The purpose of this paper is to provide some general characteristics concerning the coupling of a lab scale alkaline water electrolyser powered by a set of photovoltaic panels. A description of the different tests made on this system and the development of a program under Matlab for the simulation of direct coupling (photovoltaic panels - electrolyser) is provided. Experimental results provide practical information for the coupling of the panels and the electrolysis cells. The system efficiency is low because of the low efficiency of panels and also the mismatch between the panels and the electrolyser. The simulation results of the direct coupling with the various combinations of panels and the electrolyser cells according to the different levels of irradiation, shows the possibility to improve the system performances for a given power of panels. Copyright (C) 2010, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.