the "memory effect" that often presents a problem with
NiCd's
Lithium-ion
Lithium-ion cells are considered to be the latest technology used in
mass-produced rechargeable battery packs. First made commercially
available in 1991, they offer the highest
power-to-weight/size ratio of any of the popular rechargeable battery types
available today. They are also higher in voltage than NiCd and NiMH
batteries, which means less cells are required to meet the voltage requirement
of the device being powered. Add to that zero memory and a long service life and you
have a battery pack that is able to meet the demands of today's most popular
devices, such as digital cameras, laptop computers and portable music players.
Battery Care and Handling
Overview
As opinions vary widely as to the best care and handling methods for
rechargeable batteries, there is no "definitive" convention
available. We have therefore compiled our own set of guidelines for
battery care and handling, which are based both on our many years of experience
and on the research of notable battery industry professionals.
Sealed Lead Acid (SLA) or "Gel Cell"
Gel Cell batteries do not like to be fast charged. Fast charging causes them to heat up excessively, which
causes the
release of hydrogen and oxygen (also know as
" venting" or "gassing"). This release causes the electrolyte gel to dry up. Gel cells generally like a steady charge rate of about one tenth of
their rated capacity or “C/10”. As a general rule of thumb, you should not charge a gel cell at more than 25%
of its rated capacity. The optimum charging for a gel cell would be to charge at 25% or C/4 for about 80% of its
capacity, then switch to a slower rate, or "float" for the final 20% of capacity, preferably C/10.
Gel Cells do not
develop “memory” like their nickel cadmium cousins, so conditioning, analyzing or deep discharging is not necessary and will actually diminish the
useful life of the battery. Keeping a gel cell in a discharged state for extended periods will also diminish
its life. Storing in a cool, dry place will maximize shelf life.
Nickel-Cadmium or (NiCd) or "Nicad"
NiCD battery "packs," such as those used in 2-way radios, are very durable and require minimal maintenance, however, correct charging methods can greatly increase their performance and overall
life. We recommend that you first slow charge batteries which have been stored
for an extended period prior to placing in service. This initial charge
(usually at a rate of about 10% of the battery's rated capacity or
"C/10") is primarily to redistribute and even the distribution of chemical crystals that form on the battery plates that may have settled during extended storage.
New NiCD and NiMH batteries will not reach peak performance until 2-3 cycles of regular use have been
achieved.
Today’s NiCD batteries can be fast charged. The trick, however, is to know when to stop the charge, as overcharging causes overheating, which can damage a battery. There are many chargers available which monitor battery states and safely charge NiCD's (see Battery Charging Technology). NiCD batteries self discharge in storage or non-use at roughly 1% per day. So remember to fully charge your battery after extended periods of non-use. Charged batteries should be stored in a cool dry place when not in use. NiCd's are prone to develop memory effect (see definition above). Memory effect can be relieved by conditioning or deep discharging your battery. If a conditioner is not available, just try to discharge your battery as much as possible through normal use before recharging. It is normal for NiCD batteries to generate heat during charging however they should not heat up to the point where they cannot be handled. They should be allowed to cool down prior to being put into service.
Nickel-Metal Hydride (NiMH)
Since NiMH batteries are chemically similar to nickel-cadmium batteries, the
same charging and handling rules apply with one major exception: NiMH batteries
do not normally require conditioning. If your batteries are exhibiting
memory effect characteristics, conditioning may help restore lost capacity.
Lithium-ion
Lithium-ion batteries do offer obvious advantages over their predecessors, but
do not last quite as long. While nickel-based batteries have been known to
last many years in service, LiIon batteries may require replacement more
often. One reason laptop batteries have a high rate of failure is that
LiIon cells' life is shortened considerably by exposure to high
temperatures. Recommended storage is at about 50-60 degrees Fahrenheit, at
a 40% state of charge. Other than proper storage, they do not require any
conditioning whatsoever. An advantage of LiIon batteries is their low rate
of self-discharge - less than half that of nickel-based batteries.
Additionally, lithium-ion battery chemistry is under constant development and
advanced formulas, which feature higher output and improved aging
characteristics are emerging every day.
Battery Charging Technology
Charging Methods
There have been significant advances in battery charging technology in
recent years. Lithium-ion batteries, while very sensitive to charging
conditions are actually considered to be simpler to charge than NiCd and NiMH
batteries. This is due to the fact that lithium-ion battery assemblies
contain a sophisticated electronic circuit, which precisely controls the
charging parameters and provides safety measures.
The most common and reliable method for charging cadmium-based batteries (NiCd and NiMH) is the "Negative Delta V" method. This method senses a fully charged battery by detecting a drop in cell voltage as the battery reaches capacity. This drop is small but noticeable enough to be detected and signal the charger to shut off or to trickle depending on the charger type. Other chargers use "Delta T" or change in temperature sensors to decide when to stop charging. "Delta T" chargers are less reliable and many manufacturers have adopted the "Delta V" or a combination of the two as their preferred method of choice.
Analyzers & Conditioners
A battery analyzer is used to determine the battery's ability to store a
charge. By using it, you will be able to tell if a battery is delivering
the correct voltage and amperage. An incorrect voltage reading is usually
caused by a dead or shorted cell. In this case, the battery should be
discarded, rebuilt or returned, if under warranty. A conditioner is
a sophisticated device that will perform a series of charge and discharge cycles
on a battery. This is usually done to "break through" the memory
barrier that may occur on a Nickel-Cadmium battery or to restore a battery that
has remained discharged for a long time.