Batteries are ready to work in an instant (providing they are charged) and can be used over a wide temperature range. Charging, on the other hand, has limitations and the user should follow recommended guidelines on how and when to charge. Each battery chemistry has its own preferred charging method. Each type also has unique needs that must be met to obtain reliable service and long life.
Batteries behave like humans; some live to a great old age, others die early. Exposure to heat is the biggest enemy. Steps can be taken to prolong battery life but in the real world optimal handling may not always be practical. Deviations from the ideal are acceptable but will lower the life expectancy of the battery to some degree. This article summarises these needs and advises proper the handling of each battery type from purchase to 'bin'.
(The abbreviation NiCad is a registered trademark of SAFT Corporation and should not be used to refer generically to nickel-cadmium batteries, although this brand-name is commonly used to describe all nickel-cadmium batteries).
Voltage: 1.2V per cell. ('PP3' types are generally 7.2V although Varta made 8.4V batteries for more critical applications).
Capacity: Varies - dependent on size and construction technology.
Cycle durability: 2000 cycles
The nickel-cadmium battery (commonly abbreviated NiCd and pronounced "nye-cad") is a popular type of rechargeable battery using the nickel hydroxide (NiOH) and metallic cadmium (Cd) as the active chemicals.
Sealed NiCd cells may be used individually, or assembled into battery packs containing two or more cells. NiCd dry cells are manufactured in the same sizes as primary cells - AAA, AA, C & D, are often used for portable radios. When NiCds are substituted for primary cells, the lower terminal voltage and smaller amphour capacity may reduce performance over primary cells, if making your own 'pack' the voltage issue can be overcome by using 5 cells per 6V instead of the 4 cells per 6V of primaries, where space allows. NiCd is one of the most hardy and durable chemistries.
NiCd batteries have a very low internal resistance and, if the terminals are shorted, can 'dump' their whole charge very quickly with rapid and dangerous heat buildup and may even cause a fire or explosion. This low internal resistance gives them the edge in very high current drain applications such as cordless power tools and RC cars.
A major disadvantage (or advantage, depending on your views) is that a NiCd will deliver full voltage throughout its charge cycle but gives little warning of dscharge. This gives full output until the battery is 'dead', not very good for two way communications but cost made them a popular choice over primary (disposable) cells.
Prime a new battery by putting on a 14-16 hour charge. Without priming the performance will be low at first, then gradually improve with use.
Rechargeable batteries can be used under a wide temperature range. This does not automatically permit charging at these extreme conditions.
The maximum allowable charge temperatures for NiCd are:
Slow charge: 0° - 45°C (32° - 113°F)
Fast charge: 5° - 45°C (41° - 113°F)
Charging a hot battery decreases the charge time and the battery may not fully charge.
Do run the battery fully down once per month. Try to use up all energy before charging.
Do not leave battery in charger for more than 2 days, a prolonged trickle charge to a fully charged battery can be harmful.
Avoid getting battery too hot during charging.
Always allow to fully charge without interruptions. Repeated partial charge can cause heat buildup. (Many chargers terminate charge by heat. A fully charged battery will re-heat, causing overcharge.)
The nickel metal hydride battery, abbreviated NiMH, pronounced 'Nimm', is a type of rechargeable battery similar to a nickel-cadmium (NiCd) battery but it has a hydrogen-absorbing alloy for the anode instead of cadmium.
Like the NiCd batteries, nickel is the cathode. The 'metal' in the anode of a NiMH battery is actually an intermetallic compound. Many different compounds have been developed for this application, but those in current use fall into two classes. The most common is AB5, where A is a rare earth mixture of lanthanum, cerium, neodymium, praseodymium and B is nickel, cobalt, manganese, and/or aluminum. Very few batteries use a higher-capacity negative material electrode based on AB2 compounds, where A is titanium and/or vanadium and B is zirconium or nickel, modified with chromium, cobalt, iron, and/or manganese, due to the reduced life performances.
A NiMH battery can have two to three times the capacity of an equivalent size NiCd and the memory effect is not as significant. NiMH batteries do not have as low an internal resistance as NiCd. NiMH cells are manufactured in the same sizes as primary cells - AAA, AA, C & D, are often used for handheld radio transceivers.
When NiMHs are substituted for primary cells, the lower terminal voltage may reduce performance over primary cells, if making your own 'pack' the voltage issue can be overcome by using 5 cells per 6V instead of the 4 cells per 6V of primaries, where space allows. NiMH has higher energy density than NiCd at the expense of shorter cycle life.
Lithium-ion batteries (sometimes abbreviated Li-ion batteries) were first proposed in the 1960s. The first commercial lithium ion battery was released by Sony in 1991.
They are commonly used in consumer electronics (mobile phones, personal MP3 players, laptop computers and some handheld radio transceivers). They are currently one of the most popular types of battery for portable electronics because they can be formed into a wide variety of shapes and sizes so as to efficiently fill available space in the devices they power. They have one of the best energy-to-weight ratios, no memory effect and a slow loss of charge when not in use which makes them a popular choice. They can be dangerous if mistreated and unless care is taken their lifespan may be reduced.
Lithium-ion batteries lose 5 to 10% of their storage capacity every year from the time of manufacture whether the battery is used or not!
Li-ion batteries are lighter than other equivalent secondary batteries, often much lighter. The energy is stored in these batteries through the movement of lithium ions. Lithium is the third lightest element, giving a substantial saving in weight compared to batteries using much heavier metals. However, the bulk of the electrodes are effectively "housing" for the ions and add weight, and in addition "dead weight" from the electrolyte, current collectors, casing, electronics and conductivity additives reduce the charge per unit mass to little more than that of other rechargeable batteries. The forte of the Li-ion chemistry is the high open circuit voltage in comparison to aqueous batteries (such as nickel cadmium, nickel metal hydride and lead acid).
Lead-acid is the oldest rechargeable battery in existence. During the mid 1970s, researchers developed a maintenance-free lead-acid battery that could operate in any position. The liquid electrolyte was transformed into moistened separators and the enclosure was 'sealed', actually vented in case of gassing. It has retained a market share in applications where newer battery chemistries would either be too expensive or the upkeep would be too demanding. There are simply no cost-effective alternatives for such applications as cars and motorcycles (flooded) wheelchairs, scooters, golf carts and UPS systems ('sealed').
Driven by different market needs, two 'sealed' lead-acid systems emerged: the small sealed lead-acid (SLA), also known under the brand name of Gelcell, and the valve-regulated-lead-acid (VRLA). Technically, both batteries are the same. (Engineers may argue that the word 'sealed lead acid' is a misnomer because no rechargeable battery can be totally sealed).
Unlike the flooded lead acid battery, both SLA and VRLA are designed with a low over-voltage potential to prohibit the battery from reaching its gas-generating potential during charge. Excess charging would cause gassing and water depletion. The electrolyte in a 'sealed' type, obviously, cannot be topped up as a flooded battery can. Consequently, these batteries can never be charged to their full potential.