In order to keep up with new networking needs, it is necessary to adopt mechanisms for charging network usage in a universal way. The Secure Charging Protocol (SCP) aims at answering this complex authentication, authorization, accounting and charging (AAAC) problem. SCP fits business models especially adequate for ad-hoc networks. This document discusses SCP as a possible solution to the AAAC problems in MANETs and presents the improvements made to this protocol in terms of Quality of Service (QoS). An implementation of this protocol on PDAs and the results achieved are discussed.