Hm. That is interesting. Do you walk on your panels? Do you have a picture? That has nothing to do with my problem here, but I am curious what it looks like since you have 7(!) glued to the boat.
I had the solar panel and controller on my old boat, but I was constantly on shorepower and didn't really get to use them very much (did not go sailing often with them). I did occasionally look at the amps, which always were low, but I always thought it was just because the batteries are obviously topped up or because the irish weather was shite.
In your second photo the panel is very curved. What we have found with flexible panels is that the flex in the panel is its downfall. If you buy a brand new flexible panel and glue it to a slightly curved deck, such that it bends just that once, you can expect reasonable performance from it. If you have that same panel as a roving panel, like you show in your photo, and it gets flexed on a regular basis, they are destroyed in fairly short order. The problem is micro cracking in the panel. This quickly diminishes the output and the more you bend it the worse it gets. I suspect that this is where you are.
Yes I walk on them occasionally - its a 50 foot cat so lots of space for them - 5 on the coach roof and 2 on the deck (plus 4x360w hard panels that make up the cockpit roof ) - its pi**ing down here currently so I wont venture out for photos. Currently getting 32w each from the front panels and 30 from each of the roof panels - in rain with mid grey skies.(Each of the hard panels is giving 76 w but they are twice the capacity so that suggests the flexi ones are about 15% less efficient but then the big panels are completely unobstructed but I think in actual rain this makes no difference)
Interesting to hear you conclusion to the why your panels don't work .. I've fitted loads of Renogy 50w as I mentioned before but always fitted flat or to a small curve and fixed . I have done a few on the bimini covers of boats for people with magnets but the larger 100 or 175 w panels and they seem to hold a single curve on taught canvas and still work well after 2-3 years (thats the longest I have data for)
How detailed do you want to go! When light (of an appropriate wavelength) shines on a panel it moves an electron out of its natural "place" and generates an electron-hole pair. In order to get useful work from the panel "the" electron has to make it to the contact on the panel (and "the" hole has to migrate towards the opposite contact) the current then flows through your circuit between those contacts so that the electron and hole can recombine and "normality" is restored, ready for the next photon to hit the panel and repeat the process. In crude terms when you heat the materials there are more electrons banging around in the panel (at a sub atomic level) and thus increased chance of the positive hole finding an electron which hasn't had to travel all the way through your circuit and therefore achieves nothing useful.
We have a roving flexible panel that is normally dumped over the thwart in the dinghy, taken out every time the dinghy is used and much abused in use. Lasted 7 years before I replaced when we broke the (non solar) corner off entirely.
Yes, I curved it to point more towards the sun, it was just a test to see if I get more out of it. I got 1.6a out of it, as you can see in the picture. That's why I took two pictures of the controler. One for each "position".
Ah okay, well on a cat you just have so much room. On a monohull this would be very complicated. Hence why I asked, but then I didn't know you had a cat so I guess the question isn't that relevant now.
Is no longer an issue since we built a hardtop to replace the sprayhood. We have 300W of framed panels going on top. They are good quality 24v panels purchased from Germany. Added to the existing 720w of panels mounted on the guardrails, we are pretty maxed out on solar.
voltage and ampere. V X A = WRigged up the 100w rigid one now, unfortunately, by the time I was done, the sun was pretty much gone, so we'll see tomorrow morning what the results are like and if I get more than 1.5 watts with that panel.
I wonder what possible causes there are for such a low outcome. If the panel would be shot, it wouldn't work at all. Maybe an issue with the cables? Connections are not loose on the pwm or battery, but as I briefly mentioned earlier, one of the panel plugs was broken (seemingly only the plastic) and I stuck it together and taped it. Maybe that was an issue?.
Or perhaps a faulty pwm?
The renogy pwm doesn't show wattage btw, only voltage and ampere. But tomorrow I'll make sure to take a note of it. Hoping for sun in the afternoon.
voltage and ampere. V X A = W
Very true.voltage and ampere. V X A = W
Maybe, but I just measured it and I am getting 22volts or so at the panel.
