Originally Posted by bill good
Just be aware these are 12v panels only. The better choice would be the higher 37v panels like used in the normal house solar install.
37v panels are identical to two "12v" panels connected in series. The only difference is the higher voltage panel is housed in one frame.
If two "12v" panels are connected in series and placed together they will be identical to single
larger 37v panel of the same wattage (assuming the other characteristics of the cells such as temperature coefficients etc are the same)
If parallel connection is best for "12v" panels it is even more important that higher voltage panels are connected in parallel.
All solar panels
that a boat is likely to use will have (or should have, some of the very cheap
no name panels have been known to leave them out)) bypass diodes. Their primary purpose is to protect the cells from overheating
if there is partial shade, but they do increase the output especially in series. If you use series connection adding an extra bypass diode around the whole panel is sensible.
connection is too slow to see the video, but they should indicate the properties of the panels they are testing. If there are no bypass diodes that will effect the results.
I still have an open mind, but I think most of the evidence points to parallel connection as superior to series connection on a boat providing the wiring
is adequate. If this is true if also indicates, if all other things are equal, "12v" panels are superior to higher voltage panels. Of course things are not equal, high efficiency large 12v panels are not produced.
It is also possible that a combination of series and parallel connection of solar panels
is best. It is worth rembering the individual cells in solar panels are connected in series so technically even if we wire the panels up in a parallel we actually have the solar cells arranged in a series/parallel configuration.
The question we should be really asking is what is the optimum number of solar cells that we should be connecting in series. It is unlikely that the correct answer is always 36 (as occurs in a "12v"panel). If we knew this ideal number of cells we could wire up both 12V and high voltage panels to be as close as possible to this optimum.
I started this thread almost 5 years ago and it surprising given the widespread use of solar on yachts that we still do not have a definitive answer.