Advantages
Compared to the Nickel Cadmium (NiCad) batteries used in other PowerBook models, the nickel-metal hydride (NiMh) rechargeable batteries in the PowerBook Duo:
* Are smaller and lighter.
* Have a 20% greater power capacity for the same size and voltage.
* Are considered environmentally safer because they lack cadmium.
A fully-charged PowerBook Duo battery will operate approximately 2 to 4.5 hours, depending on the operating temperature, the age of the battery, and the power-saving features implemented.
A NiMh battery has a similar discharge curve to a NiCad, with a sharp drop of available power as the battery approaches discharge. This drop is predictable, and system software will give the user adequate warning to recharge or replace the battery before full discharge.
The terminals on the NiMh battery are more recessed than those on the NiCads, and there is little likelihood of an accidental external short. The batteries will ship with a case to ensure that nothing damages the battery or the customer.
Precautions
Nickel-metal hydride batteries requires certain precautions:
* Because the self-discharge rate of a stored battery is approximately twice that of a NiCad, stored batteries must be frequently recharged.
* A NiMh battery is much more sensitive to temperature, especially high temperatures (over 40 degrees C). Approximately 50% of the battery capacity will remain if the battery has been stored for 14 days at 40 degrees C. If left for months at this temperature, the battery could be permanently damaged. Charging NiHy batteries below 5 degrees C can also cause irreversible damage to the battery.
* Overcharging, or over-discharging, will cause permanent battery damage. Due to this sensitivity, a special power management chip was built into the PowerBook Duo to control charging and discharging. The chip will also stop charging when the battery temperature exceeds a specific value.
Battery Charging
A NiMh battery, like a NiCad, should be fully discharged in order to obtain a full charge. To maximize battery life, fully discharge and then recharge the battery once every 30 days. This should be done any time you note that the run time of the battery has decreased. With proper care, a battery should last for at least a year.
It should take about two hours to charge a fully depleted battery with the computer shut down or in sleep.
Specifications
Maximum dimensions
17.8 x 77.8 x 106 cm
0.7 x 3.06 x 0.17 in
Maximum weight .75 lb
Battery capacity approximately 900 to 950 mAh
Operating Temperature 0 - 45íC
Disposal
At this time, only Nickel Cadmium (NiCd) batteries may be returned to an Apple authorized dealer for return to Apple. Other batteries should not be returned to the dealer or to Apple.
We recommend that non-NiCd batteries be disposed of according to local environmental requirements. In some jurisdictions, local recycling programs or other battery collection programs exist. Call your local or regional solid waste agency or recycling organizations to find out about battery disposal options in your area.