When using a laptop as a desktop replacement the thinkpad t400 battery should not be left in for long periods of time. The laptop will over time discharge the battery. Remove the battery – making sure that it is charged to 40% and store it in a dry, warm place. Ensure that it is wrapped protectively and nothing will be dropped on it.
The battery should be re-installed every 3-4 weeks and allowed to fully discharge. Leaving a thinkpad x200 battery in storage for longer than this without using could cause the battery to fully discharge as the circuitry of the battery itself consumes power.
Leaving a thinkpad x200 battery in a laptop while using an electrical outlet for long periods of time will keep the battery in a constant state of charging up and that will reduce the life cycle of the battery.
Remember that when you have removed the battery from a laptop while using with an electrical outlet – the automatic battery backup is no longer functional. Make sure to plug your laptop into an uninterrupted power source (UPS) not directly into an outlet or surge protector.
How long should a rechargeable battery last?
The life of a rechargeable thinkpad t400 battery operating under normal conditions should be between 500 to 800 charge-discharge cycles. This translates into one and a half to three years of battery life for the average user. As your rechargeable battery begins to die, you will notice a decline in the running time of the battery. When your two hour battery is only supplying you with twenty minutes worth of use, it is time for a new one. When a thinkpad x200 battery is not used for extensive periods of time it should be removed from the device and stored in a cool, dry and clean environment. Self-discharge will occur when the battery is not used for an extended time period. Fully charge the battery before use after storage. Long term storage will have permanent effects on the battery’s capacity.