Guidelines for prolonging Li-ion battery life
* Unlike Ni-Cd batteries, lithium-ion batteries should be charged early and often. However, if they are not used for a longer time, they should be brought to a charge level of around 40%. Lithium-ion batteries should never be "deep-cycled" like Ni-Cd batteries.
* Li-ion batteries should be kept cool. Ideally they are stored in a refrigerator. Aging will take its toll much faster at high temperatures. The high temperatures found in cars cause lithium-ion batteries to degrade rapidly.
* Lithium-ion batteries should never be depleted to empty (0%).
* According to one book, lithium ion batteries should not be frozen (should not be stored under -40 °C), because most lithium-ion battery electrolytes freeze at approximately −40 °C, which is much colder than the lowest temperature reached by most household freezers.
* Li-ion batteries should be bought only when needed, because the aging process begins as soon as the battery is manufactured.
* When using a notebook computer running from fixed line power over extended periods, the battery can be removed and stored in a cool place so that it is not affected by the heat produced by the computer. However, a notebook computer's battery prevents sudden loss of the data in memory during power failures and voltage drops. Reasonable alternatives are the use of an older lithium ion battery or an external uninterruptible power supply.
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