Non-Invasive Battery State-of-Charge Sensor

The operational readiness of critical equipment often depends on the integrity of the battery subsystem. A small magnitude magnetic field, generated by a coil, can be used to monitor the state-of-charge and possibley long-term state-of-health of batteries. The proposed work will determine the feasibility of using a non-invasive sensor-external to a battery - and not connected to it's terminals. Sensor signals will be evaluated on lithium-sulfurdioxide and valve regulated lead-acid (VRLA) batteries under a variety of battery operating conditions to verify that the observed sensor response is proportional to the state-of-charge. Algorithms will be developed and refined that relate the sensor signal to the amount of capacity remaining in a battery. Long-term data trends may give an indication of "battery health" trends for predictive maintenance. Key factors for Phase II development will be identified. New sensors will be designed and battery monitoring system architecture proposed during the interim period between Phase I and Phase II.