The developer of PVsyst, André Mermoud wrote to me in response to my recent post:  Backtracking Issues in PVsyst.  He pointed out that my description of the problem we not entirely correct.  I encouraged him to document the issue on his website so that users have accurate information when using PVsyst to simulate tracking PV systems.  He posted a FAQ on this issue on July 2nd (  If you simulate tracking systems in PVsyst.  I encourage you to read his post and understand how this issue may affect your simulations.  Thank you to André for explaining the issue!

Feel free to pass on interesting PV performance modeling related issues to be included in future posts.  We currently have over 700 members in the PVPMC!  These blog posts are a great way to inform modelers around the world about news and issues on interest to this community.