On Wed, Jul 29, 2020, 18:36 Willie via EV <ev@lists.evdl.org> wrote: > > > Perhaps you can comment on some trouble I've run into. > > After observing that some microinverters worked on battery input and > that string inverters worked well with combined strings of both east and > west facing panels, I became convinced that a single microinverter could > serve one east facing panel and one west facing panel. The two panels > connected in parallel to the microinverter. Tests were disappointing > with generally a microinverter, over a day, producing less energy than > had it been attached to either a single east facing panel or a single > west facing panel. Slopes on the panels are 15-20 deg from vertical so > that panels are shaded around 30% of the day and both E and W receive > sun about 30% of the day. It is semi-clear that even a shaded panel > interferes with production from the not shaded panel. > > String inverters can do "double duty", producing from east facing panels > early in the day and west facing panels late in the day. With a smooth > change over at mid-day. Microinverters seem unwilling to do that > "double duty".
Which microinverter model did you use? Were your solar modules identical? Which solar module model did you use? Were the solar modules facing completely opposite directions, true east and true west, i.e. truly 180 degrees apart? MPPT algorithms can get stuck at a local maximum point point instead of the global maximum point point along the complex I-V curve created by 2 parallel modules. Shading can also create complex I-V curves. Some string inverter brands (SMA) talk about how their products handling this situation better than the competition. *https://www.solarquotes.com.au/blog/sma-shadefix/ * https://www.sma-america.com/fileadmin/content/www.sma-america.com/Partners/Images/Knowledgebase/OptiTrac_Global_Peak/OPTITRACGPWP-UUS131010W.pdf With independent modules and independent MPPT, things are easy. When paralleled, the two modules will need to operate on a common voltage. The best power point voltage for one won't be the best for the other, except when both modules have identical illumination. At other times one module will be no longer at its personal peak. The question is whether or not the microinverter can find the highest peak overall. -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20200729/bbcdeb03/attachment.html> _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub ARCHIVE: http://www.evdl.org/archive/index.html INFO: http://lists.evdl.org/listinfo.cgi/ev-evdl.org Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA)
