Patent ID: 7791347

Claim:
A system for use with an aircraft battery assembly, the system comprising: a valve-regulated lead-acid battery; a monitoring circuit configured to monitor the battery in situ, the monitoring circuit comprising: at least one sensor positioned to sense at least one property of the battery, wherein the at least one sensor comprises a Hall effect sensor positioned in parallel to the axis of a terminal of the battery to sense a current delivered by the battery; a processor in communication with the sensor; and an electronic memory in communication with the processor, wherein the memory comprises instructions that, when executed by the processor, cause the monitoring circuit configured to: receive operational data from the sensor; store the operational data at the electronic memory; a battery housing, wherein the battery and the monitoring circuit are positioned within the battery housing; and based at least on the operational data, derive an indicator of the battery's age selected from the group consisting of a number of starts and a number of charge/discharge cycles; and an external processing device in electronic communication with the monitoring circuit, wherein the external processing device is configured to: derive discharge function factors of the battery considering an age of the battery, wherein the age of the battery is derived from the operational data; and calculate a capacity of the battery considering a discharge function of the battery and the discharge function factors.