PowerFilm folding panels have a maximum power transfer point that occurs somewhere around 15.4 volts. If the load can't absorb the power produced at that time, the panel voltage will increase -- you can expect to see somewhere between 18 and 20.5 volts as the load current approaches zero. Powerfilm themselves warns that a battery should not be used without some sort of charge regulator unless the system load is so high that the battery never approaches a 100% charge condition (which would allow the solar panel voltage to increase to the point where the battery was overcharged, or the attached equipment damaged).
http://www.powerfilmsolar.com/education/calculations/ I would suggest that anyone with a PowerFIlm panel producing 14.9 open circuit in full sun has a defective panel, and should contact PowerFilm about a replacement -- they are an excellent company and stand behind their products. I returned my 60 watt panel when the output current unexplainably dropped by about 25%. They quickly replaced it with a new panel. 73, Bob, WB4SON ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
