This subject actually belongs in more specialized fora, I know. But there are some clever people in this group, maybe someone knows some facts. Any references to good spcific answers on solar fora are welcome. But discussions of solar performance are usually not based on different panels in a system.


I like to use flexible solar panels on the boat, they are light and a catamaran usually has some space where they can be located. You can buy cheap ones and change them more often or buy really good ones at 3-4 times the price. I have done both. Now one of the cheap ones needs to be replaced. As time passes, solar panels slowly develope. The newer ones tend to have higher max power voltages (Vmp). All my solar panels are connected in parallel to one MPPT regulator. There is one panel of 16V Vmp. I am looking at replacing another and have found an interesting candidate that has Vmp 20.5V. The last figure is pretty high, most I see are 17-18V. Will this be a problem? Will the 20.5V panel kind of block out the others when operating in full sunlight? Or will the other panels "drag down" the 20.5V panel to supply a variable average voltage to the MPPT? Information on blocking diodes or not is hard to find regarding cheap flexible panels, so I presume they will normally not have such. And as far as I know diodes lower the efficiency of solar panels anyway.


The solar panels are installed in various positions on the boat, so all of them will never have optimum sunlight exposure at the same time. Thus the voltages provided by the individual panels will probably vary a lot also as the situation is today. So I am tempted to believe that the 20.5V panel will not be a problem, at least most of the time.