Primaries: Difference between revisions
→Lithium
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Lithium batteries have a very long shelf life. After 10 years, they might retain 80% of their original charge. They are a good choice for an emergency flashlight or one that is not used that often. They also weigh noticeably less than other batteries. | Lithium batteries have a very long shelf life. After 10 years, they might retain 80% of their original charge. They are a good choice for an emergency flashlight or one that is not used that often. They also weigh noticeably less than other batteries. | ||
Energizer - 1.7V/cell. The higher voltage makes some flashlights brighter than on alkalines or NiMHs. Energizer retains a patent on lithium AA and AAA batteries in the US and therefore are the only company to offer this chemistry there. These batteries are widely available and come in two varieties: "advanced" and "ultimate". The "ultimate" has blue on the label and is the same thing as the earlier e2 lithiums (both versions have the same part number: L91 for AA and L92 for AA batteries). These are advertised as lasting 8 times as long as alkaline batteries (realistically it might be 4 times as long, but they cost 3 times as much). The "advanced" lithiums have yellow on the packaging (the part numbers are EA91 for AA and EA92 for AAA cells) and are advertised to last 4 times as long as alkalines, but in practice they have about 75% of the capacity of Ultimates (so maybe 3 times as long as alkalines). They are usually less expensive than the Ultimate Lithiums. | Energizer - 1.7V/cell. The higher voltage makes some flashlights brighter than on alkalines or NiMHs, briefly. Energizer retains a patent on lithium AA and AAA batteries in the US and therefore are the only company to offer this chemistry there. These batteries are widely available and come in two varieties: "advanced" and "ultimate". The "ultimate" has blue on the label and is the same thing as the earlier e2 lithiums (both versions have the same part number: L91 for AA and L92 for AA batteries). These are advertised as lasting 8 times as long as alkaline batteries (realistically it might be 4 times as long, but they cost 3 times as much). The "advanced" lithiums have yellow on the packaging (the part numbers are EA91 for AA and EA92 for AAA cells) and are advertised to last 4 times as long as alkalines, but in practice they have about 75% of the capacity of Ultimates (so maybe 3 times as long as alkalines). They are usually less expensive than the Ultimate Lithiums. While they have an initial voltage in excess of 1.7V, this bleeds off very quickly and the temporary increase in brightness compared to alkaline cells is short. Their real advantage is very long shelf-life and low-temperature tolerance, they will still produce useful current at lower temperatures than just about all other cell chemistries. Otherwise they are extremely expensive for the capacity they offer. | ||
CR123A and others specialty cells are also lithium and usually 3 volts per cell. There was a time when some made in China CR123A cells were causing problems for people on CPF and therefore some will only recommend buying Made in USA cells which never displayed those problems. | CR123A and others specialty cells are also lithium and usually 3 volts per cell. There was a time when some made in China CR123A cells were causing problems for people on CPF and therefore some will only recommend buying Made in USA cells which never displayed those problems. | ||
Saft - This company has a line of lithium primaries that are 3.6 volts per cell. | Saft - This company has a line of lithium primaries (LiSOCl2 - Lithium-thionyl chloride chemistry) that are 3.6 volts per cell. | ||
==Button Cells== | ==Button Cells== | ||
Some very small lights and keychain lights use button cells. These come in a wide variety of sizes and chemistries which are explained in greater length in the [http://en.wikipedia.org/wiki/Button_cell Wikipedia article]. | Some very small lights and keychain lights use button cells. These come in a wide variety of sizes and chemistries which are explained in greater length in the [http://en.wikipedia.org/wiki/Button_cell Wikipedia article]. | ||