DIY Solar Part 3: System Components

In our previous posts we talked about the design process and then different kinds of systems to choose from.Now let’s talk about the system components that you need to be aware ofbefore tackling a project like this. Many people believe that you justget some panels and wire them into the electrical system. It’s notquite that simple.

grid+tie+diagram DIY Solar Part 3: System Components


Solar Panels and FilmOf course the most obvious part of the system is the panel. But there are several types of panels to consider.

  • Crystalline panels: these are the blue-ish black solar panelsthat are encased in aluminum and tempered glass to protect them fromweather. These are the most common panels and generally the easiest tofind. Their advantage is that they can be mounted to nearly any surfaceand they have the highest efficiency.
  • Solar film:these cells look more like rolls of roofing materials than photovoltaicmaterials. This is probably the future of solar as these are muchcheaper to produce. Currently the only solar film that isavailable hasto be stuck to a metal roof. This will definitely change in the comingmonths and years as this technology advances.


Inverters
Solarpower makes direct current, or DC power, and your home uses alternatingcurrent, or AC, power. An inverter can turn steady stream DC power intowavy AC power. There are several different kinds of inverters and theydiffer in the kind of wave they create.

  • Modified sine waveinverters: create current that resembles connected up and down staircases, as the inverter creates steps in the current.
  • Pure sine wave inverters: these inverters create a nice even up and down sine wave.
  • Micro inverters:this is a new development where each panel has its own inverter. Thishelps in several ways. First it means that you can have a far smallersystem to start with since you could wire one panel and one microinverter and tie into the grid. All other grid-tie inverters require ahigher voltage and need at least 1000 watts (or 4 to 8 panels) to workproperly. Secondly inverting at the panel means you can use small gaugewire (instead of large diameter wire that DC requires) from the panelto the main power panel, saving money on wire cost.

Sensitiveelectronics, like entertainment equipment, require a pure wave tooperate properly, while smaller electronics, like small kitchenappliances, work just fine with modified wave. Pure sine wave is moreexpensive but it recommended since we have so many advanced-technologyelectronics in the home these days like computers, plasma televisions,and stereo equipment.

Charge Controllers
Wheneverbatteries are present in a solar power system, a charge controller isneeded. Most grid-tied system won’t have batteries and therefore won’thave a charge controller. Controller’s are needed because, unlike otherpower sources that have an off and on switch, solar panels are prettymuch ‘on’ as long as the sun is shining. This can be a problem if thebatteries are at full capacity as overcharging them would ruin them. Sothe charge controller controls how much charge goes into the batteries.

battery+and+grid+system DIY Solar Part 3: System Components

A typical battery-backup grid tie system.

Mostcontrollers are now Multi-Point Power Tracking, or MPPT, units. This afancy way of saying that the controller optimizes the amperage andvoltage in the system to recover the maximum wattage. This is becominga standard feature and you should not consider a non-MPPT controller.

Control Panels, Disconnects, and Wiring
Thereare a lot of fuse panels, disconnect switches, and wiring in a solarpower system. These are mixed and matched to suit a particular solarpower system. Usually there is a disconnect between each component. Thewiring can get expensive, so the distances between components should beminimized. DC power runs most efficiently through thick, heavy gaugewire, much like water flows better through larger pipe. The bigger thewire, obviously, the more expensive. So keeping your panels andinverters

Next week we’ll talk about system and component costs.

Kriss Bergethon is a writer and solar expert from Colorado.