Why installation quality matters more than panel brand
A poorly installed 6 kW system will underperform a well-installed 4 kW system. Shading analysis, cable sizing, mounting angle, and inverter configuration account for 15–30% of real-world yield. Here are the most common mistakes to watch for.
Mistake 1: Ignoring shading
A single shaded panel in a string can reduce output of the entire string by 50–80% for hours. A good installer will use a shading analysis tool (SunEye or SolarEdge Designer) and either re-route the string layout or recommend microinverters / optimisers for partially shaded roofs. Ask your installer to show you the shading analysis.
Mistake 2: Undersizing the inverter
Homeowners sometimes save money by choosing a smaller inverter than the panel array warrants. This causes "clipping" — lost energy when the panels produce more than the inverter can handle. As a rule, your inverter should be rated at 80–100% of your total panel capacity.
Mistake 3: Wrong panel orientation
In South Africa, panels should face north for maximum annual yield. West-facing panels can work well for afternoon peak users but produce 15–20% less annually than north. East-facing panels are rarely optimal. Flat roof systems should be mounted at a minimum 10–15° tilt for self-cleaning and optimal yield.
Mistake 4: Undersized DC cabling
Thin DC cables between panels and inverter cause resistive losses. SANS 10142 specifies minimum cable sizes — ensure your installer uses 6mm² or larger for runs over 10m. Ask for the cable sizing calculation on your installation.
Mistake 5: Not checking inverter compatibility with battery
Not all inverters work with all batteries. Before purchasing, verify your chosen inverter and battery brand are on each other's compatibility list. Common mismatches: Victron + Pylontech (works), Deye + Hubble (verify firmware version), Growatt + generic lithium (varies).
Mistake 6: Skipping the COC
A Certificate of Compliance is required by law and by your insurer. Some cheaper installers skip it. Without a COC, your insurer can refuse to cover fire or electrical damage related to the installation — leaving you with no recourse.
Mistake 7: Using an unregistered installer
SAPVIA registration requires technical competency assessment and professional indemnity insurance. Unregistered installers have no accountability. Your SARS Section 12B rebate may also be disallowed if the installation isn't done by a qualified electrician.
All installers in the FlowLeads network are SAPVIA-registered and carry professional indemnity insurance. Get a free quote from a verified installer near you.