So as previously mentioned, the power solution is a solar panel, charge controller and storage battery.

Storage

The first item I bought for the power solution was the battery. I did some napkin level calculations and decided that the system on full load would be between 3A and 5A, and I would want somewhere in the region of 3 to 5 hours of runtime per night. I made an assumption that in central Florida we would not get so many consecutive days of no sunshine that I would need storage for weeks on end.

Based on these numbers, the battery would need to store between 9Ah and 25Ah for a single nights worth of illumination. With the battery shop around the corner, I went in with these numbers in mind, and decided on a 20Ah deep cycle AGM sealed lead acid battery.

Test runs seemed to indicate that this battery would run the lights for far longer than originally desired, but this is not a bad thing, the remaining power would simply help on those days when it wasn't sunny.

Solar

Once the battery was sized it came time to choose a solar system. Based on the geographical orientation of the dock, its roof and the nearby trees, along with the traditional summer weather patterns, I decided that it was beneficial to size the panel to get the charging done as early as possible in the morning.

After observing the insolation levels for a while, I reckoned to have about 5-7 hours at various incidence angles.

Assuming that the battery will give out its full 20Ah at 12v (and I will use all of that capacity each night), the consumption will be 240Wh per night. Based on the worse case 5 hours of usable sunshine per day, that means I would need 48W of panel to replace all of that power. If you make another assumption that the panel will work at on average 50% maximum rated output, your panel requirements are 96W which is conveniently close to a standard 100W panel. I swear I did this math before I bought the panel!

As you can see, there have been a lot of assumptions and estimations, but the hope is that by erring on the pessimistic side, the battery will be fully charged in all but the very worst of conditions.

For the solar system I scoured Ebay for sellers of complete systems, working on the premise that they are more likely to work together, I came up with this device (if the link stops working search for 100W, 12v solar system).

I would recommend this seller specifically due to my experience, unfortunately the panel arrived with the front glass shattered. I took a picture and asked the seller what could be done about it, he immediately shipped a new one at his expense, and told me to keep the broken one. There are plenty of results on google when you search "repair shattered solar panel" and on testing them, they are both producing about the same power.

Distribution

For power distribution, I went looking at resistances and voltage drops of various cabling sizes. Again fortunately I live and work near a store that carried all sorts of cabling, in different sizes and colours. I decided that for the higher current paths I would use 12 gauge wire and that would reduce to 18 gauge for individual controllers.

I designated wire to an individual controller as low current, and anything around the battery and panel up to that point as high current. I also made a preference for wiring under the dock to be heavier gauge too. I am pretty sure I have over specified the wiring, but this is another case where I'd rather have too much than too little.

I also designed in fuses to protect the various circuits from shorts and other craziness.