You’ve learned how solar panel installation works and how to choose a reliable installer in Coimbatore. Now comes the final piece: avoiding the critical mistakes that destroy 20-30% of solar investments.
This isn’t theoretical. These are the exact errors I’ve seen ruin systems underperforming panels, fire hazards, warranty disputes, and thousands in wasted rupees. Homeowners call me frustrated after paying ₹2 lakh for systems generating half the promised power.
The good news?
Every single mistake below is preventable.
When you know what to watch for, you ensure your solar investment delivers the full ₹3,000+ monthly savings you expect. Let’s protect your investment.
Mistake #1: Wrong Panel Orientation & Tilt Angle
This kills 15-25% of your generation immediately.
The Problem: Panels facing east/west instead of true south. Tilt angles are too steep or too flat.
Coimbatore Reality: Optimal tilt = 11-12° south-facing. East-west orientation loses ₹15,000-25,000 annually.
What Happens: Your 3kW system generates 3,200 kWh instead of 4,500 kWh yearly. Payback jumps from 4 years to 6 years.
How to Prevent:
- Demand azimuth reading (true south = 180°) during site assessment
- Verify tilt angle matches latitude (Coimbatore = 11°)
- Ask installer for sun path diagram showing seasonal optimization
- Never accept “close enough” precision matters
Red Flag: Installer guesses orientation without compass or solar path analysis.
Mistake #2: Undersized Electrical Components
The silent killer of inverters and warranties.
The Problem: Using thin DC cables, undersized inverters, or skipping surge protection.
Real Consequences:
- Fire risk from overheated cables (happens in 8% of budget installations)
- Inverter failure within 2 years from voltage drops
- 15% generation loss from cable resistance
Coimbatore Fix:
- DC Cables: 6sqmm minimum (4sqmm = disaster)
- Inverter: Match AC/DC ratio to panel capacity exactly
- Surge Protection: Mandatory for monsoon lightning
- Earthing: 3-point minimum with 16sqmm copper
What to Check: Proposal must specify exact cable sizes, inverter model, and surge protection devices.
Mistake #3: Poor Panel Layout & Cleaning Access
Coimbatore’s dust destroys efficiency without proper planning.
The Problem: Panels installed edge-to-edge with no walkways. Impossible to clean.
The Impact:
- 2.5% monthly efficiency loss from dust accumulation
- ₹12,000 annual revenue loss for 3kW system
- Panels overheat when dust blocks airflow
Correct Layout:
- Panel rows: 60cm gap minimum
- Walkways: Every 3rd row
- Ventilation: 15cm air gap under panels
- Access ladders: Permanent mounting points
Prevention: Ask the installer to show layout drawing with cleaning paths marked. Real professionals plan for maintenance.
Mistake #4: Skipping Professional Roof Assessment
Your biggest structural risk.
The Problem: Installers assume your roof can handle 15-20kg/sq.m without checking.
Real Dangers:
- Roof leaks from improper mounting penetration
- Structural collapse risk on older homes
- ₹50,000+ repair costs when mounting fails
What Professional Assessment Includes:
- Load test calculations (IS 875 standards)
- Roof membrane evaluation (waterproofing condition)
- Wind load analysis (Coimbatore = Zone II)
- Penetration plan with sealing details
Red Flag: “No problem, all roofs handle solar.” Run.
Mistake #5: No Generation Guarantee or Commissioning
Paying for promises, not performance.
The Problem: System installed but never tested against projections.
Critical Commissioning Steps:
- Day 1: Measure actual vs. expected output
- Day 7: Verify net metering functionality
- Day 30: First month performance audit
- 90 Days: Full system health check
Demand This Document:
- Expected: 4,500 kWh/year
- Actual Month 1: 375 kWh
- Performance Ratio: 82%
Result: 10% underperformance = installer fixes free.
Mistake #6: Cheap Mounting Structures
The hidden failure point.
The Problem: Using mild steel instead of GI/Aluminum. Galvanization fails in 2-3 years.
Coimbatore Reality:
- Monsoon corrosion eats unprotected steel
- Heat expansion cracks poor welds
- ₹25,000 replacement cost after 5 years
Specify This:
- Material: Hot-dip galvanized MS or Aluminum
- Thickness: 2.5mm minimum
- Anodizing: Salt spray tested 1000+ hours
- Anti-corrosion bolts: SS304 grade
Mistake #7: Ignoring Net Metering & Approvals
Legal and financial disaster.
The Problem: Installation before TANGEDCO approvals.
Consequences:
- No subsidy (₹78,000 loss)
- No net metering (can’t sell excess power)
- Fines for unauthorized generation
- Insurance denial for accidents
Timeline Installers Must Follow:
- Week 1: File net metering application
- Week 4: TANGEDCO inspection approval
- Week 6: Bi-directional meter installation
- Week 8: Commissioning & subsidy release
Mistake #8: No Maintenance Plan
Solar isn’t “set and forget.”
Coimbatore Requirements:
- Monthly: Panel cleaning (dust critical)
- Quarterly: Inverter health check
- Annually: String performance audit
- 5 Years: Mounting inspection
Budget This: ₹3,000/year prevents ₹30,000 repairs.
Read more about this also – A Complete Guide to Solar Installation Costs by Popular Providers in India
The Perfect Installation Checklist
Print this for your installer:
- South-facing orientation verified (azimuth 180°)
- Tilt angle = 11-12° confirmed
- 6sqmm DC cables specified
- Surge protection included
- 60cm panel row gaps for cleaning
- Roof load calculation provided
- First-year generation guarantee
- 25/10/5 year warranties documented
- TANGEDCO net metering approval filed
- Commissioning report promised
Your Investment Protection Plan
One oversight = ₹50,000+ losses. Perfect execution = ₹7.5 lakh lifetime profits.
3kW Coimbatore System Reality:
- Year 1 Savings: ₹36,000
- 25-Year Total: ₹7.5 lakh (after costs)
- Payback: 4.2 years
- ROI: 28% annually
Perfect installation = guaranteed results.
Sloppy work = frustration and repair bills. Get this checklist signed before work begins. Hold installers accountable. Your financial freedom depends on execution quality, not panel brand.