Hi all, I was called out this week to trouble shoot a system I didn't install. It's a five year old 1.44kW system with the following: Sun Tie ST 1500 inverter and 12 Astro Power modules. It only produced 634kWh last year. With our sun here, the shading, orientation, equipment, etc. it should have produced around 1123kWh.
I've heard a lot about Sun Tie failures, but don't know the details. What are the common failure modes? Is it likely that a failure of the Sun Tie would leave it operating, but only producing half what it should? When I showed up the system was producing 950W on a relatively sunny day - seemed pretty reasonable. After restarting the inverter it only produced around 150W. Is the MPPT very, very slow to find that sweet spot, or what was going on there? The system is comprised of three strings of 4 modules each. When I was there all three strings were producing about the same current, so that leads me to believe it's not a module failure. To make things more fun, the modules were installed at two different orientations. One string is at 38d slope, 30d east of true south, while the other two are at 36d slope, 75k east of true south. This certainly has a detrimental impact on the performance, but it doesn't seem to me that it could account for all of that energy loss. Thoughts? Thanks a lot! Dana -- Dana Brandt Ecotech Energy Systems, LLC www.ecotechenergy.com [EMAIL PROTECTED] 360.510.0433 _______________________________________________ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
