I took a different approach to the "Coulomb Count" method for several
reasons.

1.  Temperature and load have a significant impact on the battery
capacity (number of Coulombs available)  Neither could be controlled in
my application.

2.  Batteries vary from one unit to the next, especially if you can't
predict the manufacturer.

3.  Battery capacity increases regularly (at least every few years).

4.  I had neither the room nor the money for a special battery monitor
chip.

My approach was to measure the voltage and temperature under light load,
then go into a lookup table to get the remaining battery life.  The table
was generated manually from graphs published by Duracell.  They have
great info available on their batteries, and they are the recommended
batteries for our product.

Don Burdette
dlburdette@juno.com