[sagarpadaki]

Originally Posted by graaja

You are right. The cost of structure would be 3x to 4x compared to the low lying structure due to the increased thickness. Also cleaning would become very difficult.

Excellent stuff graaja. The outcome is very neat and functional!

Might I suggest that you coat all the solar panels with ceramic coating. This will ensure that the dust and grime do not stick to the glass and thereby reduce the thermal efficiency. Easy to clean and will self clean during rains.

[thanixravindran]

Originally Posted by graaja

Solar Power for Irrigation and Electricity at Farm

Wow, Fantastic graaja. An Off-grid farm like 'Down under' is a dream that can be very rarely realized here. Congratulations and Best wishes.

I can only imagine the smile on your face when the first water was pumped out using solar energy. I had the same feeling when in 2018, I installed my small 1 KW Solar in my rooftop and powered my energy optimized home (My wife was laughing as if I am in a tribal village seeing electricity for the first time ). After this inspiration, I am now interested to go for Solar for my home borewell pump.

I have few questions

1. Is there any reason that you did not consider a single phase pump which I think is available in 230V range? Or in future you want to get the 'Mains' from Electricity board also? I presume you don't have any need for night irrigation which is mostly done when 'Mains' is available.

2. Since you have series connected all the panels, have you considered a scenario when one of the wires can be bitten say by a rat that can stop the entire solar system? (Apologies if this is coming in a wrong way, but since I was an product development engineer, my mind is trained for FMEA).

3. What is the overall DC connection length that is ongoing from the panels to your control room (which I think houses both VFD as well you home inverter)? I guess the poles carry 220V AC to your home from control room and are properly sized and insulated.

4. Did your installer do any full day survey for the sun or shade pattern from morning to evening prior to the installation?

5. Have you considered any insurance for this solar farm set-up? Is anything available?

Your set-up is excellent as per the good practice for the height. The steel-concrete structure at a height upto 3 feet even in roof top is generally rated for winds upto 220Km/hr. I did this research and consultation with Luminous given Chennai has experienced Vardha cyclone couple of years (2016) before my installation.

Please consider a system to wash the panels may be using the same Solar pump water with automation.

[frewper]

Excellent Thread as always Graaja. And what an excellect project to have.

Obvious I am too raising my hand for a few questions.

1. You mentioned you intend to use a PLC for controlling the values. I am assuming you have something else planned to add on the PLC? Since the cost of adding a PLC and programming it might not be cost effective. Even if we go in for the cheapest PLC.

Or do you plan to build it yourself? Then it would make sense.

2. Is cleaning the panels that difficult? Wouldnt just holding the water pipe directly from the pump clean the panels easily. Given its not too high.

3. Since there are no mains, are you planning to keep some small electric generator as a backup.

[fordday]

First, a big congratulations on your setup. I am sure it gives you immense pleasure when you see the sun's energy put to use on the farm. Hope it gives you a hassle free years of operation.

Originally Posted by graaja

The INVT variable frequency drive. The drive displays the frequency at which the pump is being run. The frequency varies anywhere between 10Hz to 45Hz based on the intensity of sun. The pump speed and hence the water output varies with this frequency.

I wanted to know what exactly is the function of the VFD? You mentioned it shows the frequency at which the motor is running. Doesn't a regular solar inverter creates/matches the normal 50Hz frequency?

[aim120]

Originally Posted by fordday

I wanted to know what exactly is the function of the VFD? You mentioned it shows the frequency at which the motor is running. Doesn't a regular solar inverter creates/matches the normal 50Hz frequency?

The pump he is using is a 3 phase motor, which means with a VFD (variable frequency drive) one can control the rpm of the motor by varying the frequency. This way you have no inrush current during start up, can change the rpm when one requires lower pumping or lower power consumption.
A regular inverter takes DC from the solar panels and converts it to AC 50Hz single or three phase.

His VFD takes the solar DC and converts it to 3 phase AC but with variable frequency (user controlled).

If he had just used a regular solar inverter, he would have needed a 3 phase solar inverter which costs about 2lakh or more. Further more running the pump with 50hz fixed frequency would result in a high inrush current, which would trip the inverter. One would need at least a 15kw inverter to have a chance of not tripping and the same amount of panels which will increase the cost several times more.

When solar power goes down due to clouds or shade, a motor without VFD would put a lot of burden on the inverter and as the voltage drops its going to take in more amps which will inturn cause the windings to heat and eventually burn(short out).

One could use a 3 phase inverter and a VFD or use a VFD with built in solar mppt charge controller.

All VFD needs DC to convert to AC. So in a solar VFD, its DC to 3 phase AC conversion.

With a regular VFD, it will first convert AC to DC and then again to 3 phase AC. So you eliminate one unnecessary step.

[fordday]

Originally Posted by aim120

His VFD takes the solar DC and converts it to 3 phase AC but with variable frequency (user controlled).

Thank you for the detailed explanation. It really helped to understand the intricacy.

I didn't account the fact he is off grid, so all power required comes from the solar panels only.

What happens in a grid tied setup? Say e.g. I have a 5KW solar setup running a 3KW pump motor. Assuming it runs well when the sun is shining bright. If cloud or shade comes in during running, does it automatically get switched over to grid power?

[aim120]

Originally Posted by fordday

Thank you for the detailed explanation. It really helped to understand the intricacy.

I didn't account the fact he is off grid, so all power required comes from the solar panels only.

What happens in a grid tied setup? Say e.g. I have a 5KW solar setup running a 3KW pump motor. Assuming it runs well when the sun is shining bright. If cloud or shade comes in during running, does it automatically get switched over to grid power?

In a grid tied setup, the solar will only be exporting the current produced. So any excess will be taken from the grid.

If you have a off grid solar inverter, in that case it will take the excess load from the battery, in some models like the Flin Fuzion it takes the excess from battery or the grid, assuming you have a grid connection.

[graaja]

Originally Posted by sagarpadaki

Excellent stuff graaja. The outcome is very neat and functional!

Might I suggest that you coat all the solar panels with ceramic coating...

Thank you for the kind words and the tip about ceramic coating. I will check with the installer about ceramic coating and see if I can do this.

Originally Posted by thanixravindran

Wow, Fantastic graaja. An Off-grid farm like 'Down under' is a dream that can be very rarely realized here. Congratulations and Best wishes.

I can only imagine the smile on your face when the first water was pumped out using solar energy.... I am now interested to go for Solar for my home borewell pump.

I have few questions

1. Is there any reason that you did not consider a single phase pump which I think is available in 230V range? Or in future you want to get the 'Mains' from Electricity board also? I presume you don't have any need for night irrigation which is mostly done when 'Mains' is available.

2. Since you have series connected all the panels, have you considered a scenario when one of the wires can be bitten say by a rat that can stop the entire solar system? (Apologies if this is coming in a wrong way, but since I was an product development engineer, my mind is trained for FMEA).

3. What is the overall DC connection length that is ongoing from the panels to your control room (which I think houses both VFD as well you home inverter)? I guess the poles carry 220V AC to your home from control room and are properly sized and insulated.

4. Did your installer do any full day survey for the sun or shade pattern from morning to evening prior to the installation?

5. Have you considered any insurance for this solar farm set-up? Is anything available?

Your set-up is excellent as per the good practice for the height. The steel-concrete structure at a height upto 3 feet even in roof top is generally rated for winds upto 220Km/hr. I did this research and consultation with Luminous given Chennai has experienced Vardha cyclone couple of years (2016) before my installation.

Please consider a system to wash the panels may be using the same Solar pump water with automation.

Thank you for the kind words, and all the best with the installation of solar for your pump.

1. For a solar VFD where the frequency of the pump is varied according to intensity of solar, I don't think a single phase pump would work.

2. No. I have not considered this scenario. As the panels are raised at a height above the ground, there is very less chance of rats climbing the structure and biting off the wires. In the remote chance that happens, then I will have to just patch up the wire.

3. The panels are located at a distance of around 50 feet from the control room and a 10 sq.mm wire has been used to bring the panel voltage to the control room. The maximum panel current would be 9.5A. The 230V AC line is routed through the posts to the house, and I believe that is also appropriately sized (did not pay attention to this size).

4. No. We did not do a full day study of the location. We just decided based on the surrounding trees and left enough gap based on experience.

5. No. I have not considered to get insurance for the system. Not sure if such an insurance exists and the procedures to get one.

I have made provisions for water connection near the solar panels from the solar pump and used this to wash the panel once. As it takes about 15 minutes to wash the panel and as it is a good workout in the sun that can provide both strength and mobility training along with good Vitamin D, decided to keep it manual

Originally Posted by frewper

Excellent Thread as always Graaja. And what an excellect project to have.

Obvious I am too raising my hand for a few questions.

1. You mentioned you intend to use a PLC for controlling the values. I am assuming you have something else planned to add on the PLC? Since the cost of adding a PLC and programming it might not be cost effective. Even if we go in for the cheapest PLC.

Or do you plan to build it yourself? Then it would make sense.

2. Is cleaning the panels that difficult? Wouldnt just holding the water pipe directly from the pump clean the panels easily. Given its not too high.

3. Since there are no mains, are you planning to keep some small electric generator as a backup.

Thank you so much for the kind words!

1. I plan to use a simple starting level PLC which costs about 10K, and will be doing the ladder programming myself. Also, I will be building the complete control panel myself. So, it shoudldn't be expensive. This is at least a year in the future.

2. Just holding the pipe will not be enough to dislodge the thick layer of dust that gets accumulated. Need to scrub the panels as water is flowing over the panels to completely remove the dust.

3. No. I am not planning to keep a generator. Before this 3kW installation, the small 300W setup used to get off most of the time at around 4AM in the morning. And we used to manage with a cell phone torch light. Plan to do the same if there is any failure

Originally Posted by fordday

First, a big congratulations on your setup. I am sure it gives you immense pleasure when you see the sun's energy put to use on the farm. Hope it gives you a hassle free years of operation.

I wanted to know what exactly is the function of the VFD? You mentioned it shows the frequency at which the motor is running. Doesn't a regular solar inverter creates/matches the normal 50Hz frequency?

Thank you for the kind words. aim120 has very clearly explained the system. In a regular hybrid or grid tie system, when the intensity of the sun goes down, the difference power that is required to run the pump will be provided by the battery or the grid. Because of this the pump can always be run at 230V/50Hz. But with a solar based VFD, as there is no alternate power source to provide this difference power, the VFD adjusts the output based on the solar intensity. With a 3 phase motor, the simplest way to vary the output is by varying the frequency. Like aim120 mentioned a 3 phase hybrid inverter setup would cost close to 2 lakhs whereas the VFD costs about 30K. The downside of the variable pump speed is that the water delivery and pressure is directly proportional to the intensity of the sun. So, if the pump delivers 6000 liters per hour on a sunny day, the delivery can drop to 3000 liters per hour on a cloudy day.

[thanixravindran]

Originally Posted by graaja

I plan to use a simple starting level PLC which costs about 10K, and will be doing the ladder programming myself. Also, I will be building the complete control panel myself. So, it shoudldn't be expensive. This is at least a year in the future.

Hi again - Thanks for the quick reply. I googled and was reading the operation manual of the Solar pump inverter/VFD that you got.

It seems a beast with programmable control and not a simple VFD. Can you please confirm whether it has those Digital inputs (Dry contact/Switches) ports (S1 - S4). You can use it for water level ON/OFF if you go for a tank based system without any PLC control. It has an Aux power supply port (24VDC/200mA) out to power external sensors.

Also, it seems you can add a GPRS module for remote operation which will be fantastic. And possible to connect with Modbus with a RS485 connection which will open up a world of controls.

I read that it can take Mains AC input also in case you want to get a TNEB connection in future and can be configured to use a single phase motor directly by adjusting the control circuit or make it as a 2 phase to induce the flux with one of the switch options.

Kindly check whether your installer has any experience or you can take advantage of these features in your next project.

[graaja]

Originally Posted by thanixravindran

Hi again - Thanks for the quick reply. I googled and was reading the operation manual of the Solar pump inverter/VFD that you got.

It seems a beast with programmable control and not a simple VFD. Can you please confirm whether it has those Digital inputs (Dry contact/Switches) ports (S1 - S4). You can use it for water level ON/OFF if you go for a tank based system without any PLC control. It has an Aux power supply port (24VDC/200mA) out to power external sensors.

Also, it seems you can add a GPRS module for remote operation which will be fantastic. And possible to connect with Modbus with a RS485 connection which will open up a world of controls.

I read that it can take Mains AC input also in case you want to get a TNEB connection in future and can be configured to use a single phase motor directly by adjusting the control circuit or make it as a 2 phase to induce the flux with one of the switch options.

Kindly check whether your installer has any experience or you can take advantage of these features in your next project.

Yes. All the features you have listed are available in the VFD. It is a highly configurable controller.

1. It has all those digital inputs. The On/Off switch right now is connected to one of these digital inputs.

2. Yes. It has a 24VDC aux power supply port which can power sensors.

3. AC input is available in specific models. I skipped this in favor of some other configurable functions in my model.

4. It has Modbus connection as well. I plan to implement a cloud based control system where I will be using this feature to read operational parameters using the PLC as the Modbus master. Even the FlinFuzion inverter has a serial port which I can use to collect data for monitoring. The installer does not have experience in automation, Modbus etc. I will be doing this myself.

I want to first plant trees this monsoon and control the irrigation using manual valves to understand timing requirements. Once I have all the data, I will implement the automation.

[2500cc]

Excellent thought, setup and execution graaja. This is must for all the farming folks considering the power woes from the ESCOM companies.

I have 4 acres of agriculture land which am setting up currently, I'll probably reach out to you in a month or 2 for your guidance and suggestions to setup container house and solar power source.

[showboat]

Originally Posted by graaja

3. No. I am not planning to keep a generator. Before this 3kW installation, the small 300W setup used to get off most of the time at around 4AM in the morning. And we used to manage with a cell phone torch light. Plan to do the same if there is any failure

Graaja,

Huge fan of your threads and this is another great one. Keep being the inspiration to the rest of us. Looking forward to what you're going to grow. I have an organic farm so if you need any advice just shoot me a DM.

I have a couple of these on my farm, that my staff use during long power cuts. They take a long time to charge by just solar, but for the price, it's a good buy. Keeps the solar theme going also.

https://www.amazon.in/wipro-Coral-Re...=3CVQD8DCT9WJD

[PGA]

Thanks a ton for explaining it all so well. I went through it all in 2014-15, had you put up this post a couple of years earlier, I would have saved a ton of effort and some money as well.
I have a 5kva system which powers drip lines in six acres of intensive cultivation in peak north Indian summer. I did try to connect my solar system to power my farm house but dropped the idea as electricity rates went down substantially in our area, it now makes so much sense to take power from the electricity board.

Since your panels are close to the boundary, you may consider installing anti theft nuts to secure the panels, if not already done, they will surely make life very tough for a thief.

[Renukaprasad]

Thanks for inspiring and informative post. I own a 6 acre farm with 3 borewells and a small farm house all running with grid power. Recently added one more bore well and getting a solar pump installed. As the installations are being done by a reputed solar company, I did not bother much about technicalities. Many of my doubts are addressed in the thread and now I understand the basics of VFD and other set ups.
My only question is why the choices of pumps are limited or the dynamic head of pumps are very less (70 meters max for 5 Hp)? My bore well is 550 feet deep and water yield is less (say 3000 liters /Hr). If I choose 7.5 Hp pump for want of better Head, my bore well may not support the high rate of pumping out. Any way out ?

Thanks

[graaja]

Originally Posted by Renukaprasad

My only question is why the choices of pumps are limited or the dynamic head of pumps are very less (70 meters max for 5 Hp)? My bore well is 550 feet deep and water yield is less (say 3000 liters /Hr). If I choose 7.5 Hp pump for want of better Head, my bore well may not support the high rate of pumping out. Any way out ?

I do not have the technical expertise to provide a solution for your problem.

But unlike utility powered motors, where you just connect a motor to the grid and everything works, when it comes to solar, there are so many parameters that need to be matched - panel voltage/current rating, VFD's output current rating, motor's voltage and current rating and number of stages.

Initially, I had contacted a bigger company who told me the only way to do my setup is with a 5HP pump and a 5kW solar panel. The reason is that they try to design a system around the products that they have.

When I contacted the individual installer, he gave me a solution with a 3hp motor and 3.4kW panels which provide about 5000 liters per hour of flow. This is because he was good in matching the specs of all the components. He got a custom pump made at CRI pumps to suit the system. So I have a 3HP pump placed at 250 feet.

If it is not too late, you could call this installer and get his second opinion about the system that you are being proposed. His number is below:

George, Nego Solar, 9626223229, 9362223229

PS: I do not have any affiliation to this installer. I am just a happy customer.