Battery gas gauge

An electronic device comprising:

• a storage medium having stored therein instructions that when executed by a machine result in the following:
• opening a battery cell circuit during a first and second time interval, said battery cell circuit comprising a battery cell;
• measuring a first instantaneous open circuit voltage level of said battery cell during said first time interval and a second instantaneous open circuit voltage level of said battery cell during said second time interval;
• correlating said first instantaneous open circuit voltage level to a first estimated value and said second instantaneous open circuit voltage level to a second estimated value;
• correlating said first estimated value to a first relative state of charge level of said battery cell and said second estimated value to a second relative state of charge level of said battery cell;
• and
• calculating a first full capacity level of said battery cell in response to a difference between said first and second relative state of charge levels.

A battery gas gauge circuit comprising:

• a switch network for coupling to a plurality of battery cells;
• an analog to digital converter (ADC) coupled to said switch network, said ADC adapted to accept an analog signal from each of a plurality of battery cells via said switch network and convert each said analog signal to an associated digital signal;
• and
• a processor capable of executing instructions stored in a storage medium to result in the following:
• instructing said switch network to open a battery cell circuit comprising one of said plurality of battery cells during a first and second time interval;
• instructing said switch network to couple terminals of said one of said plurality of battery cells to said ADC, said ADC adapted to provide said processor a first digital signal representative of a first instantaneous open circuit voltage level of said battery cell during said circuit time interval and a second digital signal representative of a second instantaneous open circuit voltage level of said battery cell during said second time interval;
• correlating said first digital signal to a first estimated value and said second digital signal to a second estimated value;
• correlating said first estimated value to a first relative state of charge level of said battery cell and said second estimated value to a second relative state of charge level of said battery cell;
• and
• calculating a first full capacity level of said battery cell in response to a difference between said first and second relative state of charge levels.