- What is a battery?
A battery is a device that generates an electrical current by chemical reaction.
- How does a battery work?
Batteries operate on a simple theory: two dissimilar metals (electrodes) in contact with an electrolyte will produce a flow of electrons (electricity) when all elements are in contact with each other.
- What is a battery pack?
A battery pack is an assortment of battery cells, configured in a predefined order - a series, parallel or a mixture of both - to deliver the desired voltage, capacity, or power density.
- What are the different categories of batteries?
Batteries fall into two general categories -- primary batteries and secondary batteries.
Primary batteries cannot be recharged or "brought back to life" once they have used up their power. Examples of primary batteries include alkaline batteries that are commonly used in flashlights, portable radios and other consumer electronics devices.
Secondary batteries, also known as storage batteries, are capable of being recharged by the application of electrical energy. Nickel Cadmium batteries, Nickel-Metal Hydride batteries and Li-Ion batteries (used in many portable electronic devices such as two-way radios, barcode scanners & barcode printers) are examples of rechargeable batteries.
- What are the different rechargeable battery chemistries?
Nickel Cadmium (NiCd), Nickel Metal Hydride (NiMH) or Lithium Ion (Li-Ion) technologies are the three most common rechargeable battery chemistries. Their general characteristics and primary uses are noted below:
- Nickel Cadmium (Ni-Cd)
Nickel Cadmium is one of the most rugged rechargeable battery chemistries. They are very suitable for use in small, portable devices such as two-way radios and power tools. Ni-Cd batteries perform well in rigorous conditions such as low temperatures, can be re-charged immediately even after long periods of storage, and are economically priced. However, if a battery is not maintained properly (i.e. not fully discharged after each use) it develops a condition known as "memory effect."
- Nickel Metal Hydride (Ni-MH)
Nickel Metal Hydride is a rechargeable battery chemistry that can be used to replace Ni-Cd chemistry in certain applications. Ni-MH shows significant improvements over Ni-Cd rechargeable batteries in terms of performance (significantly reduced “memory effect” when compared with Ni-Cd), increased energy density, environmental friendliness, and lighter weight.
- Lithium Ion (Li-Ion)
Among the three basic battery chemistries, this is the most advanced .The Lithium Ion (Li-Ion) battery is a very high energy density rechargeable chemistry, has low self- discharge, and no memory effect .This chemistry is ideal when smaller and lighter weight batteries are required, such as cell phones and laptop computers.
- Nickel Cadmium (Ni-Cd)
- What is Volt?
Volt (V) is a unit of electrical force or electric pressure. It can be explained as the electrical “Pressure” in a circuit.
- What is Amperage?
Ampere (Amp) is a measure of electrical current flow. In other words, Amp = the “Quantity” of electron flowing through a specific point in one second.
- What is milliampere-Hour (mAH)?
It is a measure of a battery’s capacity, i.e. the amount of power that is packed into the battery. Higher ‘mAH’ rating results in longer battery life between charges.
- What is “Memory Effect”?
“Memory effect” is the drop in capacity or voltage in a rechargeable battery. Batteries develop a memory when they are charged without first being completely discharged or when continuously charged for a prolonged period. This process causes a battery to hold less charge over time. Suppose, a partially charged battery is repeatedly re-charged without being fully discharged, it will gradually develop a “memory” of the level from where it was “topped up” and stop to charge to its full capacity. Ni-CD batteries tend to suffer from memory effect more than the Ni-MH batteries.
- What is cycle life?
Cycle life is the number of times a battery can be charged and discharged before it runs out of its energy. One cycle is defined as a full charge followed by a full discharge.
- What is self-discharge?
Self-discharge is the loss of charge in a battery when not in use. Unused batteries lose their charge over time. The loss of charge, or self-discharge, is the highest right after charge when the battery holds full capacity. Other factors like humidity and temperature of the storage place also contributes to the rate of self-discharge.
- What charging precautions should be taken when charging a battery pack?
Clean contacts: To achieve optimum charge contact, be sure both charger and battery contacts are clean. Dirty contacts can result in a charger/battery malfunction.
Optimum charging temperature: Ni-CD batteries are designed to be operated and charged at 65°F. Charging batteries in high temperatures causes the battery to reach a point where the battery discharges, due to faster chemical reactions caused by higher temperatures. Thus, a battery never reaches full charge giving "memory effect." Conversely, chemical reactions slow down in cold ambient temperatures. At cold temperatures, the cells may not be able to accept the charge current. This builds pressure and creates the potential for cell rupture. As a rule, never charge a battery when the ambient temperature is warmer than 120°F or colder than 40°F.
- What steps should be followed for the initial charge cycle to maximize battery performance?
All batteries are shipped uncharged. Initially, all new batteries must be charged for 14 - 16 hours continuously. All batteries require a "break-in" period, so don't be alarmed if your battery doesn't hold a full charge right away. A new battery may show false full charge as indicated on your charger. Also the battery may not power up the device because of low voltage.
It is recommended that for the first 5 to 10 cycles one must charge the battery fully and drain it fully before recharging. This will properly condition the battery and will ensure that it will operate at its maximum capacity. This is recommended for all batteries. You can discharge most batteries by unplugging the charger and leaving the battery in the device (e.g. two-way radio) and leaving the device turned on until completely discharged.
- What precautious should be taken when storing battery packs?
It is very important that batteries be stored in cool dry places away from heat and metal objects.
- How should batteries be charged after they have been in storage (or un-used) for over three months?
It is recommended to use a slow trickle charge for batteries that have been stored for more than 3 months. After the first slow charge, a rapid charge may be used.
It is also recommended that batteries be periodically analyzed and reconditioned to optimize battery life and capacity.
- What is battery maintenance?
Battery maintenance is the periodic exercising and reconditioning of batteries to optimize their charge carrying capacity. Batteries lose their charge carrying capacity or develop “memory effect” when continuously charged even after the batteries have been fully charged or when charged without first being completely discharged. Proper battery maintenance can optimize battery life and restore the capacity by as much as 50% to 70%.
- What is battery conditioning?
Nickel-based batteries don’t perform to their full capacity when new. In order to reach their full potential, they need to be cycled, i.e. fully discharged and fully recharged, a few times. This is called battery conditioning.
- What is battery life?
It is the number of battery cycles, a full charge followed by a full discharge, a battery can offer before it needs to be replaced. NiCd batteries generally offer the maximum number of charge/discharge cycles followed by NiMH batteries. Under proper maintenance, a NiCd battery can offer over 1000 cycles and a NiMH battery can offer from 300-500 battery cycles. Li-Ion batteries generally offer the lowest battery life at 300 cycles.