This is a three-part series, where the numerical  discrete-time analysis and comparative analysis of 72 Ah,Lithium Ion Battery (LIB) is presented. The numerical analysis has been explained in detailed with two non-linear Kalman filter varients, namely Unscented Kalman Filter(UKF) and Extended Kalman Filter(EKF), both in combination with event based Kalman Filter algorithm. The discrete-time state equations have been developed for 8RC equivalent circuit model, to model any variant of LIB, irrespective of recommended application type. LIB has been modeled with 8 parallel RC branches with also taking into account various non-linear parameters,thermal(modeled with thermal mass, convection, ambient temperature variation),battery charge-disharge cycle degration effect and aging. The comparative results have been tabulated from 1 RC to 8 RC and compared with experimentally measured. 400 cells are arranged to give 72 Ah, where each cell has rating of 6.66 Wh. In the first part, the UKF algoritm along with event-based kalman filter has been explained with the derivation of equations.I m not completing research paper, the earlier version got lost in computer crash. One part is survived, uploaded it.I will not re-write or submit paper as left R&D.