Patent ID: 7126310

Claim:
A method for balancing charge levels comprising: using a battery pack having a plurality of cells arranged in series; bridging around a first cell of the plurality of cells with a bypass resistor and a switch; monitoring a charge level of one of the cells based upon an input connected across the first cell, including comparing a relative voltage potential across the first cell with respect to a reference voltage potential and wherein the step of comparing includes providing cell monitor/regulator includes a voltage divider connected across the first cell and having an output connected to a first input of the comparator, and a reference voltage source that outputs the voltage potential to a second input of the comparator; closing the switch when the charge level of the first cell equals a maximum value so as to shunt charge current around the cell through the bypass resistor; connecting an output of the comparator to a lead of the switch, the switch closing a path through the bridge when the comparator measures a voltage at the second input greater than a voltage at the first input; saturating a transistor in response to an output of the comparator when the comparator measures a voltage at the second input greater than a voltage at the first input; and locating battery pack terminals at respective opposing ends of the series of the plurality of the cells, and connecting respective opposing leads of a charging circuit to the terminals at predetermined times so as to charge the plurality of cells.