Adjacent battery cells connected in devices are balanced by closing a first circuit to charge an energy storage device from a first battery cell and thereafter simultaneously opening the first isolated switch and closing a second isolated switch to cause the energy storage device to charge a second battery cell. For example, one such lead frame structure may include a set of leads extending in a first direction and a dam bar. Changes in fluorescence of the compounds of formula 1 were analyzed by ratiometric approach using monomer and excimer emissions of the pyrene fluorophore to selectively signal the concentration of mercury ions.