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Home » Battery Basics
- 1. What is a battery?
- Battery can be any device that stores energy for later use. The word battery is limited to an electrochemical device that converts chemical energy into electricity, by use of a galvanic cell. A galvanic cell is a fairly simple device consisting of two electrodes (an anode and a cathode) and an electrolyte solution. Batteries consist of one or more galvanic cells.
A battery is an electrical storage device. Batteries do not make electricity, they store it. As chemicals in the battery change, electrical energy is stored or released. In rechargeable batteries this process can be repeated many times.
- 2. What is a battery pack?
- When battery cells are assorted and configured in a predefined order, they are referred to as a battery back, which delivers a desired voltage, capacity, or power density.
- 3. What is Volt?
- A volt is a measure of electrical pressure or force. Referred to as "V" for voltage, different volts or voltages will be found in batteries of different chemistries. For instance, Ni-Cd and Ni-MH batteries are nickel based, providing a cell voltage of approximately 1.2V, while a Li-ion cell provides 3.6V/3.7V.
With that said, the voltage of two battery cells of the same chemistry is always the same. While their capacities may differ, the voltage always remains the same. Likewise, it is crucial that the voltage of a cell or a battery pack always mirrors that of the voltage requirement of the device in which it is used. If there is a difference between the two, the device will malfunction and enough malfunctions may also cause permanent damage.
- 4. What is battery capacity?
- Battery capacity can be described as the electrical energy content, which is usually expressed in milliAmpere-Hours (mAh). This is determined by the amount of electrical energy the battery has capacity to deliver – under stated conditions of temperature, rate of discharge and final battery voltage, all over a specific time period. As one might guess, the higher the battery capacity rating, the higher the mAh, and the longer the battery will last. Thus, for laptop computers and other portable devices that are used for long periods of time, batteries with higher capacities are preferred.
- 5. What is Amperage?
- The measure of electrical current flow is referred to as an ampere or Amp. It describes the rate of flow of electricity through a specific point during one second of time.
- 6. What is milliampere-Hour (mAh)?
- When you want to measure capacity of a battery, you’d want to measure by mAh. This capacity figure can be calculated by multiplying the electrical current in miliamperes (mA) by the length of time that the current is flowing. As one can deduct, the higher the "mAh", the higher battery capacity, resulting in longer battery life between charges.
- 7. Are Li-ion batteries affected by "Memory Effect"?
- Quite simply, no – Lithium ion batteries are not affected by "Memory Effect". Such an action would result in a drop in the capacity or voltage of a rechargeable battery. While Li-ion batteries are not impacted by "Memory Effect", it does impact NiCd and NiMH because they are nickel-based. Thus, laptop users can become quite rustrated with unexpected downtimes.
- 8. What is cycle life of a battery?
- When you calculate the number of times a battery can be charged and discharged before it fails, you are measuring battery life cycle. Thus, one battery cycle is defined as a full charge that is followed by a full discharge.
- 9. What is self-discharge?
- When a battery loses its charge when it’s not in use, it’s referred to as a self-discharge. If a battery sits without being used, it will lose its charge, and this self-discharge is at its highest following a full charge of a battery at full capacity. There are other factors that impact the rate of self-discharge, including temperature of where the battery is stored and even the humidity present. And this is true regardless of battery type or chemistry. Li-ion batteries have the lowest self-discharge rate – 5% to 10% per month; quite low compared to 20% of the Ni-Cd, 30% of the Ni-Mh.
- 10. What charging precautions should be taken when charging Li-ion batteries?
- Contacts: For optimal charges, one must ensure that both the charger and the battery contacts are clean. The result of dirty contacts? One can expect charger and/or battery malfunction in such a situation.
Temperature: Ideal room temperatures range between 0°C and 45°C for Lithium-ion batteries.
Charging voltage: If the voltage surpasses 4.2 volts per cell, Li-ion batteries have an inbuilt protection circuit that automatically cuts off the current path. To improve battery life cycle, one should be cautious of charging their Li-ion batteries to this 4.2 volt limit.
- 11. What precautious should be taken when storing laptop batteries?
- Heat and metal objects do not act well with laptop batteries. Best practices include removing laptop batteries and storing them in a dry and cool storage space. When stored, batteries should be discharged to 40%. Prolonged storage of Li-ion batteries for more than three months is not recommended.
- 12. What is battery life?
- Battery life, as one might suspect, is a measure of the number of battery cycles a battery can provide before it "dies" and needs to be completely replaced. Battery life varies between chemistries, but Li-Ion batteries generally provide around 300 charge/discharge cycles.
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