Apple Macintosh PowerBook 145B - Manual (Page 123)

Maximizing battery life
To maximize battery life, discharge and then recharge the battery
completely once every 90 days. Just use the computer as you
normally would, but ignore the low-power messages that appear
on the screen. (Make sure to save your work, however.) When the
computer goes to sleep automatically, recharge the battery
completely before using that battery again. You can do this in
either of two ways:
m Leave the battery in the computer, plug in the power adapter,
and let the battery recharge overnight, or
m Remove the battery from the computer and recharge it in a
recharger for 5 hours (if you are recharging just one battery)
or 10 hours (if you are recharging two).
Your battery will last longer if you recharge it at or slightly below
room temperature.
With proper care you can expect your battery to last for at least
a year. If you notice that the battery no longer holds a charge for
as long as it should, you may need to replace it.
108 Chapter 7: Power Management