Sharp PC-9080 Manual page 50

If you have not used the notebook for a long time, the battery may
become completely discharged. In such a case, recharging will take
more time than usual.
If you use the notebook for a while, the battery will become hot. The
notebook starts recharging after getting back to the normal
temperature.
Maintaining the Battery Pack
You should discharge the battery pack if you do not use the notebook for a long time
and should recharge it fully before use. If the battery is fully charged and left unused
for a long time.
The battery will discharge itself slowly, and
The life of the battery will be shortened.
Lithium-ion batteries do not have so-called "memory effect,"and you do
not have to deep discharge the battery pack before charging it.
Disposing of Battery Packs
The capacity of a battery pack is gradually decreasing while used repeatedly.
Although the deterioration rate depends on the operating temperature and
environments, the pack can sufficiently be used for 500 times, after which you
should consider purchasing a replacement battery pack that is identical to the battery
pack.
Your local area may have rules which you should follow regarding battery disposal.
In addition to the main lithium-ion battery, you should remember the small backup
battery located under the keyboard. Bring your notebook to a local dealer for
replacement of this backup battery if your notebook begins to lose its time and date
setting.
Backup batteries
The notebook has two backup batteries. The rechargeable NiMH battery prevents
loss of data during replacement of the lithium-ion battery while in the suspend mode.
However, this will not work if the battery level of the NiMH battery is low.
Therefore, power-off or suspend to disk is recommended when replacing the lithium-
ion battery.
The other backup battery is a non-rechargeable coin type Lithium battery for RTC.
Using Your Notebook 3-5
3