============================================================================= AST RESEARCH, INC. TECHNICAL BULLETIN #0750 04-01-92 ============================================================================= PREMIUM EXEC NI-CAD BATTERY INFORMATION PROBLEM: All Nickel-Cadmium (Ni-Cad) rechargeable batteries have the inherent "memory" property that can cause early low voltage indications and premature system shutdown. CAUSE: When a Ni-Cad battery is put through repeated partial- discharge / recharge cycles, and is drained to approximately the same level each time - down to half capacity, for example - it develops a "memory" of this point in the discharge process. Once established, Ni-Cad memory distorts the battery's voltage output profile. The battery will produce a normal voltage until drained to the memorized location, but thereafter its voltage output abruptly sags to a sub-normal value, and stays below normal until actual battery depletion. The voltage depression can be deep enough to cause the Notebook to prematurely issue the low battery warning (audible beep and lighted amber LED) or battery fail warning (audible beep and blinking amber LED.) SOLUTION: The Ni-Cad battery "memory" effect can be corrected by "conditioning" the battery, a process which simply consists of fully discharging the battery before recharging. The battery pack should never be disturbed while the system is in use or while the battery is being charged. To remove or install a battery, the system should be powered down and the AC adapter removed. AST recommends conditioning the battery pack monthly to promote optimum performance. Conditioning of new, out-of-the- box Ni-Cad battery pack is also strongly recommended. Listed below are the steps required to correctly condition the Premium Exec Ni-Cad battery: 1. Charge the Ni-Cad battery up to full capacity. 2. Disconnect the AC adapter. 3. Configure the Notebook's Setup Menu as shown below. IMPORTANT: Note that Suspend must be ENABLED! Default Speed: HIGH Backlight Timeout: 0 Hard Disk Timeout: 0 Suspend: ENABLE Software Timeout: 0 (Exec SX-25 and SX-25 color only) Turbo Mode: ON AT BOOT Speaker: ENABLE Other Parameters: Don't care This configuration results in a near-maximum load on the battery during the first part of the conditioning process. Suspend mode then prevents an excessive drain rate as the battery nears depletion. 4. Store the setup menu setting and exit. The system will reboot and the screen will display the DOS prompt. 5. Keep the Notebook powered up with its LCD display open for 12 TO 24 HOURS. Most will find that overnight conditioning of the battery is the most convenient method. It is safe to use the Notebook in the normal fashion during the conditioning process. However, the following precautions must be observed: a. Save your work and exit all applications back to the DOS prompt immediately after the first low battery warning. Allow the Notebook to remain powered up with the LCD display open, however. b. A full 12 hours of on-time will insure complete battery discharge even with premature suspend activation caused by the "memory" effect. 6. After 12 hours, turn the Notebook off. Recharge the battery by attaching the AC adapter. Connect the AC adapter to the Notebook before plugging the adapter into the AC socket. Connecting the AC adapter in this sequence insures that the Notebook battery management system senses all signals on the DIN connector appropriately. NOTE: After completing a "fast discharge", wait at least 5 minutes before connecting the AC Adapter/Charger to recharge the battery. If this is not done, the AC Adapter/Charger could switch to Trickle Charge mode instead of Fast Charge mode.