Rising electricity bills has caused electricity consumers to look for other energy options. Since, vast portion of India comes under the tropical region availability of sun is good throughout year. Tamil Nadu is southernmost state which is situated at the seashore of Indian Ocean, Arabian Sea & the Bay of Bengal. Tamilnadu is having average solar irradiance of more than 5 kWh/m2/day which is considered best for solar electricity generation.
Why Off-Grid/Hybrid solar rooftop systems ?
Basically there are two types of solar rooftop system & those are (1) On Grid (2) Off-Grid solar rooftop system. Both are crucial for reducing the electric bills but Off-Grid solar rooftop systems offers backup even when grid supply (Distribution company supply) is not available. To run the on-grid inverter distribution company supply is required.
Since, the state of Tamil Nadu is surrounded by the oceans & hence cyclones and floods are the regular phenomenon of rainy season. Cyclones and floods causes breakdown of electricity. Sometimes, citizens faced no supply of electricity even for the days. Hence, on-grid consumer may face shutdown or no electric supply even during the day.
Hence, to overcome the problem on-grid solar rooftop system, off-grid solar rooftop system is recommended specially for the citizens residing in coastal areas.
Understanding Off-Grid solar rooftop system-
Basic difference between on-grid and off-grid solar rooftop is the inverter and batteries. Off-grid solar rooftop system uses the off-grid inverter and batteries. Capacity of the inverter is decided by the battery voltage and inverter starts only when required number of batteries are connected.
Off-grid inverter differs from the on-grid inverter in a sense that it can handle the electrical load limited to it's rating. Consider a case of 1 kVA inverter, if one has installed 1 kVA on-grid inverter he can put the load of 2 kVA, 3 kVA but that is not the case with off-grid inverter. Off-grid inverters can handle the load less than the rated capacity of the inverter e.g., 1 kVA off-grid inverter can handle the load of less than or equal 1kVA.
Some inductive loads such as Air Conditioner, Geyser, Washing Machine, Refrigerator requires 3-4 times the rated current to start & after that they settle at rated current. To meet the initial starting current requirement of inductive loads, our inverter rating must be on higher side else that equipment won't start.
Hence, one must calculate the actual electrical load of his installation before purchasing the off-grid solar rooftop system or contact us at help@apollouniverse.com.
Selection of solar panels-
After deciding the capacity of off-grid solar inverter, capacity & type of solar panels is the important aspect for solar off grid rooftop system. Solar panels can be categorized based upon the technology - (1) Poly-Crystalline (2) Mono-Crystalline (3) Half Cut Mono-Crystalline (4) Bi-Facial Half Cut Mono-Crystalline. Among these Bi-Facial Half Cut Mono-Crystalline & Half-Cut Mono-Crystalline offers efficiency of close to 21% which is approximately 30% higher than Poly-Crystalline solar panels. One can select the solar panel based on availability of space, sunrays etc.,
Off-grid solar rooftop system prices-
1) Prices for Loom Solar Mono-Crystalline Panels, Waaree Energies PWM Inverter & Luminous 150 Ah, Solar C-10 battery including installation cost-
| Capacity (kW) | Solar Inverter |
Battery (150 Ah) |
Suitable for Load | Estimated Monthly Savings Units/Month | Price (Rs) |
|
o.5 |
1050 vA |
1 Nos |
Light-6, Fan-2, Refrigerator-1 |
50-70 |
49,000 |
|
1 kW |
2750 vA |
2 Nos |
Light-8, Fan-2, Refrigerator-1 |
100-120 |
89,000 |
|
1.8 kW |
2750 vA |
2 Nos |
Light-10, Fan-4, Refrigerator-1, Washing Machine-1, Computer-1 |
180-220 |
1,05,000 |
|
2.8 kW |
3750 vA |
4 Nos |
Light-10, Fan-4, Refrigerator-1, Washing Machine-1, Computer-1, AC (1 T) -1 Nos |
280-300 |
1,65,000 |
|
3.6 kW |
5500 vA |
4 Nos |
Light-12, Fan-4, Refrigerator-1, Washing Machine-1, Computer-2, AC (1.5 T) -1 Nos, Geyser (3 kW) -1 |
380-450 |
2,75,000 |
|
5.3 kW |
7500 vA |
10 Nos |
Light-20, Fan-8, Refrigerator-1, Washing Machine-1, Computer-4, AC (1.5 T) -2 Nos, Geyser (3 kW) -1 |
500-650 |
3,49,000 |
(Note- Load indicated is for reference purpose only.)
2) Prices for Loom Solar Mono-Crystalline Panels, Waaree Energies PWM Inverter & Autobat LiFePo4 battery (120 Ah) including installation cost-
| Capacity | Inverter | Battery Voltage | Suitable Load | Estimated Monthly Savings Units/Month | Price |
| 0.54 kW | 1050 vA | 13.2 Volts | Light-6, Fan-2, Refrigerator-1 | 60-80 | 59,000 |
| 1 kW | 2750 vA | 26.4 Volts | Light-8, Fan-2, Refrigerator-1 | 110-150 | 1,10,000 |
| 1.8 kW | 2750 vA | 26.4 Volts | Light-10, Fan-4, Refrigerator-1, Washing Machine-1, Computer-1 | 240-300 | 1,35,000 |