User`s guide

Chapter 2: Power and Your Computer
2–2 Digital HiNote VP 500 Series
General Battery Information
All batteries have limited life span. A battery’s life span is measured by the number of
charging and draining cycles it can undergo before it can no longer be charged. The amount of
time that your system can be operated by battery power before the battery is drained is referred
to as battery run time.
Nickel Metal Hydride Battery Care
Your notebook’s main battery is an Enhanced Nickel-Metal Hydride. Nickel-Metal Hydride
(NiMH) batteries are extremely common in many types of portable systems, such as cellular
phones and portable computing devices.
Memory Effect
A NiMH battery in poor condition may begin to exhibit characteristics of “memory effect.” A
memory effect will occur when a user does not allow the battery to fully drain before charging it
again. For example, if you use the battery for 20 minutes at a time and then recharge it, the
battery will tend to “remember” that it only needs to operate 20 minutes per charge. As a
result, during the charging process, the declining battery will only receive a portion of its
charge capacity.
NiMH Battery Life
The memory effect has a direct impact on the battery’s life span. NiMH batteries have a typical
life (charge/drain cycles) of up to 800 cycles. If the battery is used an average of 30 minutes
per cycle, you can expect a total life of 400 hours. If you use the battery 3 hours per cycle, you
can expect a total life of 2,400 hours. Therefore, it is advantageous to use the battery as much
as possible during each cycle.
However, in attempts to prevent the memory effect, it may not always be practical to
continuously use your notebook until the battery drains to its minimum level. As a solution,
Digital recommends that users periodically “form” or condition the battery. When a battery is
formed, it is put through a series of charging and draining cycles. A battery which is formed
will perform better and last longer than a battery which has not been formed.