If you are considering solar installation for your home, it helps to know what you are putting on your roof. Solar panels look simple from the outside, but each one is a layered assembly of materials chosen for durability, conductivity, and weather resistance.
Understanding what goes into a solar panel also helps you compare products, ask better questions during quotes, and spot the difference between budget hardware and panels built to last 25 years on the Mid North Coast.
The Six Main Components of a Solar Panel
Every residential solar panel shares the same basic structure, from the glass on top to the junction box on the back. Here is a layer-by-layer breakdown.
- Tempered glass (front cover)
- EVA encapsulant (adhesive and sealant layers)
- Silicon photovoltaic cells (the power generators)
- Backsheet (rear protective layer)
- Aluminium frame (structural support)
- Junction box and wiring (electrical connections)
Each component plays a specific role in converting sunlight into electricity and protecting the panel from the elements.
Silicon Cells — Where Electricity Is Made
The photovoltaic (PV) cells are the core of every solar panel. Almost all residential panels use silicon, which is the second most abundant element in the Earth’s crust after oxygen. Silicon is a semiconductor, meaning it conducts electricity under the right conditions — specifically when photons from sunlight knock electrons loose from the silicon atoms.
There are two main types of silicon cells used in residential panels.
| Cell Type | How It Is Made | Efficiency | Appearance |
|---|---|---|---|
| Monocrystalline | Cut from a single silicon crystal ingot | 20 to 24% | Uniform dark black |
| Polycrystalline | Cast from melted silicon fragments | 15 to 18% | Speckled blue |
Monocrystalline cells dominate the Australian residential market. The single-crystal structure allows electrons to flow more freely, which is why mono panels are more efficient. Most panels you see quoted today use mono PERC (Passivated Emitter and Rear Cell) or the newer TOPCon technology.
Polycrystalline panels are still available but increasingly rare in residential quotes. The price difference between mono and poly has narrowed to the point where mono panels offer better value per watt.
How Silicon Cells Generate Power
Each cell has two layers of silicon doped with different elements. The top layer is doped with phosphorus, giving it extra electrons (negative charge). The bottom layer is doped with boron, creating gaps called holes (positive charge). When sunlight hits the cell, it knocks electrons loose, and the electric field between the two layers pushes them through an external circuit. That flow of electrons is electricity.
A standard residential panel contains 60 or 72 cells wired together in series. Half-cut cell designs (120 or 144 half-cells) are now common because they reduce resistive losses and improve performance in partial shade.
Tempered Glass — The Front Line of Defence
The glass layer on top of the panel is not ordinary window glass. It is tempered, meaning it has been heat-treated to be roughly four times stronger than regular glass. It needs to withstand hail, fallen branches, wind-blown debris, and decades of UV exposure.
- Thickness is typically 3.2mm for residential panels
- Anti-reflective coatings reduce light bounce and improve energy capture
- Low-iron glass lets more sunlight through than standard glass
- Some premium panels use textured glass to capture light from wider angles
On the Mid North Coast, salt spray and humidity are bigger concerns than snow load. Quality tempered glass with proper coatings resists corrosion and stays transparent for the life of the panel.
EVA Encapsulant — The Invisible Protector
Between the glass and the silicon cells, and again between the cells and the backsheet, sits a layer of ethylene-vinyl acetate (EVA). This clear polymer is laminated onto the cells under heat and pressure.
EVA serves three purposes.
- Adhesion: It bonds the glass, cells, and backsheet into a single solid unit
- Moisture barrier: It stops water from reaching the cells and electrical connections
- Shock absorption: It cushions the brittle silicon cells against vibration and impact
Cheap EVA yellows over time, reducing the amount of light reaching the cells. Quality manufacturers use UV-stabilised EVA or alternative encapsulants like POE (polyolefin elastomer), which resists yellowing and moisture ingress better in humid coastal climates.
Backsheet — Keeping Moisture Out
The backsheet is the white or black layer you see on the rear of the panel. It is usually made from a multi-layer polymer film, often based on PET (polyethylene terephthalate) or fluoropolymer materials like Tedlar.
- Protects electrical components from moisture, dust, and mechanical damage
- Provides electrical insulation to prevent short circuits
- White backsheets reflect heat and keep the panel cooler (better for efficiency)
- Black backsheets look sleeker but run slightly hotter
Backsheet failure is one of the main causes of premature panel degradation. Cracking, delamination, or moisture ingress through a cheap backsheet can short-circuit cells and void your warranty. This is one area where cutting costs on a budget panel can come back to bite you.
Aluminium Frame — Structure and Mounting
The aluminium frame surrounds the glass and backsheet assembly, giving the panel its rigidity and providing mounting points for your roof racking system.
- Anodised aluminium resists corrosion, which is critical in coastal areas like Port Macquarie
- The frame also seals the edges against water ingress
- Corner joints are the weak point — look for panels with reinforced corner keys
- Frameless panels exist but are mainly used in commercial ground-mount systems
A solid frame matters more than most people realise. It carries the wind load, supports the panel’s weight on the racking, and keeps the laminate sealed for 25 years of weather exposure.
Junction Box and Wiring — The Electrical Backbone
On the back of every panel is a small weatherproof box called the junction box. It houses the bypass diodes and the cable connections that link your panels together and feed power to your inverter.
- Bypass diodes: Route current around shaded or damaged cells so one weak spot does not kill the whole panel’s output
- Cables: Typically 4mm² or 6mm² copper wiring with MC4 connectors for secure, weatherproof connections
- IP rating: Quality junction boxes are rated IP67 or IP68, meaning they are sealed against dust and water immersion
Poor junction box sealing is another common failure point in cheap panels. Water inside the junction box causes arcing, corrosion, and potentially a fire risk. A CEC-accredited installer will check junction box quality as part of their assessment.
Choosing panels with quality components matters as much as choosing the right installer. Contact SolaXs for advice on which panels suit your home and budget.
How Materials Affect Longevity and Warranty
The materials inside your panels directly determine how long they last and how well they perform over time.
- Better silicon purity means slower degradation and higher output at year 25
- UV-stabilised EVA or POE encapsulant prevents yellowing in strong Australian sun
- Quality backsheets resist cracking in the heat cycles the Mid North Coast experiences
- Anodised aluminium frames hold up to salt air far better than untreated frames
When comparing quotes, look beyond the watt rating and price per panel. Ask about the bill of materials. A panel with a 25-year product warranty and a 25-year performance warranty is making a promise about its components, not just its lab test results.
Talk to Your Local Solar Team
SolaXs has been installing solar across the Mid North Coast for over 25 years. We only recommend panels with the build quality to handle coastal conditions, and we are CEC accredited to ensure every install meets Australian standards.
If you want to understand what is going on your roof before you sign a quote, get in touch. We are based in Port Macquarie and happy to walk you through the hardware in plain English.