Why doesn't my Windows 2000 laptop with two batteries sound the low/critical power alarms?

A. The algorithm Win2K uses to calculate the amount of remaining time if you have two batteries is incorrect. The algorithm should be

Remaining time = (RemainingCapacity1 + RemainingCapacity2) / 
(PresentRate1 + PresentRate2)

This algorithm simply says that the amount of time left is the total capacity left of both batteries divided by the rate at which they are being used.

The actual algorithm Win2K uses is

Remaining time = (RemainingCapacity1 + RemainingCapacity2) / 
(PresentRate1)

The system calculates remaining time based on the use rate for one battery, so the system thinks you have much longer left than you actually have. To work around this bug, set your alarms at a higher power percentage level.