Method and apparatus for operating a battery to avoid damage and maximize use of battery capacity by terminating battery discharge

A method for effecting termination of discharge of a battery to avoid damaging said battery and substantially maximize use of capacity of said battery;

• the method comprising the steps of:
• (a) periodically effecting a determination of capacity of said battery;
• said periodic determinations being effected at different ages of said battery;
• (b) storing a value representing at least a latest capacity result of said periodic determination of said capacity;
• (c) determining a battery voltage drawn from said battery;
• (d) during a monitored battery operation, integrating current flow from said battery with respect to time over a time interval to determine an integrated charge value at an end-of-interval-time substantially when said interval ends;
• (e) determining an extant depth of discharge at said end-of-interval-time;
• (f) in no particular order:
• (1) comparing said extant depth of discharge with a predetermined value of maximum depth of discharge;
• and
• (2) comparing said battery voltage with a predetermined value of battery voltage;
• (g) if said extant depth of discharge is neither within a first predetermined range of said predetermined value of maximum depth of discharge nor said battery voltage is within a second predetermined range of said predetermined value of battery voltage, carrying out steps (d) through (f);
• (h) if said extant depth of discharge is within a first predetermined range of said predetermined value of maximum depth of discharge or if said battery voltage is within a second predetermined range of said predetermined value of battery voltage, terminating said monitored battery operation.

An apparatus for controlling operation of a battery to terminate discharge of said battery to avoid damage to said battery and substantially maximize use of chemical capacity of said battery;

• the apparatus comprising:
• (a) a processing and control unit coupled with said battery;
• said processing and control unit determining a first depth of discharge of said battery while said battery is in a relaxed state before commencement of a first battery operation;
• said processing and control unit determining a second depth of discharge of said battery while said battery is in a relaxed state after completion of said first battery operation;
• (b) a first measuring unit coupled with said battery and with said processing and control unit;
• said first measuring unit determining current flow from said battery during said first battery operation;
• (c) a second measuring unit coupled with said battery and with said processing and control unit;
• said second measuring unit determining a battery voltage across said battery;
• said processing and control unit employing said first depth of discharge, said second depth of discharge and said current flow for determining maximum chemical capacity of said battery after completion of said first battery operation;
• during a next battery operation following said first battery operation, said processing and control unit integrating current flow from said battery with respect to time over a time interval to determine an integrated charge value at an end-of-interval-time substantially when said interval ends;
• said processing and control unit employing said maximum chemical capacity, said integrated charge value and said first depth of discharge to determine an extant depth of discharge at said end-of-interval-time;
• if said extant depth of discharge is neither within a first predetermined range of a predefined maximum depth of discharge nor said battery voltage is within a second predetermined range of a predefined minimum voltage, said processing and control unit cooperates with said first and second measuring units to determine a subsequent depth of discharge at a subsequent time;
• if said extant depth of discharge is within a first predetermined range of a predefined maximum depth of discharge or if said battery voltage is within a second predetermined range of a predefined minimum voltage, terminating said next battery operation.