Panasonic FX-55 Series Operating Instructions Manual page 39

Remove peripheral devices (USB devices, external mouse, etc.) when not in use
When the network communication is not working, turn off the wireless LAN
When the computer is not going to be used for an extended period (a month or more)
In order to maintain the battery performance, remove the battery with a remaining charge of 30 % to 40 % from the computer,
and store it in a cool, dark place
If the battery pack is kept installed in the computer, it will discharge gradually even when the computer's power is off. If this condition continues for a long
period (several months or more), the battery may overdischarge, causing its performance to deteriorate. In addition, this deterioration will accelerate if
the battery pack is stored inside a vehicle with all its windows closed and exposed to the hot sun or in other places where the temperature is high. Store the
battery pack where the temperature is within the range of 10 °C to 30 °C {50 °F to 86 °F}.
Things to keep in mind when using the battery pack
Bear in mind the following points when installing and removing the battery pack
Do not install or remove the battery pack while the computer is in the sleep mode.
Removal of the battery pack in this mode cause the data to be erased and cause the computer to malfunction.
Do not touch the terminals on the battery pack.
If the terminals are dirty or damaged, the battery may not function properly or the computer may not operate properly.
Charging time and discharging time differs depending on the computer's power status and temperature
It takes longer to fully charge the battery when the computer's power is on. To charge the battery more quickly, power the computer off,
or put it in the sleep or the hibernation mode.
It takes longer to fully charge the battery in low temperature environments. The battery discharges more quickly in low temperature
environments.