I expect it only a remote possibility, but if anyone has interest in DIY-level floatovoltaics, I will report after two seasons of experience with my battery charging system. To review: This is a 100-watt semi-flexible panel bonded to an exercise mat that floats next to my sailboat while in its marina slip. Control is via Victron Energy MPPT 75/15 Solar Controller to 2X100Ah AGMs. The solar panel is partially shaded by the floating pier in early morning. Latitude DD is 46.677 N.
The components have held up well and the batteries continue to be charged to float level – at least whenever I have observed the status later in the day. There is no evidence so far for any delamination or degradation of the panel. There is also no evidence of stray electrical potential. The closed-cell foam pad has proved surprisingly durable and even seems to have some resistance to algae deposits and cleans off at season's end better than most things left submerged. The charging duty decreased during the second season because I no longer use the AGMs for propulsion. It becomes overkill for house needs, but the weight is equal to the lead ingot ballast that was removed, so they will stay for now.
Occasionally there can be flotsam that settles on top – as cpcanoesailor warned – but a good rain or a bit of hosing solves that easily. The main problems I faced were missed in the advice from this group. The floating panel just proved irresistible to critters. In the first season, a mallard gave a new meaning for poop deck. This duck was quite persistent and possessive. It paid little attention to the dogs on the dock or interested onlookers. Scaring it off with the hose was only a brief interruption to its sunning and defecating activities. Amazingly, even with a large deposit of duck poop, the panel kept producing.
For the second season, I fashioned a protective cover of bird netting. This successfully kept the ducks off, but late in the season, a (suspected) otter got curious and broke through the netting. I do not know whether it was the same otter or not, but I also found the rope that tethered the panel to the pier cleat to be severed on two occasions. This year, there will be new bird netting and a cut-resistant line.
I have queried the journalist who covered some of the efforts of students at Michigan Tech and the university to find out whether they ever progressed to field tests for their floating system. In the article, the students were performing tests in a swimming pool. I was curious about successful deterrents if my critter condition is common. No reply received. I would imagine this critter invasion could be a serious drawback to small or large arrays.
