[RE-wrenches] Inverter output "phasing"

[Max Balchowsky]

I have a system consisting of (4) 5200w sun power inverters that was producing about half of the expected power over about 5 months of production. The installer said everything on the roof was wired correctly and that they suspected the Utility meter was at fault. The historical production on the inverters indicate that for about 5 months the inverters show good production but the utility shows higher that expected usage. Utility engineers tested their equipment and determined everything working properly. After the 5 months and a few visits by the installer, working on the system, everything began working properly. The home owner has lost thousands of dollars in expected production. After looking the system over (short of pulling things apart that would void the installers warranty) I suspicion that the inverter outputs were not on the proper bus bars in the single phase panel. I remember a few years back we had a problem with (4) 2500 watt SMA inverters
 and I went to the site to find the L1 / L2 legs were not on matching bus bars, in other words, all the L1 leads on one bus bar and all the L2 leads on the other bus bar. Once properly arraigned, the output increased significantly. Has anyone had a similar problem?

Max Balchowsky
SEE Systems
760-403-6810