Sun Electronics sent me another panel to replace the one that was damaged, as I've reported before. It was shipped via UPS in a nicely-fitting cardboard box, with cardboard and styrofoam panels inside, and arrived safely. It is not clear yet what they will want me to do with the damaged one.
But, there is a problem with the replacement one: although both are labeled "Sun 90", they are different in both physical size and electrical characteristics. Here is the label on the one that was damaged, as I reported before it had a different junction box than the other 3 that arrived in my order of 4, but it had the same size and voltage / current specs as the other 3:
And here is the label on the replacement one:
And here are the two panels side by side:
One of the attractive features of the Sun-100 that I originally tried to order was the high efficiency, i.e., high wattage relative to the physical size. They ran out of those, but offered the Sun-90 instead, with same size but 10% lower wattage, and (back then) a 10% lower price. I accepted. Now this replacement one seems to be made from the same type of cells, but the frame is about 15% longer. This takes up more space, and in case of a multi-panel installation, does not fit right with the others. Also, I wanted the panels as advertised because they had a relatively low voltage at the max-power point, a plus if you are using a 12V battery and a simple (non-MPPT) charge controller: the extra voltage is then wasted, so it is better to have lower voltage (up to a point) and higher current. The promised specs of the Sun-90 were like it says the label on the old panel: max power at 17.6V, 5.12A. The replacement panel label says 18.8V 4.82A - that's 6% less current, and also 6% less power (with a simple controller). Also, if installed as a group with the other panels some power from the other panels may be wasted due to the mismatch. Especially so if connected in series, where the panel with the lower amperage will limit the overall current?
Sigh. So, should I yet again ask for a replacement?
