Hi Mark
A couple of notes.
In response to these statements....
The necessary components of a system are:
Solar panel(s)
Controller - to keep from frying the battery
Converter - to make the DC usable as AC
You start with batteries. To start with batteries, you need to decide on a system voltage. Here are some rough guidelines....
12V: small system that can power
lights, TV, computer, and other small home electronics
24V: medium system that can power all of the above, and also a refrigerator, freezer, microwave, some power tools, ect.
48V: large system that can be scaled to power anything, like 240V appliances, well-pumps, compressors, ect.
Golf-cart batteries are a good choice for starter systems. They are usually 6V, so you wire them in series to get the desired system voltage. So, to make a 24V system, you wire four 6V golf-carts in series to get 24V. Lithium batteries are coming into vogue now. They can be more deeply drained then lead-acid batteries, but do not handle cold well. Charging a Li battery at freezing will destroy it. You want to scale the battery size to your daily needs, plus accomodations for cloudy/rainy weather. Batteries are usually rated in Amphours, or Ah. You then multiply the Ah X your system voltage to get your Watthours. Say you have a 210Ah golf-cart battery at 24V. You've got 210Ah X 24V = 5040Wh of power. You don't want to drain lead-acid batteries greater than 50%, so that 5040Wh is actually 2520Wh (2.52kWh) of USEABLE power. You scale the battery to your daily needs. Don't get a 210Ah battery if you need 10kWh of power per day.
Solar panels can be divided into two groups, 12V, and high-voltage grid-tie. You'll pay the most money per watt for 12V panels, but can be coupled with cheaper PWM controllers to charge 12V batteries. Panels must be quite close to the batteries they are charging to prevent voltage drop. Grid-tie panels are cheaper per watt, but you need an MPPT controller to transform the higher panel voltage down to battery voltage. Larger grid-tie panels can be wired in series to >100+V and then the current ran hundreds of feet through thin copper wire without power loss. The very high raw solar then gets transformed down to battery voltage at the MPPT controller.
Controller: Two types, PWM and MPPT. PWM are very cheap but can only work with panels close to battery voltage. Can't increase the incoming amps. MPPT controllers act as a transformer to transform raw high solar voltage down to battery voltage, converting the extra volts into extra amps. They cost more though, sometimes a lot more. As a general rule of thumb is a break-even point of 300W. Below 300W, you spend the least money with PWM and 12V panels. Above 300W you spend the least money with MPPT and grid-tie panels.
Inverter: Do not say converter. A converter is a component that changes DC current of one voltage to DC current of another voltage, say from 24VDC down to 12VDC. An inverter changes low voltage battery DC into high voltage 120/240VAC. Low budget inverters only produce square-wave or modified sine-wave power. They are OK for things like lights, but will quickly burn out anything running an electric motor. Sine-wave inverters can run any appliance, such as power tools, refrigerators, freezers, air-conditioners, or anything else powered with an electric motor.
For my own system, I built single-pole rotating array mounts that are adjustable for both direction and angle. I rotate them by hand during the day. I adjust the seasonal angle just two times per year. I see much more power gain going east to west than I do summer to winter. Below is a pic of one of my arrays that can hold as much as 1500W of panels. What I do on the fly is to take a 12" piece of PVC pipe, and put it in front of the panel. When pointed directly at the sun, I can see the sun shinning through the central hole.
Panels typically can be pointed due south, though there can be exceptions depending on your individual location. To reduce the level of noon-time amps, some
people orient one array SE and another array SW. You get a lower noon-time peak, but a broader over-the-day power curve. Maybe the easiest thing you can do is just go outside with sheet of plywood, and just prop it up till it's facing the sun. Use the pipe-trick to optimize the angle, and then measure that angle with a protractor. That makes the math easier to stomach.
I'd say a serious off-grid
cabin system starts at 24V with ~1000W of panels. Something like that can run your whole cabin with a 21'st century lifestyle with about a 2000$ investment.