Residential Solar system: 9 things you should know before purchasing

Are you confused about whether you are installing a proper solar system or not? Do you want to check whether your installer is doing adequate work or not? Want to know some important things about solar before purchasing it? Here I will give you the answer which will help you to verify and get assurance that your money is utilized correctly. At last, I have given a summary of all, so don't miss that.

Here are the 9 things that you should check for a better outcome:‍

1. How much solar is required for you?

- This is a necessary step that you should first do before installing solar for your home. I am telling you a straightforward way we use in India to estimate this.

- List down the units consumed by you in the past 1 year. Take 2 maximum numbers from them and find the average amount. Now divide this number by 120, and you'll get the answer in decimal points.

- Take the upper limit of that number, considering that in the future your use of electricity will only increase.

For example, My 2 maximum units are 270 and 290, the average of that is 280. Now, 280/120 = 2.33 kW. This means that I will prefer to install 3 kW of the system at my home, not more than that.

2. Shadow analysis of your rooftop

- This is one of the crucial parts you as a customer have to understand. If there is a tree, Building or walls beside the area where you are planning to install the solar system, then you must wait for that.

- Ask your solar vendor to generate a shadow analysis report for your installation. Shadow analysis report guides you about the effect of shadow on your installation throughout the year. This will help you to identify the shadow-free area and thus install a solar system there.

- If there is even a little amount of shadow on any of the panels, the generated output might drastically decrease. So before installation, you must verify this with your vendor.

3. What is the fact about 25 years of warranty in a solar panel?

- Generally, when you talk to any solar vendor, they will tell you that we are using a panel with 25 years of warranty. But is it so? Let's find out.

- Solar panel manufacturers will state 2 warranties in their datasheet but market mostly the one. They give 25 years of output warranty meaning that the output power generation from the panel will remain within a specific limit in most cases 80% till the 25 years.

- After 1st year generally the efficiency will decrease by 2.5% and after that, till the 20th year, it will reduce by around 0.7-0.9%.

- The thing which you should know is you have 10 years of the product warranty on most solar panels. So for 10 years, if there will be any physical damage to the panel, the manufacturer will replace it.

- One significant thing here you as a client have to understand is that for this long term warranty you should always choose a manufacturing company which is atleast 7-10 years old in the market or has a good brand establishment in the market.

4. Is the angle of solar panels necessary?

- It is one of the most important things to consider because proper angle and direction can generate almost 1.5 times more output than a wrong angle and direction.

- First, if I talk about direction, India is in the Northern Hemisphere of the earth, so in India, the direction of solar panels should always be South facing. So that it can capture most out of the sunlight.

- Now let's talk about the tilt of the solar panel, the most essential thing that we have to implement is solar panels are tilted in the south direction with an angle equal to or within the range of Latitude of that location.

- Also, understand one thing that in winter the sun is lower than the normal position and in summer it is a little higher than the normal latitude position. So the outputs will also vary if you have installed a fixed solar panel angle. In India, generally, installers do the fixed type of installation only.

- But according to the study, it is given that if you can change your tilt angle of solar panels twice a year, then the overall output will increase by almost 5%.

- If the change in angle is not possible, then it is advised that your tilt angle should be equal to or 4% of the Latitude of the location.

5. Inverter warranty and sizing

- Usually, we ask for the warranty of panels from the vendor, and we consider this as a full system warranty. But Most of the Inverter gives only 5 years of the warranty period for any damage.

- We also have to verify that Inverters are of the same specification as of our system, or a little less is still okay. As 3.97 kW of, a system must have an Inverter of 4 kW and not of 3 kW.

6. Place of your Inverter

- Many of the household clients insist on their solar vendors that they want to install Inverters near their main Grid meter. So that they can see the daily production of panels and find any fault very easily. If you're also one of them, then you are wrong.

- As we know, solar panels produce DC current, and that will flow to the Inverter via DC cable. DC cable diameter is more than the AC cable diameter. The loss that occurs in the cable is directly related to the area and distance between the two terminals.

- So if the distance between the panel and Inverter is more, DC losses will be more.

7. Connection of Solar panels

- For any solar system, solar panels must be connected in a series connection. For a medium to a large system, all the series connections of panels (strings) should be connected in parallel to the Inverter.

- Series connection means the Negative of one panel will be connected to the positive of the next one.

8. Grounding of the system

‍There have to be 3 separate groundings for the solar system.

1. DC grounding to protect solar panels and structure

2. AC grounding to protect home appliances, Inverter, and main supply line

3. Lightning arrestor for protection of solar structure and panels in any natural skin Lightening condition.

9. Material of the structure used for installation

- In India, we prefer that the structure of a solar system should be of Hot deep Galvanized Iron. It is free and thus sustains for an extended period. The Thickness of the structure should be much more robust than it can withstand a heavy wind load.

Summary

1. Calculate the actual requirement of your solar system by electricity bills.

2. Do a Shadow analysis of your rooftop to know the Shadow-free area for installation.

3. Solar panels have 10 years of product warranty and 25 years of output warranty.

4. The tilt angle of solar panels should be equal to the Latitude of that location, which you can find on Google.

5. Inverters usually have 5 years of warranty and get the required kW size of Inverter.

6. The place of your Inverter should be near the solar panels to minimize losses.

7. Connection of Solar panels should be in Series with each other.

8. Three Groundings are a must for a residential solar system.

9. The material of the structure used for installation should be robust and rust-free, like Hot deep galvanized iron.

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