Small PV system
I use this small photovoltaic system to run the 12V electrical loads in my caravan. These consist of a pair of 8W fluorescent lights, a small "boom box" stereo, and a mobile phone charger.
A pair of cheap amorphous panels provide the power to the system. These have a claimed output of 10 watts, but the maximum I have seen actually going into the battery is about 1.2 Amps. They are connected to the battery by a length of cable intended for use with low-voltage garden lights. This is pretty good stuff to use for such systems, since it's cheap, has reasonably heavy conductors and thick UV-resistant insulation. I've put them on a pole mount, fixed at 45 degrees (which is a reasonable year-round compromise for my latitude, 45 Deg South).
Here's a view of the internals of the system (this fits under one of the seats. Most caravans sold in Australia are pre-wired with 12VDC and 240VAC circuits). On the left you can see a bundle of wires that connect to the tail lights (disconnected because this caravan isn't going to travel the road any more). The black cable coming through the hole in the floor is the input from the solar panels, the white one disappearing through the floor goes to a cigarette lighter socket for the boom box. The white cable heading off to the left feeds the 12V circuit for the van lights, the two black wires going to the right feed an additional light and a cigarette lighter socket on an extension lead that I use for my phone charger and suchlike.
The positive lead to the battery has a single 10A fuse, in order to keep things simple. Note that the way this is set up, if the fuse blows power will still be available for daytime loads on the system (well, up to the maximum output of the panels, anyway).
Here's a (rather blurry) view of the inside of the junction box. I've used a couple of small brass bus bars (I bought a bucket of them for $2 from a scrap metal dealer) to keep the connections reasonably neat. I'm using one side of a 35A bridge rectifier as a blocking diode, partly because it has easily connected spade lug terminals, but mostly because I had it on hand.
The system provides more than enough power to run two 8W fluoro lights for about 3 hours per night, the radio for a couple of hours per day, and to recharge my phone battery every couple of days. I also use the 20W incandescent lights int he van when I need more light over the stove or sink, but that's usually only for a few minutes at a time.
BTH