Standard test procedures, ''IEEE P1526/D1 Draft Recommended Practice for Testing the Performance of Stand-Alone Photovoltaic Systems,'' [1] have been developed to assess the performance of stand-alone PV systems tested outdoors under prevailing conditions. A copy of the procedures is included in Appendix E. This report presents an overview of the procedures and results from three validation tests conducted between January 1999 and September 2000 at one European and four US test sites. There was good measurement agreement between the results measured at different test sites on similar systems. To date, most PV system performance test procedures have looked at the performance of the individual components and have not addressed how the integrated system works as a whole. The performance test procedures described in this report verify that the system and load operate as expected, ensure that the PV array and system are capable of recharging the battery, determine the usable battery capacity (UBC), and determine if there is any significant change in the UBC measured three different times during the procedures. The procedures have been submitted to both IEEE SCC21 and IEC TC82 for use in developing standards. The IEEE SCC21 has initiated P1526, ''Recommended Practice for Testing the Performance of Stand-Alone Photovoltaic Systems,'' [1] and the IEC TC82 has initiated Standard 62124, ''Photovoltaic Stand-Alone Systems Design Qualification and Type Approval'' [2]. The IEC document also addresses indoor testing.