A newly developed balloon-borne instrument contains electric and magnetic sensors for determining how lightning alters electric field vectors relative to a coordinate system fixed with the Earth. By combining data from this instrument with results from the compact Lightning Mapping Array (LMA) at Langmuir Laboratory in central New Mexico and the National Lightning Detection Network (NLDN), charge transported to ground by several strokes in a cloud-to-ground (CG) lightning flash can be quantified. As the flash progresses, the locations of the charge centers drained by successive strokes are seen to move further from the ground-strike point. Using this new instrument and two different models to map LMA source points onto charge centers, the charge transported in an intracloud (IC) flash is also estimated. Details of the instrument design and data analysis are also presented.