Battery life expanding guide
|Battery Type||Lithium ion|
|General||* avoid deep discharges except when resetting fuel gauge or reconditioning a battery; partial dis-/recharges are better for the battery lifetime (note: fuel gauge will slowly get inaccurate over time)|
|* remove battery when on AC (due to heat)|
|* avoid exposing the battery (or notebook) to excessive heat|
|Charging||* avoid charging if battery is nearly full, unless you will need its full capacity soon; keep it on the 30%-85% charged range|
|* keep notebook off while charging due to heat|
|* fully discharge, then fully charge battery when needed to recalibrate fuel gauge; newer battery pack models require this less often, old ones might need it as often as every 30 cycles|
|Storage||* never fully charged or discharged, ideally at about 40%|
|* cool and dry, but do not freeze them: 10-15C is recommended|
Batteries, especially of the modern Li-Ion type, wear out quicker when they hold a large charge or are subject to higher temperatures (see above).
If you use your laptop at a desk, reduce battery wear by maintaining an appropriate charge level. When possible, remove Li-ion batteries while operating from AC as the notebook gets hot enough inside for that to damage the battery in the long run, even if charging is stopped.
On recent ThinkPads, charging thresholds can be configured in the bundled software. Under Linux, this is supported on recent models by the tp_smapi driver (and even without tp_smapi, if you have a dual-boot setup, you can set the thresholds under Windows and they will be remembered as long as you don’t power off your machine with AC disconnected; suspend to RAM is OK). Have a look at How to use UltraBay batteries.
If you have spare Li-ion battery packs, store them at 40% charge in a cool place (15C being a recommended temperature, do not let the batteries freeze). If storing inside a refrigerator, beware of humidity, and be careful with cold spots that can easily freeze the battery if anything goes wrong.