PV for Dummies... IT'S NOT THAT HARD!
I was asked to do this by another member, who while quite accomplished with Solar Thermal, had concluded that PV (Solar Electric) was too “hard” and complicated.
That's one of the things holding PV back, perception. In reality IT'S NOT THAT HARD!!! A basic (off grid) DC system like you might install in your boat or RV has only 3 components: solar panel, battery, and controller. The battery you probably already have, so that leaves TWO components. The solar panel only has two wires and yes they're marked. Most solar panels today already have polarized wires attached, so they're “plug and play”. However most modern solar panels have enough power to cook your battery, so you'll need a controller (think "battery charger"). The controller has connections for four wires or maybe six, and yes they're marked too. The battery, well you already know about batteries. That's all there is to it.
Here's a hypothetical project: Suppose you have a garden shed in your back yard which doesn't have electricity, and you're tired of groping around amongst the rakes, bugs, and snakes with a flashlight. Some lights would be nice so you can at least tell them you're coming. You have several options:
Simplest and probably the best would be to call a contractor and have him run power to the shed ($$$). Another way would be to run an extension cord from the house to the shed. Simple and it works, until one day you run over the cord with the lawnmower. Oops!
But rather than deal with the cord or the contractor. you decide to make a stand alone (off grid) electrical system. You go to Big Box and pick up a car battery (a “deep cycle” RV/Marine battery is better) , some 12v LED garden lights (it IS a garden shed after all), and some insulated wire. Up to a point, most any wire will do. You connect the lights to the wire and the wire to the battery. A switch would be good, and you can use a standard wall-mount switch from Big Box. For safety you install a fuse from the auto store. Now you simply open the door, flip the switch and watch the critters scatter.
This is all well and good except that after a few days the battery goes dead and the lights go out, because the battery isn't getting charged (bummer). All you need to fix that is a solar panel, a controller, and some more wire. You connect the controller to the battery and the solar panel to the controller, and find a place in the sun for the panel. Now whenever the sun shines, your battery gets recharged. Congratulations, you've just built your first PV system.
After a while you decide that while lights are fine, it would be nice to be able to run some tools. Most power tools take AC power, not the DC from the battery. While a 12v battery WILL run a power tool you will need an INVERTER to “invert” the DC from the 12v battery to AC and step up the voltage. The best inverters are “full sine wave” but in most cases the cheaper MSW or “modified square wave” will work. Your inverter (again) has two wires you connect to the battery. Now you have AC power to run small tools, simply plug them into the inverter. Big tools or appliances (table saw, beer cooler, AC) will require a bigger system. Not necessarily more complicated, just bigger (more batteries, more solar panels) That's how I started, but my “shed” was a boat.
That's OFF grid solar in a nutshell. ON grid is a different story, with lots more power, regulations, permits, and LETHAL voltages (not for the newbie).
Anyone who has questions or additional comments, go for it. That's why we're here.