I guess I may have played it a bit too safe by under panelling my system for my mppt.
I have 415w Trina panels that are rated 50v oc, and the mppt is RS 450/100
I installed 7 panels per string (there was room on the roof for 8) and now since commissioning the system I'm getting a maximum system voltage per string of only 290v that's 160v less that the mppt is rated for. I understand it varies with temperature, but at the moment it's not that warm, and uk winters especially in Wales are never that cold. So would it be beneficial to add that 8th panel to the string, adding another 50voc to the system? I used the mppt calculator and it said to use 7 panels, but now I'm wondering if I was too conservative.