The Macintosh Portable uses a sealed, lead-acid (SLA) battery. SLA cells
have a constant voltage drop as they lose their charge. This enables the
Macintosh Portable to alert the user when power is running low.
The cycle life of an SLA battery varies depending on the depth of
discharge. If the battery is discharged to 100% of the energy in the
battery, the battery can get 200 charge/discharge cycles before it has to
be replaced. If discharged to 25% depth, the battery can get 2,000
charge/discharge cycles. The recharging system used in the Macintosh
Portable keeps the battery at full charge to extend the number of
charge/discharge cycles.
The external battery recharger charges a spare battery when the user is
still using the Macintosh Portable. It uses the same power adapter as
the Macintosh Portable, and has the same power input requirements as the
Macintosh Portable power adapter (120/240 VAC 50/60Hz). It includes a
recharge cradle to hold the battery. The battery charger LED, located on
the top of the unit, will display:
LED Color Status
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Amber (Yellow) Charging
Green Fully Charged
No Light Replace Battery