Electric properties and the charging mechanism were studied for solutions of heptane with various concentration of the surfactant poly(isobutylene succinmide) (PIBS) by two independent methods, which are Total Internal Reflection Microscopy (TIRM) method and polarization method. The Debye length measurement from these two methods is within ±2 %. This good agreement lends credibility to both techniques. With TIRM measurements we evaluated the ionic concentration of charged micelles in these solutions, which varies from 0.1×10-3 mM to 2×10-3 mM increasing with increasing concentration of PIBS. With polarization measurement we deduced the diameter of micelles is around 40 nm and the actual dissociation degree of micelles is around 22-28 %. The dissociation degree in these solutions appears to be independent of the total concentration of PIBS, which is consistent with a mechanism in which the charged micelles are created by the bimolecular collision of two neutral micelles.