OVERVIEW

This document provides essential information about batteries used in Toshiba portable computers.

Toshiba portable computers are generally powered by a rechargeable and replaceable Lithium Ion (Li-ion) battery. It may be easily removed for storage, and may be easily swapped with another battery for the same computer model -- a freshly-charged one, ideally.

The charging times and 'rundown' times for these batteries vary from computer to computer.These times are determined primarily by power requirements of the computer, the design and power rating of the AC adapter, and by the age, condition, and energy capacity of the battery.

The power requirement of a computer depends upon the total power consumption of all of its components. This power consumption varies depending upon several factors, including the current brightness level of the display screen, whether or not the hard drive and optical drive are spinning, and various settings that can be adjusted from the Windows Control Panel, as follows:

For Windows XP: Click the Windows Start button, then click Control Panel, Performance and Maintenance, and finally Toshiba Power Saver.

For Windows Vista: Click the Windows Start button, then click Control Panel, Mobile PC, and finally Power Options.

See your computer's User's Guide for more information on power management.

Battery energy capacity is rated in milliampere hours (mAh), and this energy rating is printed on a label affixed to the battery. The computer's battery will charge more quickly from the AC adapter when the computer is turned off. The computer may not charge the battery when the computer is on, if it's consuming power at or near its maximum rating.

All batteries have a limited lifespan, which is dependant upon the usage patterns, as well as limitations of the battery chemistry technology. Lithium Ion batteries in particular undergo a natural aging process whether they are in use or not ('sitting on the shelf').

Additional or replacement batteries may be obtained through Toshiba Direct, at http://accessories.toshiba.com or by calling 1-800-TOSHIBA. Batteries may also be obtained from any Toshiba dealer.

Earlier generations of Toshiba portable computers used Nickel Cadmium and Nickel Metal Hydride batteries.

Nickel Cadmium (Ni-Cad, Ni-Cd) batteries were used in the earliest Toshiba portables. This type of battery chemistry delivers power until the battery is almost completely exhausted, but it suffers from a "memory effect" which tends to prevent partially discharged batteries from accepting a full charge. Ni-Cad batteries are no longer used in portable computers.

Nickel Metal Hydride (Ni-MH) batteries supplanted Ni-Cad batteries in the early 1990s. They last 30-40% longer than Ni-Cad batteries, and exhibit much less "memory effect". Ni-MH batteries are considered to be less harmful to the environment than Ni-Cads. Beginning in the late 1990s, they were phased out in favor of batteries based on Lithium Ion technology.

As of early 2008, Lithium Ion batteries are used in all Toshiba portable computers.

Lithium Ion (Li-ion) batteries do not exhibit the "memory effect" noted above. Lithium Ion batteries are relatively expensive to manufacture, but Li-Ion technology offers twice the energy density of Ni-MH technology -- resulting in batteries that have a much better ratio of energy capacity to size and weight.

The RTC (CMOS) battery: Toshiba portable computers have one other battery: a small rechargeable battery named for the Real-Time Clock circuit that it powers. This battery maintains the computer's date, time and BIOS setup settings. When fully-charged, this battery maintains this information for approximately 1 month after the computer is unplugged. The RTC battery is charged when the computer is ON. It typically lasts for several years, and should be replaced only by a Toshiba Authorized Service Provider.
 
To locate a Toshiba Authorized Service Provider (ASP), visit Toshiba's Global ASP Locator at http://pcrepair.toshiba.com -- or call 800-457-7777.

Avoid frequently disconnecting and reconnecting the AC adapter to the computer, which can overcharge the battery and reduce its lifespan.

If you will not be using the computer for more than a week, charge the battery about half-way, and remove it from the computer, to limit how far it discharges.

Use the correct AC adapter for your computer. Toshiba AC adapters are designed to power specific models of Toshiba portable computers.

Toshiba computers have a label on the bottom that displays the exact voltage and minimum amperage required to power the computer ("DC15V 3.0A", for example, which means 15 volts DC (direct current), at 3.0 amps. Each Toshiba AC adapter has a label indicating its output voltage and amperage capacity (for example, "DC15V 3.0A"). Important considerations for using AC adapters with portable computers:

The connectors must be compatible -- they must mate together correctly.

The voltage level must match exactly (a computer designed to run from 15 volts can be powered only by an adapter rated to produce 15 volts). If the AC adapter's voltage is higher than the computer's requirement, the computer and the battery may be damaged, If the AC adapter's voltage is lower, the computer may not operate correctly, or not operate at all.

The AC adapter must supply at least enough amperage (current) to meet the computer's amperage requirement. Otherwise, the computer may not run properly, the battery may not charge correctly, or may charge very slowly.

The quality of the power (ripple, noise and other factors) provided by the AC adapter must be very high. AC adapters from other manufacturers may supply sufficient amperage at the correct voltage level but the quality of the power may be poor, which can cause the computer to operate erratically, and could even cause damage to the computer. Whenever possible, use the correct Toshiba AC adapter for your computer.

The computer's power light may blink to indicate that there's a problem with the power from the AC adapter.

Use the computer's power saving features. The length of time a portable computer will run from its battery can be dramatically increased by simply decreasing any or all of the following: screen brightness, processor speed, the time out value for the hard disk drive. Explore the several other options in the Windows Control Panel for reducing the power consumption of the computer. See the User's Guide for the computer for more advice about the power-saving features of both the computer and the Windows operating system. See also Support Bulletin 98081123 Toshiba Power Saver / Power Management: troubleshooting, feature descriptions .

The computer may run longer from its battery if you disconnect devices and accessories that are not in use, including PC Cards and USB products.

Consider turning off (of reducing the frequency of) the Auto Save feature in applications (Microsoft Word, for example). This feature automatically saves your open document at regular internals, at the cost of the energy it takes to wake up the CPU and spin up the hard disk drive.

Don't expose the battery to excessive heat. The battery can be permanently damaged by high temperatures. A battery left in a car in the hot summer sun can easily be damaged by heat.

Use an additional battery or batteries to double or triple the length of time you can use your portable computer from battery power.

For information about proper disposal of old or damaged batteries, see Support Bulletin 94110001 Battery Disposal.

This is a normal consequence of the battery being in need of a fresh charge. For best results, allow the computer to charge the battery for about 24 hours before turning on the computer.

Batteries discharge whenever they are not being charged. Even when the computer is turned off, it draws some energy from the battery. A battery that has been removed from the computer will  slowly self-discharge, limiting its "shelf life".

Q: The computer's Power Meter shows 100% charge and the battery light is green, indicating that my battery is fully charged, but the computer doesn't run for very long. Why?

All batteries, of every type, are consumable products. They are able to store and deliver electrical power for some period of time, often a few years, before they need to be replaced.

It's also possible that the battery and the Power Meter utility have become unsynchronized. Follow these steps to correct this condition:

1. Charge the battery until the battery light changes from amber to green.
2. Remove the battery, and then re-insert it.
3. Continue charging the battery until the battery light turns green once again.

Ni-MH batteries / memory effect

The Nickel Cadmium and Nickel Metal Hydride batteries previously used in Toshiba portable computers can gradually lose their ability to accept a full charge; it may become possible to charge them only to the level at which they were previously discharged.

To prevent this "memory effect" with Ni-Cad and Ni-MH batteries, fully discharge them before recharging them, as often as possible. After fully recharging the battery, unplug the AC Adapter and run the computer until it runs out of power and shuts itself off.

The memory effect can be undone to some extent, unless the battery is damaged or near the end of its lifespan.

Following these steps to condition a Nickel Metal Hydride battery may at least partly undo any memory effect.

1. Turn off the computer's power saving features.

2. Unplug the AC adapter from the computer.

3.Turn the computer on and let it run until it shuts itself off. Playing an audio CD is a good way to speed up the battery discharge.

4. Charge the battery until the battery light changes from amber to green.

5. Remove the battery for 30 seconds, and then re-insert it.

6. Continue charging the battery until the battery light turns green once again.

Repeat this procedure two or three times, then turn the computer's power saving features back on.

Li-Ion batteries are not subject to this memory effect, but Toshiba recommends running the computer from the battery at least occasionally, even when the AC power is always available to run the computer.

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