I've built a number of portable photovoltaic power systems for a variety of uses. Primary I use it for either running communications or computer equipment, or charging cordless tools. I've got several old UniSolar 64Watt unbreakable panels that use for this purposes, as usually I'm off-road on rough terrain.
The main thing all these systems have in common is that they are portable to the point of being able to carry everything by hand when need be. (which I've done) I've even carried (using a sled or backpack) system to the tops of mountains, some over 11,000 feet.
This sized system is nice towork on because they are so simple. If you ever plan to do major building or renovating of your off-grid house, it's good to play with something this size.
So people ask me, why do you have a solar panel on the roof of your truck ? They I explain that I spend alot of time in the field every year, and somebody has to be able to charge batteries and run equipment. I used to just carry the panel around in the back of my truck, but that got to be a hassle after several days of camping when you move sites every day.
The one big advantage of that technique was that with a 30foot cord, I could maximize the solar input by moving the panel around, and setting a good angle. Mounting it to the roof, directly to my Yakima rack, turned out to be a good compromise, although it encourages one to park in sunny spots.
I originally started by using a system with 2, 6V Surette 460 batteries, and a 20Amp Lyncom charge controller, that came off another project that had been running my wireless phone system. Now I just use either a Satellite phone or VOIP over my wireless broadband connection. Using this system got to be a bit of a pain, as everything ws mostly just thrown in the back of my truck, so I had to be careful of it.
Eventually those batteries died of old age, so I upgraded the whole system with a new 12V Surette deep cycle battery, and added both multiple cigarette lighter outlets, and a small 300Watt inverter. The inverter is horribly inefficient. but I rarely use it. I'm one of those weird people that owns 12VDC car chargers for most all my equipment.
This time I also bothered to bolt or glue everything to a board, and get the wires under control. I use an old metal milk crate to hold my truck tire chains and jumper cables, so with the board mounted on top. As I sleep in the back of the truck, it now makes a nice table. Since I also added an LED track light on the roof, it makes my truck completely livable for long periods.
It's still a bit crowded, and I still have to be careful as everything is exposed. I doubt any of these systems would be up to code, but their entire purpose is to be inexpensive, and of course, portable. I still have to take this system out a few times a year and use it for other temporary projects.
Here's the wiring diagram, as you can see, it's very simple. I used Gnome Dia for my wiring diagram, as it lets me drag things around, and is simpler than the CAD software I usually use. I created a library of objects for the equipment to make it easier. You can get my Dia shape file off this website for your own use. Install this tarball in $HOME/.dia.
For more pictures of these portable power systems and more, go here.