NOVELTY - The method involves positioning a primary coil along a portion of a battery. A secondary coil is positioned along another portion of the battery. The primary coil is excited with a signal. An induced alternating current electromagnetic field is measured in the secondary coil by the excited primary coil, where the measured electromagnetic field correlates with health state of the battery during operation. The latter portion of the battery opposes the former portion of the battery, where the induced electromagnetic field is perpendicular to an electric field between electrodes in the battery.    USE - Method for determining health of a battery e.g. lead acid battery, lithium-ion battery and sealed lead acid battery, during operation (all claimed).    ADVANTAGE - The method enables improving the real time or run time battery health or degradation. The method enables providing accurate health indication to prevent a critical condition during actual run-time of a battery. The method enables improving the system performance and reducing cost. The method enables improving battery magnetic linkage compared to air due to the presence of H+ protons in the electrolyte. The method enables providing internal electric field through the battery electrodes, thus providing a free path for magnetic flux lines to pass through the electrolyte and enhancing magnetic flux linkage. The method enables reducing the electrode surface active mass for chemical reaction during battery charging/discharging leading to premature capacity loss.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for the following:    (1) a system for monitoring a battery    (2) a non-invasive magnetic field probing method for monitoring a battery.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of a beginning state of H+ proton concentration during charging and discharging at the node positions.    Solid arrow (170)    Dashed arrow (171)    Source node (174)    Sink node (176)