I have a 5 year old Apple MacBook (the first Intel processor based model) whose battery can maintain a charge that is about 75% of what it was when it was brand new. This is very good for such an old battery. On the other hand I have an Asus T1000HA netbook whose battery could not keep a charge less than a year after I bought it. There’s a Windows warning message on it that I should replace the battery.
If you have ever wondered why Lithium-ion batteries in your various gadgets ages the way they do, you may want to take a look at this article over on BatteryUniversity.com:
It presents detailed test and technical information about Lithium-ion batteries. Here are some of the advice and recommendations Battery U. provides:
– Avoid frequent full discharges and charge more often between uses
– There is no memory and the battery does not need periodic full discharge cycles other than to calibrate the fuel gauge on a smart battery
– Exposing the battery to high temperature and being at full state-of-charge for an extended time can be more damaging than cycling
– The worst condition is keeping a fully charged battery at elevated temperatures, which is the case when running a laptop on the power grid
– Placing a cellular phone on the heat generating (wireless) charging mat stresses the battery more than if charged on a designated charger
– When not in use, store the battery in a cool place. For long-term storage, manufacturers recommend a 40 percent charge. This allows for some self-discharge while still retaining sufficient charge to keep the protection circuit active.
– Heat buildup is always a concern and running a laptop in bed or on a pillow may contribute to this by restricting airflow. Not only will heat stress electronic components, elevated temperature causes the electrodes in the battery to react with the electrolyte and this will permanently lower the capacity. Placing a ruler or other object under the laptop to increase floor clearance improves air circulation around the enclosure and keeps the unit cooler.
– Should I disconnect my laptop from the power grid when not in use? Under normal circumstances this should not be necessary because once the lithium-ion battery is full, a correctly functioning charger will discontinue the charge and will only engage when the battery voltage drops to a low level.
– A Li-ion battery can also fail because of undercharge. This occurs if a Li-ion pack is stored in a discharged condition. Self-discharge gradually lowers the voltage of the already discharged battery and the protection circuit cuts off between 2.20 and 2.90V/cell.