I haven't done the calculations lately, but solar cells are a VERY expensive way to generate electricity. I decided against them about six years ago and decided if I were going to a passive power, I'd use a wind gen....and decided against it on esthetic reasons. Noise and appearance....Much as I would have liked, I could not find an alternative to my diesel genny that made even remote economic sense. You can easily see how expensive solar cells are by going to a solar supplier website of your choice and using their cost and average daily output and figure the costs. You'll also find that there are different types and efficiences....when I last investigated the top of the line (most expensive) seemed to make sense based on higher output. Their limited output power limits them to an auxiliary source on a typical powerboat. On the positive side, these are generally maintenance free and very long lived power sources. Rob Brueckner Hatteras YF