Toshiba laptops typically use 3 separate types of batteries.
1) RTC (Real Time Clock) battery
This rechargeable battery's purpose is to maintain the time, date and CMOS Setup information for the computer. When it is fully-charged, this battery will maintain its information for approximately 1 month or more, after the computer is unplugged and both the
2) Backup battery
This rechargeable battery keeps the computer's memory 'alive' during when the computer is in the Standby mode. When it is fully charged, the Backup battery can hold data for approximately 4-8 days after the Main battery has been fully discharged. This battery also receives its charge through the Main Battery and, like the RTC battery, should last for several years.
Note: In a few models the RTC and Backup were packaged together and called a sub-battery.
The Main Battery provides the power to operate the computer and it also charges both the RTC Battery and the Backup Battery. The Main Battery can be easily removed for storage for swapping with another Main Battery. The charging times and "rundown" times for the Main Battery varies from model to model and these times are determined by power requirements of the computer and by the capacity and composition of the battery (Nickel Cadmium, Nickel Metal Hydride or Lithium Ion).
The Main battery will always charge more quickly when the computer is plugged in to a mains power supply but with the computer turned off, though in most Toshiba models the battery will also be charged when the computer is plugged in and turned on.
Exceptions: The Satellite 1605, 1625, 1675, 1695 models only charge when the unit is powered off.
The Main Battery, unlike the RTC and Backup Battery, has a more limited lifetime, which is dependant upon the pattern of the batteries usage, and its composition.
What kind of Main batteries are used in Toshiba portables?
Toshiba has used three different types (chemical compositions) of Main Batteries: Nickel Cadmium, Nickel Metal Hydride and Lithium Ion. Nickel Cadmium (Ni-Cd) batteries were used in many of the early Toshiba portables. In the past few years, however, more powerful and lighter weight Nickel Metal Hydride (Ni-MH) and Lithium Ion (Li-ion) batteries have been built into in Toshiba portables.
Nickel Cadmium (Ni-Cd):
No longer used in Toshiba portable Computers, although at one time the most popular type of rechargeable battery used in portable computers, Toshiba no longer offers models that use this technology. Nickel Cadmium batteries tended to suffer from what was called "memory effect", but Nickel Cadmium batteries offered high performance, and delivered usable power until the battery had been almost completely exhausted.
Nickel Metal Hydride (Ni-MH):
The Nickle Metal Hydride has been used in recent Toshiba portables as well as many past models. Nickel Metal Hydride batteries last 30% to 40% longer than Nickel Cadmium batteries, and exhibit much less of the "memory effect" seen in Ni-Cads. The Nickel Metal Hydride battery is generally considered more environmentally-friendly than Nickel Cadmium batteries, and they cost less to produce than the newer Lithium Ion batteries.
Lithium Ion (Li-ion):
Currently the most widely available rechargeable battery, Lithium Ion batteries exhibit no "memory effect" (see below). These batteries have twice the energy density of Nickel Metal Hydride, so they can weigh as much as 30% less. Although more expensive and more difficult to manufacture, Lithium Ion batteries' light weight and relatively long life make them an excellent choice for many types of portable electronic devices. Lithium Ion batteries are now used in most Toshiba portables.
Details as an excerpt from Toshiba Document Number 98080633, released 28/05/2003 and last updated on 05/06/2004
No comments:
Post a Comment