Guidelines for prolonging lithium-ion battery life

• Lithium-ion batteries should never be depleted below their minimum voltage (2.4 to 2.8 V/cell, depending on chemistry). If a lithium-ion battery is stored with too low a charge, there is a risk that the charge will drop below the low-voltage threshold, resulting in an unrecoverable dead battery.[citation needed] Usually this does not instantly damage the battery itself but a charger or device which uses that battery will refuse to charge a dead battery. The battery appears to be dead or not existent because the protection circuit disables further discharging and there is zero voltage on the battery terminals.

• Lithium-ion batteries should be kept cool. Ideally they are stored in a refrigerator.[citation needed]
• Aging will take its toll much faster at high temperatures.[38]

Simple Guidelines

Avoid frequent full discharges because this puts additional strain on the battery. Several partial discharges with frequent recharges are better for lithium-ion than one deep one. Recharging a partially charged lithium-ion does not cause harm because there is no memory. (In this respect, lithium-ion differs from nickel-based batteries.) Short battery life in a laptop is mainly cause by heat rather than charge / discharge patterns.

A charge cycle means using all of the battery’s power, but that doesn’t necessarily mean a single charge. For instance, you could listen to your iPod for a few hours one day, using half its power, and then recharge it fully. If you did the same thing the next day, it would count as one charge cycle, not two, so you may take several days to complete a cycle. Each time you complete a charge cycle, it diminishes battery capacity slightly, but you can put notebook, iPod, and iPhone batteries through many charge cycles before they will only hold 80% of original battery capacity. As with other rechargeable batteries, you may eventually need to replace your battery.