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FAQ

Most frequent questions and answers

Whether you should install rooftop solar or not depends upon a lot of factors, none more so than whether you have a free rooftop with enough space and shadow-free area. Post that it depends on what kind of electricity bills you are generating and what kind of power backup you have. In short this can be a little daunting. This is where Greenon Energy has as come up with a really interesting tool the “Solcal”. It is a solar calculator which requires very simple inputs and helps you know your solarisation potential. Using the more advanced version, you can further design the system and also personalise it. Should you need more assistance ask for a call-back or request a site survey.

Installing a rooftop solar PV system is any day a wise choice. It will help you to reduce your monthly electricity bill. But going completely off power from the grid might not be the best thing to do.

A grid-tied solution with net- metering is perhaps a better choice. You can enjoy all electricity generated by panel during day time and during night time, you can take power from grid. The math therefore is simple. A system with storage or an off-grid system requires a higher outlay of money owing to the batteries. For complete autonomy an even higher one! Whereas, with a Grid-tied or an On-grid system you have a choice of power sources your own Solar Power Generation System or the Grid. If you consume more than you generate, you pay for the excess units. On other hand, if you generate more than you “consume” then you get paid for the excess units.

An On-grid solar power generation system with 5 kW capacity would typically cost between Rs. 70/watt to Rs. 80/watt depending on the brands you choose, the balance of system inclusions and the quality of workmanship. Let’s say you consume 1,000 units monthly and your 5 kW system generates about 650 units per month, then your bill will be 350 units only. The Return on Investment is in around 4.5 years. Then you earn for a minimum of 20 years.

Choose an On-Grid solar power system. These systems are designed to work in conjunction with
the grid or simply put your electricity supply. The electricity you generate using this system is fed back to the grid. A net meter is installed along with this system to keep track of the electricity consumed by you versus what you generated and fed back to the grid resulting in savings which gets reflected in the bill. But keep in mind that it does not work when the grid is down, so if power back up is your objective, go for an off-grid solar solution.

Go for Off-grid solar power systems. These systems store the electricity produced by conversion
in batteries and utilise the stored energy by converting it back to AC so that you can keep running you appliances during power cuts. It’s a boon if you are living or planning to live in an area with no mains connectivity. The rising cost of other power sources as well as of and the increasing demand of electricity, especially in high power cut or no grid areas, has resulted in increased demand for such systems. The reduction in battery prices over the years has further brought the system cost down. But if you don’t have a power cut issue, then we suggest you go for an on-grid system as it will help you save big on your electricity bill.

A solar panel comprise of multiple PV (photo voltaic) cells that convert sunshine to electricity.
Two types of PV Panels are there – while one comprise of ‘Polycrystalline Cells”, the other one contains “Monocrystalline Cells” Polycrystalline cells are effectively a slice cut from a block of silicon, consisting of a large number of crystals. They have a speckled reflective appearance and are very thick. They are less expensive to produce and more suited for Indian conditions. Monocrystalline cells are much thinner and have a smoother feel to them. They are costlier to produce as compared to its polycrystalline counterpart. Based on the area available for solar installation, the required capacity of solar panels can be calculated. Call our solar expert to know your solar potential and get your solar journey started.

There are broadly two types of rooftop systems that you will hear about -On-Grid solar power system – These systems are designed to work in conjunction with the grid or simply put your electricity supply. The electricity you generate using this system is fed back to the grid. A net meter is installed along with this system to keep track of the electricity consumed by you versus what you generated and fed back to the grid resulting in savings which gets reflected in the bill. It does not work when the grid is down. Off-grid solar power system – These systems store the electricity produced by conversion in batteries and utilise the stored energy by converting it back to AC as and when required. The rising cost of other power sources and the increasing demand of electricity, especially in high power cut or no grid areas, has resulted in increased demand for such systems. The reduction in battery prices over the years has further brought the system cost down.

The most crucial component of a residential solar power plant is an inverter. It acts as an
interface which converts power produced by solar panels into electricity which can be
consumed to appliances. The type of inverter being used depends on the kind of solar power
system you are going for. Grid tie solar power systems need high efficiency power inverters for
optimising the performance. Another kind of high efficiency solar inverters are there for the off
grid solar power system that can charge batteries both from solar and grid power. The inbuilt
MPPT (Maximum Power Point Tracking) charge controllers in some good quality inverters
extract up to 30% more power from solar panels.

It is the most critical part as it acts as the skeleton for the entire system, a sturdy structure will
result in years of power generation as it need to withstand strong winds and other natural
forces. The type and orientation of the structure varies to a great degree depending on multiple
factors associated with the location where the solar power system needs to be deployed. The
structure for rooftop solar installation on a flat roof is completely different than that for a
slanted roof. The height of your roof is another major factor which determines the composition
and alignment of the structure. The quality of the material used has to be as per the MNRE
(ministry of new and renewable energy) specified norms. The structure needs is mostly made of
galvanised iron, which is not only stronger than normal iron but rust proof as well making the
solar power system last long.

You can’t use any regular cable for your solar power system. Specialised cables custom made for
residential solar power plants are used to ensure minimal loss of electricity being generated.
They are UV protected and strong and long lasting enough to withstand the rigours of nature –
be it peek of summers, incessant rains or thunder storms. Use of any ordinary cable is a big
health hazard as well with high chances of electrocution for the people in vicinity of the system.
Bad quality wire will not only make you solar power system in effective but will result being
more expensive as you will end up changing the wires of the entire system in the exposed parts
get deteriorated resulting in the risk of electrocution.

If you are going for an off grid solar solution, solar batteries are one of the crucial components as
they allow you to store the electricity generated by the solar plant and use it in case of power
outages or in case of no mains. A good battery would be the one which gives long back up and
requires very less maintenance (less frequent water to up).

These are the elements which are essential for proper functioning and safety of the system. No
compromise must be made on their quality or it will jeopardise the entire solar power system. In
terms of their functioning, while Junction Boxes are used to conceal the wiring connections all
across the system, Conduits on the other hand are used to protect the wiring of the solar power
plants, they can be rigid or flexible or a mix of both based on the requirement. Lightning
Arrestors are deployed to save the entire set up in case of a lightning strike, especially during
monsoon while Earthing, which is a grounding system connecting the residential solar power
plant to earth, is done in order to give passage to excess electricity during the lightning strike
and safeguarding the entire system in the process.

The installation of the solar power system needs to be done with precision in order to generate
maximum electricity through the solar power plant. No two roof-tops are the same therefore
the process requires system design and careful supervision to ensure proper installation of the
solar rooftop power plant. Solar panels used in any solar power system should be installed
facing South direction. Tilt angle of solar panel should be around 30% in India, but it varies as
per the height of the installation. Solar panels must be grouted using anchor bolts or concrete
foundation to ensure durability in rough conditions. UPS and batteries must be installed as close
to the panels as possible to minimize DC transmission losses. One needs to ensure that the
maximum permissible voltage is not exceeded when connecting the panels in series. There
should be a minimum gap of 5 mm between two solar panels to allow for any expansion in
materials. The solar panels being interconnected must be of the same type (mono or poly) and
same power class. There should be no shade or shadow on the solar panels as this may lead to
losses, formation of hotspots etc.

The performance of solar (PV) panels is affected by the shading effect of surrounding trees and
buildings, passing clouds basically anything that casts a shadow on to the panels. The sun light
converted into energy by the PV panels shall depend on the amount and duration of the shadow
falling on it. Lesser the shadow, more the energy! No shadow – maximum energy!

Solar panels need to face true south direction for maximum power generation. The reason
behind it is that when sun moves from east and goes to west, it leans towards south direction.
Irrespective of which part of year it is, inclination will always be towards south. Hence for the
optimum harnessing of sunlight, the solar PV panels should ideally face south.

The angle at which the solar panels are fixed according to your location’s latitude. In general, the angle of tilt will lie between 10 to 20 degrees in India. The angle decreases as the altitude of installation increases to nullify the impact of high speed winds on the installation.

Worried about solar panels warranty? Don’t worry, as the panel’s come loaded with 25 years of performance warranty!

India is a country where dust tends to accumulate very quickly on the panels hampering there
optimum generation. Solar Panels have to be cleaned at least twice every week, would be great if you can manage to do it daily, to make the most of the sun rays falling on it. It is recommended to do it using a wipe after a strong water spray.

A solar rooftop power system will deliver the full return on investment only if runs as smoothly
as possible. This means periodic inspections of the individual components of the system. A
timely intervention can prevent the threat of diminished output or downtime or a safety hazard.
This why it’s important to get in touch with a reputed brand to install your solar system so that
all this can be taken care off. Click here to find out how.

In case of rooftop Grid-Tie solar power system, one must ensure that all the necessary govt. requirements for getting net-meter installed are being taken care of. This may require additional time and fees depending on the local electricity utility. For battery based systems, no permits are required. However, in case there are subsidy schemes offered by local government, additional documentation may be required for subsidy. Greenon Energy products are designed as per IEC standards, and are eligible for subsidy schemes. Ministry of New and Renewable Energy (MNRE) regularly announces subsidy and its disbursement procedure on its website, it’s recommended to visit the same.

No, it even works when it’s cloudy! Obviously the power generation will not be optimal but it does not stop working. Also, with 300 sunny days, India is blessed to be the best destination for solar power generation.

It’s suitable for all type of buildings. The only prerogative is that there should be a roof on top of it, strong enough to support the structure. Installation also varies depending on whether the roof is slanted or flat. In India, we mostly have flat roofs and the structures are created accordingly. The position of the surrounding elements, such as buildings or trees, which can cause shade on the panels play a crucial role in determining the area on the roof suitable for optimum solar power generation. At times there are obstacles on the roof, such as water tanks, which affects how the structure to support the solar panels will be erected as well.

Sure thing! One just needs to make the calculations correctly in terms of what all appliances are being run on solar. Power requirement of a water pump generally lies between 250 to 1100 watts. Just make sure that the total accumulated load does not exceed what is being generated by the solar panels. It also depends on what type of system do you have. If you have an on-grid system, you can use the solar power during the day part by directly connecting the water pump load to the solar set up. In case of an off-grid system, you can use the energy stored in the batteries to run your water pump any time during the day. The duration of usage will depend on the capacity of the batteries and the level of their charging.

The most crucial part of maintaining a solar power system and making sure of the optimum power generation is to keep the solar panels clean. Ideally, it should be done at least twice a week. If you can do it daily, nothing like it. Apart from this, all the main components come with performance warranties, so you don’t have to worry about the other stuff too much. Solar panels come with 25 years of performance warranty while that of inverters and batteries keeps on varying.

The Return on Investment takes place in around 4.5 years. Then you earn for a minimum of 20 years. Not only you generate your own electricity, you also help reduce the carbon footprint contributing to a healthier environment and making money in terms of savings either due to reduced electricity bill (if you are using an on-grid solar system) or reduction in diesel cost (if you are using an off-grid solar system).

Absolutely, In case of rooftop Grid-Tie solar power system, the owner must complete all the
necessary requirements for getting net-meter installed. This may require additional time and fees depending on the local electricity utility. Any good service provider will assist you fully in the process. For battery based systems, no permits are required. However, in case there are subsidy schemes offered by local government, additional documentation may be required for subsidy. Greenon Energy products are designed as per IEC standards, and are eligible for subsidy schemes. Ministry of New and Renewable Energy (MNRE) announces subsidy and its disbursement procedure on its website regularly, you may pay them a visit as well to know more.

The best way to do it is to call a professional to help you out as there are many aspects and methodologies which needs to be taken into account before one arrives at the recommended system size for a particular site. Therefor it is advised to book a site survey with us and let our solar expert inspect your roof to suggest the best possible solution for you.

With a multitude of solar installers available, defining the parameters for choosing the right one is a tough decision. Even though price seems to be the sole lucrative parameter, industry experts wouldn’t suggest the same. Right from solar panels, inverters to the services offered by your installer like mounting the structure and other necessary civil work, everything has to be seamless. This is where a brand scores over the local installers.While it is a pain to pay a little extra, but this solar system is going to last you for more than 25 years. So it is perfectly fine to bear that extra cost for warranty benefits and any assistance you might need in the future. Look for companies that have been around for a long time and use branded products, you don’t want to end up probing for the original manufacturers to avail that warranty clause. If you choose to go ahead with a brand, you won’t get the surprise of hidden costs in the middle of the project as there will be complete transparency, you will get efficient rooftop panel design ensuring maximum generation and there will be no compromise when it comes to your safety.

Installing a rooftop solar PV system is any day a wise choice. It will help you to reduce your monthly electricity bill. But going completely off power from the grid might not be the best thing to do. Why? If you completely cut-off from grid, then you will be needing batteries for storing the light energy that is converted into electricity. This energy then shall be re-converted for use and it is here that efficiencies of conversion come into play. Also batteries increase cost as they need to be replaced every 4-5 years and require maintenance. A grid-tied solution with net-metering is perhaps a better choice. You can enjoy all electricity generated by panel during day time and during night time, you can take power from grid. The math therefore is simple. A system with storage or an off-grid system requires a higher outlay of money owing to the batteries. For complete autonomy an even higher one! Whereas, with a Grid-tied or an On-grid system you have a choice of power sources your own Solar Power Generation System or the Grid. If you consume more than you generate, you pay for the excess units. On other hand, if you generate more than you consume then you get paid for the excess units.

FAQ

Product Specific

The electricity bill you save is proportional to the capacity of the solar panel installed. In tropical country like India, we can expect average 4-5 hours of good sunlight for about 300 days in a year. A 1000Wp panel, will generate about 4-5 units per day on a sunny day.

Installation by a trained technician is very important. There are many details like the quality of input & output wiring, reverse supply of AC voltage on the output, proper safety Earth, polarity of wiring, routing and casing of the PV cable etc. which has to be done as per standards. Ease of maintenance in case of a breakdown is also an important consideration. Good installation ensures trouble free and long life. Hence, get installed only by a trained technician.

PV systems are currently considered to have at least a 25 years lifespan. PV modules are covered with a long term performance guarantee (usually 10 years with less than 10% decrease and 20 years with less than 20%) by all the most important manufacturers. Guarantees for electronic components such as UPS can also be extended for several years beyond standard terms.

For savings on electricity bill there are On-Grid System or Grid-tied System. These systems are designed to work in conjunction with the grid or simply put your electricity supply. These systems depend on the reference voltage provided by the grid for their operations and do not work when the grid is down. Thus, it is a combination of solar PV and the grid.

The electricity bill you save is proportional to the capacity of the solar panel installed. In tropical country like India, we can expect average 4-5 hours of good sunlight for about 300 days in a year. A 1000Wp panel, will generate about 4-5 units per day on a sunny day.

It depends on the extent of power you want to generate. Make a list of the total load and the time it will be ON in a day. Multiply individual load by the time it operates in a day to get the energy consumption (Watt-Hour) per day. Divide this figure total by 4 (Sun hours). This figure gives the approximate total panel Watts.

The PCU supports mono or poly-crystalline panels. For 12V battery system, 36 cell panels with VOC about 21V should be used. Usually 36 cell panels are below 140Wp. Hence for higher capacity, many panels should be connected in parallel. In the case of 24V battery system, 60 or 72 cell panels can be connected. These have VOC about 36V and 42V respectively. It is allowed to connect two 36 cell panels in series to make it suitable for 24V system. You should not connect 60 or 72 cell panel to a 12V battery system.

The SOLAR mode is the power generation mode. This mode is to be selected in places where grid power is stable and available. The objective is to reduce the dependence on grid power. When the day starts, the PCU first charges the battery. Once the battery has charged, it then disconnects the load from grid and connects to the UPS. Simultaneously, the Solar Panel will be charging the battery and so the load runs on Solar Power. In the evening when the sun sets, the UPS continues to supply the load from the battery. This continues till the battery reach reserve level after which the load returns back to grid supply. It continues in grid till next day morning and then the solar charging takes over. Grid charging will happen only if the battery has gone below reserve.

In a PCU, the load is automatically changed to UPS and grid depending on its operation. Hence, if excess load is installed in grid mode, then when it goes to UPS, it may trip in overload. It is recommended that only the loads that normally runs in the UPS mode is connected to the system.

As there are certain specifications you should use when evaluating your solar battery options, such as how long the solar battery will last or how much power it can provide. Below, learn about all of the criteria that you should use to compare your home energy storage options, as well as the different types of solar batteries.

The PCU has a fully automated & complex charging algorithm using Constant Current-Constant Voltage (CC-CV) method. Since in the solar mode frequent charge-discharge happens, to ensure good health of the battery automatic equalize charging is done every 30 days. Hence no external charging is required.

Installation by a trained technician is very important. There are many details like the quality of input & output wiring, reverse supply of AC voltage on the output, proper safety Earth, polarity of wiring, routing and casing of the PV cable etc. which has to be done as per standards. Ease of maintenance in case of a breakdown is also an important consideration. Good installation ensures trouble free and long life. Hence, get installed only by a trained technician from a good company.

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