Maximizing Solar Panel Efficiency: Key Considerations
Optimal Placement
Solar panels produce the most power when they face directly toward the sun. In South Africa, most residential solar systems are mounted on north-facing rooftops to maximize sunlight exposure. When evaluating your solar installation site, ensure it provides direct sun exposure by checking for potential obstructions like trees, chimneys, or other structures that could cast shade.
Shade Management
While photovoltaic (PV) optimizers and microinverters can improve performance in moderate shade, excessive shading will significantly reduce system output. Keep in mind that shadows lengthen during winter months, so even if your panels receive adequate sun in summer, winter shadows may impact performance.
Understanding Sun Hours
“Sun hours” refer to the time during which sunlight is strong enough to generate 1,000 watts per square meter. On average, locations receive 4–6 usable sun hours daily. The more sun hours your area gets, the fewer panels you’ll need to achieve your energy goals.
Determining System Size
The number of panels required depends on:
- Panel Efficiency – How effectively each panel converts sunlight into energy.
- Energy Goals – Your desired power output.
- Budget – The amount you’re willing to invest. See quotes
Grounding and Safety
Proper grounding of metal and electrically conductive materials is crucial to avoid electrocution and fire risks. Follow these key grounding guidelines:
- Ground solar racking according to the manufacturer’s instructions.
- Use permanent crimps for splices in grounding conductors, avoiding wire nuts.
- Connect the equipment grounding conductor (EGC) to the grounding busbar and extend it to the ground rod if possible.
Roof Condition and Longevity
Solar power systems are built to last over 25 years. Before installation, assess whether your roof is structurally sound to support the solar array throughout its lifespan.
Sizing Your Solar and Battery System
To properly size a solar and battery system, follow this formula:
Annual usage + 20% buffer = Daily usage x (70% for batteries + 30% for daytime use)
Imagine a house using 10,000 kWh of energy per year. Here’s how to calculate the solar and battery requirements:
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Add a Safety Buffer
Account for unexpected energy consumption growth and system inefficiencies by adding a 20% buffer to your annual usage. This increases the total to 12,000 kWh. -
Calculate Daily Usage
Divide the adjusted annual usage (12,000 kWh) by 365 days to determine daily energy needs. This gives an average of 32 kWh per day. -
Understand Energy Patterns
Since most energy is consumed during peak hours (4 PM to 9 PM), estimate that 70% of daily energy (23 kWh) will need to come from batteries for evening and nighttime use. -
Determine Solar Panel Requirements
To cover the total daily energy needs (32 kWh) and charge the batteries, size the solar array accordingly. With 5.5 sun hours per day, a 6 kW AC system should suffice. This system generates about 32 kWh daily (6 kW x 5.5 hours). -
Choose Battery Capacity
Opt for a battery bank that can store around 23 kWh of energy, ensuring sufficient power for non-solar hours and peak consumption times.