HP Compaq Compaq 370698-001 Reference Manual page 45

In addition, follow these suggestions to extend the life of your
battery packs:
Do not leave battery packs unused for long periods. If you
have more than one, rotate them.
Unplug the AC adapter when the notebook is not in use.
If the notebook will be unused and unplugged for more than
2 weeks, remove and store the battery pack.
CAUTION: To prevent damage to the battery pack, do not expose it to
Ä
high temperatures for extended periods of time.
High temperatures accelerate the self-discharge rate of a
stored battery pack. To prolong the charge of a stored battery
pack, place it in a cool, dry location.
To maintain the accuracy of battery charge displays, calibrate
a battery pack that has been stored for one month or more
before using it.
Avoid using or charging battery packs at high temperatures.
Reference Guide
Battery Packs and Power Management
3–7