Follow the notice below, Better using your Sony BPS40 Laptop Battery
Storage - Store your BPS40 Laptop Battery in a clean, dry,
cool place away from heat and metal objects. The Sony BPS40 batteries will self-discharge during storage; remember stored at about 40% state-of-charge.
Charge and discharge - For lithium ion batteries, you do not need to discharge them fully and recharge constantly. You need to do a full discharge only about every 30 charges. Do not charged to higher voltages than its threshold voltage
Exercise Your BPS40 Battery - Do not leave your batteries dormant for long periods of time. We recommend using the battery at least once every two to three weeks. If a battery has not been used for a long period of time, perform the new battery break in procedure described above.
Calibrate Your batteries - If your Battery's 76% even less in work , you must fully charge, fully discharge, and then fully recharge the Laptop Battery pack. Consider removing the BPS40 battery from a laptop when running on fixed power
Do not short-circuit. A short-circuit may cause severe damage to the battery.
Avoid propping your laptop on a pillow, blanket, or other soft surface that can heat up. Your BPS40 battery is a lot less efficient when not within its standard operating temperature range.
If the capacity is low in current,CPU will be in electricity-saving model and battery can not be charged.In this case,take off the battery and fit on to rouse the CPU. The BPS40 battery can be charged then.
Remove the battery when don't use if for long time,or the currency will be lost and the cell will be damaged.
Recharge the battery as the circle more than once per month to make the management of capacity reach its best status, and prolong Sony BPS40 Laptop Battery useful life.