The Guide to Off-Grid Solar Systems
An Off-Grid solar system is essentially a personal power plant. Unlike On-Grid systems that work like an "App" on the main grid, an Off-Grid system is the entire Operating System.
Core Components
- Solar Panels: To generate DC electricity during the day.
- Charge Controller (MPPT): To regulate voltage and charge batteries efficiently.
- Battery Bank: The "Tank" that stores energy for night use.
- Off-Grid Inverter: Converts stored DC power from batteries to 230V AC for appliances.
Sizing Advice: The "Autonomy" Factor
"Autonomy" refers to how long your system can run without sunlight.
- 0.5 Days (Night Only): This is standard for most users. You use solar directly during the day and batteries only at night.
- 2 Days (Monsoon Proof): If you live in an area with heavy rains (e.g. Konkan, Kerala), you need to oversize your battery bank to survive 2 days of cloudy weather.
Why is it expensive?
The cost per watt for Off-Grid is higher because you are buying Storage. In an On-Grid system, the Grid acts as your free infinite battery. Here, you have to buy the battery.
- On-Grid Cost: ~ ₹60/Watt
- Off-Grid Cost: ~ ₹90-100/Watt (depends on battery chemistry)
Maintenance
Lead Acid batteries require regular gravity checks and water topping. Dust on panels affects off-grid systems more severely because you don't have the grid as a backup. Regular cleaning is mandatory.