Solar System Description:

A solar system consists of several components

A solar array, sometimes called a photo voltaic (PV) array. This consists of one or more solar panels wired together in one of several ways (discussed later).

Wire: The most overlooked part of the system. Do this part right and it will make a great deal of difference.

Solar Controller: Electricity from the solar panels must be regulated before it gets to the batteries or they will overcharge and be destroyed. The solar controller oversees the charging process.

Batteries: A very complex subject. There are lots of types, models and technologies to consider.

Inverter: The electricity in the solar system is DC or direct current. Many appliances need AC or alternating current. An inverter changes the DC to AC.

Metering: Although the system basically runs itself, you need to know how much power you have available and you need to monitor the system to detect any problems.

The components, one by one:

Solar Arrays:

Panel types:
There are several types of solar panels. Some of the characteristics include, power output per square inch, break ability, shadow performance , and cost,to name a few.

Basically they fall into two groups. I will call them Mono-crystalline (MC) and Thin Film (TF) .

Mono-crystalline(MC) are the most common type. The array consists of many individual cells wired together to form a panel. MC are cheaper and provide more power than Thin Film (TC) panels.

The disadvantages of MC are that they are more fragile, they do not have diodes between each cell and therefore have a severe power loss when even partially shaded and they do not produce as much energy when the sky is overcast or in other reduced light situations.

The cells are sandwiched between an aluminum support sheet and a tempered glass covering. They are rigid and although the tempered glass is pretty strong, can be (and frequently are) broken when used in the RV environment. The cells are mostly sensitive to visible light with limited production under ultraviolet and infrared light.

Thin Film(TF) panels are used in severe service environments. Marine and military applications are the most common. TF panels are one continuous multi-cell layer, sliced very thin and then bound with other thin films to produce a multi-layered surface.

Each cell within the film has a diode between it and the other cells. This diode greatly reduces the effect of shading. The thin film layers are flexible and can be put on rounded surfaces. They are covered with a very strong plastic protective layer. Mine have many large gouges and “pings” from hitting trees, dropped wrenches and other hazards that would have destroyed the glass covered MC panels.

The multi layers are sensitive to different wavelengths of light, allowing much better performance in overcasts where the amount of visible light is reduced but light of other wavelengths remain high.

There are two major disadvantages to TF panels. One is their lower power output per area. I have TF panels and they occupy about twice the roof real estate the MC would occupy for the same output.

Second, TF panels cost about twice the price of MC panels for a given output. My 64 watt panels cost about $350 each whereas a 120 watt MC panel would cost about $550. These are old prices, all have gone up considerably but the same ratio of costs remains.

Next: Mounting the Panels.
_________________________
...........From Nomad.........Been "on the road" since '97