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Misconceptions About Solar Power? What Is The Right Answer? - Science/Technology - Nairaland

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Misconceptions About Solar Power? What Is The Right Answer? by chris81964(m): 12:47pm On Sep 26, 2015
I have been having some exciting exchanges with some experts in solar. We have been trying to determine how they calculate the size of the inverter, the battery bank and the size of the PV.
I have heard 4 batteries 4 panels.
I have heard inverters catch on fire
I have heard 3 kw in panels is too much for 4 batteries. (irrespective of the size)
I have heard you can't run AC on Solar
I have heard the system voltage has no bearing in calculating the battery bank or array size.
I have heard 4 200 AH batteries equal 800 AH. It does not matter if it is 12, 24 or 48 Volts.
I have heard panels are installed facing the east. (hint: the solstices and equinox)
I have heard I can installs panels under a tree or an obstruction.
I have heard. Solar does not work when it rains or when it is cloudy
I have heard solar does not carry Microwave or AC.
I have heard that PWM controllers work very well on huge installations.
We have seen 3 kw in panels with a 20 amp controller
I have heard we tell the customer the inverter size. If he wants to pump water, use his fridge, freezer, microwave and maybe run one AC 10 kva with 8 batteries.
What matters most is the size of the inverter capacity and the battery.
You only need enough solar panel to charge the number of batteries.


Please add your misconceptions and we will take them apart daily one topic at a time.
Solar will work better if we all understand how professionals arrive at calculations

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Re: Misconceptions About Solar Power? What Is The Right Answer? by Nobody: 12:50pm On Sep 26, 2015
angry
Re: Misconceptions About Solar Power? What Is The Right Answer? by Nobody: 12:53pm On Sep 26, 2015
What matters most is the size of the inverter capacity and the battery. You only need enough solar panel to charge the number of batteries.

But If I am an engineer, I will not need solar panel to install constant power as long as the inverter and batteries are available.

Unfortunately, I am not by paper qualification.
Re: Misconceptions About Solar Power? What Is The Right Answer? by chris81964(m): 1:08pm On Sep 26, 2015
victorels:
What matters most is the size of the inverter capacity and the battery. You only need enough solar panel to charge the number of batteries.

But If I am an engineer, I will not need solar panel to install constant power as long as the inverter and batteries are available.

Unfortunately, I am not by paper qualification.

Thank you for contributing. I will add that to the list too.
The tariffs are scheduled to increase. How would you compensate for the higher bills to charge your inverter batteries? The sun is free. Just asking
Re: Misconceptions About Solar Power? What Is The Right Answer? by Nobody: 1:12pm On Sep 26, 2015
chris81964:


Thank you for contributing. I will add that to the list too.
The tariffs are scheduled to increase. How would you compensate for the higher bills to charge your inverter batteries? The sun is free. Just asking

If you understand how your car battery get charged while driving, you would see that the sun is a non entity in this case.
Re: Misconceptions About Solar Power? What Is The Right Answer? by chris81964(m): 1:22pm On Sep 26, 2015
victorels:


If you understand how your car battery get charged while driving, you would see that the sun is a non entity in this case.

Thank you for your contribution. That is also another school of thought to discuss.
Re: Misconceptions About Solar Power? What Is The Right Answer? by chris81964(m): 2:05pm On Sep 26, 2015
Another one. We don't need a charge controller.We connect the panels directly to the battery

Re: Misconceptions About Solar Power? What Is The Right Answer? by chris81964(m): 7:55am On Sep 27, 2015
I have heard 4 batteries 4 panels

That is a gross misrepresentation. The number of batteries have no bearing on the number of panels.
You could have 4 batteries of varying amp hours. 100 150 200 405 1202 do you still use 4 panels? And what size panels? 80, 100 200 or 250 Watts?
The determinant on the PV size is the watt hours you use and how quickly you need to recharge your batteries. If you have a place that you only use on the weekends, then the PV size will not be as big as a place you use every day.

If anyone tells you that you need to match the number of panels to the number of batteries. Move on to another person.

Re: Misconceptions About Solar Power? What Is The Right Answer? by chris81964(m): 7:12am On Sep 28, 2015
I have heard panels are installed facing the east. (hint: the solstices and equinox)

Good morning. More on the myths about solar. The direction you face your panels depends on what hemisphere you live in. For those of us that live near the equator it is not as critical but it helps capture every ray of sunshine. The sun might shine all day but how many hours of direct sunshine do your panels get? It depends on where you live.
If you live in the southern hemisphere you face your panels true North. A couple of reasons. In school they taught you about the summer solstice and the winter equinox. When your days or nights are longer and when the sun is higher or lower in the sky. (remember some people have talked about tilt? that is why). You want your panels positioned in a way that it gets the maximum direct exposure to the sun. (which is about 4 to 5 hours a day). You also want the proper tilt so that it takes advantage of the position of the sun.

Quiz: When during the day are your panels getting the maximum direct exposure to the sun?
Re: Misconceptions About Solar Power? What Is The Right Answer? by chris81964(m): 7:36am On Oct 01, 2015
Another one. We don't need a charge controller.We connect the panels directly to the battery

What does a charge controller do? It regulates the charge from the panels into the batteries. It acts like a switch that turns on and off to make sure the batteries are not overcharged. Two ways to ruin your batteries over charging and under charging. Over charging dries out your batteries. (Your dry cell has electrolyte.) And once the lead plates are exposed good by batteries. Under charging, you controller can't really stop that if it does not get enough from the panels, but your chances are better if you have a controller. It also stops the current from flowing back to the batteries at night.
Can you plug your panels to your batteries? Yes you can. Is it a good idea? No. So when someone tells you to connect the batteries directly to your panels tell them to keep moving.
Yesterday was a busy day so I did not post this.
HAPPY INDEPENDENCE DAY NAIRALANDERS.
Re: Misconceptions About Solar Power? What Is The Right Answer? by kozmokaz(m): 10:34pm On Oct 01, 2015
car ba3s are charged by dynamos in d engine... rememeber d car engine can also b used to generate electricity
Re: Misconceptions About Solar Power? What Is The Right Answer? by chris81964(m): 11:44pm On Oct 01, 2015
kozmokaz:
car ba3s are charged by dynamos in d engine... rememeber d car engine can also b used to generate electricity

Please explain the principle by which this can be done and how we can use it to charge batteries without burning fossil fuels.
Re: Misconceptions About Solar Power? What Is The Right Answer? by chris81964(m): 8:25am On Oct 02, 2015
I have heard you can't run AC on Solar

This is also incorrect. Air conditioners draw a large amount of power over a long constant period. Due to the poor level of insulation of most Nigerian homes, AC run constantly at peak. They struggle to bring the room to the lowest temperature setting that most people leave them on. Hence the draw for extended periods.

If the client wants AC and is willing to pay for it, AC is a worthwhile option that solar will gladly provide. Your pure sine wave inverter produces a constant voltage that is right in the range that AC's enjoy, allowing for the motors to run cooler and more efficiently. Yes AC can be run on solar and in the western world they do.

Watch my video addressing two of the topics. Inverters that catch on fire and batteries that don't last


https://www.youtube.com/watch?v=HDdNu57M_cI

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Re: Misconceptions About Solar Power? What Is The Right Answer? by chris81964(m): 10:16am On Oct 03, 2015
We have seen 3 kw in panels with a 20 amp controller

How do we determine the controller size and the time it takes to charge your batteries?

1. How do you size the controller to match your PV?

There is a formula. We see people put a 40 amp charge controller on 3000 kw in panels on a 12, 24 or 48 V system. This would never work. We have also seen 20 amp charge controllers try to charge 600 AH battery banks.

We will do the easy one first. 600 ah / 20 amps = 30 hrs. A 20 amp charger will take 30 hours (more than a full day) to charge a fully depleted 600 AH battery bank This assumes that there is no load (your inverter or anything else) attached to the battery and there is full sunshine on your panels. So we all agree that a 20 amp charger will never work.

2. How do you match the appropriate controller to the panels capacity you have installed?

Watts / Volts = amps. So if we have 3000 watts in panels and our system is 24 Volts then 3000 / 24 = 125. You need a 125 amp charge controller.
There is are no 125 amp controllers for solar today. So what you do is purchase one 80 and one 60 watt controller. In a pinch I would use two 60 watt controllers. There is a way around this. But it is a discussion for another day.
Having the recipe does not make you a chef.
Have a good day.


https://www.youtube.com/watch?v=0KlDnuUhpp4
Re: Misconceptions About Solar Power? What Is The Right Answer? by chris81964(m): 12:04pm On Oct 04, 2015
I have heard that PWM controllers work very well on huge installations.

This is a correct statement. As long as you can afford to buy the panels a PWM will do the job.
An MPPT allows you to extract more from your installed PV using some proprietary algorithm. You can see a harvest of up to 30% more than you would from an MPPT.
If you can afford it buy an MPPT controller. Never skimp on quality. It will make a difference in the long run.


https://www.youtube.com/watch?v=DrB5DktczDY
Re: Misconceptions About Solar Power? What Is The Right Answer? by kozmokaz(m): 5:37pm On Oct 04, 2015
chris81964:


Please explain the principle by which this can be done and how we can use it to charge batteries without burning fossil fuels.
same principle used in dams wen explain better
Re: Misconceptions About Solar Power? What Is The Right Answer? by chris81964(m): 6:59pm On Oct 04, 2015
kozmokaz:
same principle used in dams wen explain better
So you are saying that I am going to remove the charger / alternator / dynamo from a car and take it to a dam and then what do I do?
You can expand on your subject further. People are really interested in a means of generating power that does not involve fossil fuels. Please explain yourself better.
Re: Misconceptions About Solar Power? What Is The Right Answer? by kozmokaz(m): 8:08pm On Oct 04, 2015
chris81964:

So you are saying that I am going to remove the charger / alternator / dynamo from a car and take it to a dam and then what do I do?
You can expand on your subject further. People are really interested in a means of generating power that does not involve fossil fuels. Please explain yourself better.
lol.... daz not wat i meant dude.... ok let me explain it dis way.... gt a generator coil(dynamo) .... u know it s d turnin of d coil dat generate d electricity....2: fix d coil head to a source dat rotates .(strong refridgerator motor) wen connected to a power source (battery) ... wen u power on d motor, as d motor rotates, it in turn rotate d coil which den produces electricity ... u can also charge ur ba3 from d electricity produced... ther are oda equipments to add buh d major ones are d coil(dynamo) .... fan(motor head) and ur ba3 .... dis was my final year in sec sch practical tho... u can as well add ur own to mak it more dope
Re: Misconceptions About Solar Power? What Is The Right Answer? by chris81964(m): 8:27pm On Oct 04, 2015
kozmokaz:
lol.... daz not wat i meant dude.... ok let me explain it dis way.... gt a generator coil(dynamo) .... u know it s d turnin of d coil dat generate d electricity....2: fix d coil head to a source dat rotates .(strong refridgerator motor) wen connected to a power source (battery) ... wen u power on d motor, as d motor rotates, it in turn rotate d coil which den produces electricity ... u can also charge ur ba3 from d electricity produced... ther are oda equipments to add buh d major ones are d coil(dynamo) .... fan(motor head) and ur ba3 .... dis was my final year in sec sch practical tho... u can as well add ur own to mak it more dope

Thank you for taking time to explain your high school project to us. Now can you tie it to solar and how we can benefit from it.
Re: Misconceptions About Solar Power? What Is The Right Answer? by kozmokaz(m): 8:57pm On Oct 04, 2015
chris81964:


Thank you for taking time to explain your high school project to us. Now can you tie it to solar and how we can benefit from it.
u can den charge d ba3 using solar enegy
Re: Misconceptions About Solar Power? What Is The Right Answer? by chris81964(m): 2:38pm On Oct 05, 2015
I have heard. Solar does not work when it rains or when it is cloudy

This is a question we get asked every time. Will solar work during the rainy season? Will solar work when it rains.
The answer is yes. Your panels will still produce power even though the production is diminished. This is when a really good charge controller is worth its weight in Gold


https://www.youtube.com/watch?v=w7C1Fj6EjZs
Re: Misconceptions About Solar Power? What Is The Right Answer? by chris81964(m): 7:27pm On Oct 09, 2015
What matters most is the size of the inverter capacity and the battery.

That is so far from the truth. What matters most is your usage and your load. This determines the size of your inverter and your battery bank.
Too big an inverter results in standby power that can be a little too much and reduce what you can get out of your batteries.

Too little a battery bank results is power loss at the most unexpected time, poor system performance and potential damage to the batteries.

Take time and size the system to match your loads.


https://www.youtube.com/watch?v=rm_HC8IKIC0
Re: Misconceptions About Solar Power? What Is The Right Answer? by chris81964(m): 8:58am On Oct 12, 2015
I have heard I can installs panels under a tree or an obstruction

Most of you have seen streets lights covered by branches or complete tree branches. Some that even post on Nairaland have installed panels that are shaded by buildings, water tanks etc.

Can you install panels under a tree or an area that causes an obstruction or shadow to be cast on the panel. Yes you can. But will it work?
Your panels contain diodes that open and close depending on shade or the degree of light that hits the surface of the panels. These diodes are designed to stop damage from occurring due to hot spots that may occur within the cells. Shading can cause hot spots. This can cause a performance drop which can affect all the cells and panels withing the string. The result can be a more than 50% drop in performance.
So pay close attention to trees and any objects that can cast a shadow over your panels as the sun makes it arc in the sky.

http://solarinsolation.org/
Re: Misconceptions About Solar Power? What Is The Right Answer? by chris81964(m): 12:01pm On Oct 14, 2015
Hello from the Nigerian Alternative Energy Expo in Abuja

Re: Misconceptions About Solar Power? What Is The Right Answer? by chris81964(m): 9:52am On Oct 26, 2015
An installer I met earlier this year bragged about an installation he did for a customer in the east. He connected 7 batteries for a customer's 24 volt inverter. It has been working for over 6 months and the customer is happy.
He wanted to do installations for me.
Re: Misconceptions About Solar Power? What Is The Right Answer? by c0ogumo(m): 8:28pm On Oct 26, 2015
chris81964:
An installer I met earlier this year bragged about an installation he did for a customer in the east. He connected 7 batteries for a customer's 24 volt inverter. It has been working for over 6 months and the customer is happy.
He wanted to do installaltions for me.

Chris, Is that a typo on your end or did he actually installed 7 batteries because the number "7" is an odd number. Do you mean 8 batteries? Or 6 batteries
Re: Misconceptions About Solar Power? What Is The Right Answer? by chris81964(m): 1:12am On Oct 27, 2015
c0ogumo:


Chris, Is that a typo on your end or did he actually installed 7 batteries because the number "7" is an odd number. Do you mean 8 batteries? Or 6 batteries

No Typo. There is so much scary stuff out there.
Re: Misconceptions About Solar Power? What Is The Right Answer? by chris81964(m): 7:26pm On Nov 06, 2015
Will you pay N630k for an 800VA Victron, inverter, two 200 AH Hoppecke 6 V batteries, one 250 Watt panel, one 30 amp charge controller, a roof rack and assorted cables?
Let me know your thoughts.
http://www.victronenergy.com/inverters-chargers/multiplus-12v-24v-48v-800va-3kva

Re: Misconceptions About Solar Power? What Is The Right Answer? by chris81964(m): 8:48pm On Dec 11, 2015

1 Like

Re: Misconceptions About Solar Power? What Is The Right Answer? by chris81964(m): 5:41pm On Dec 19, 2015
http://batteryuniversity.com/learn/article/equalizing_charge

BU-404: What is Equalizing Charge?

Know how to apply an equalize charge and not damage the battery.

Stationary batteries are almost exclusively lead acid and some maintenance is required, one of which is equalizing charge. Applying a periodic equalizing charge brings all cells to similar levels by increasing the voltage to 2.50V/cell, or 10 percent higher than the recommended charge voltage.

An equalizing charge is nothing more than a deliberate overcharge to remove sulfate crystals that built up on the plates over time. Left unchecked, resulting sulfation can reduce the overall capacity of the battery and render the battery unserviceable in extreme cases. Equalizing charge also reverses stratification, a condition where acid concentration is greater at the bottom of the battery than at the top.

Experts recommend equalizing services once a month to once or twice per year. A better method is to apply a fully saturated charge and then compare the specific gravity readings (SG) on the individual cells of a flooded lead acid battery with a hydrometer. Only apply equalization if the SG difference between the cells is 0.030.

During equalizing charge, check the changes in the SG reading every hour and disconnect the charge when the gravity no longer rises. This is the time when no further improvement is possible, and a continued charge would have a negative effect on the battery.

The battery must be kept cool and under close observation for unusual heat rise and excessive venting. Some venting is normal and the hydrogen emitted is highly flammable. The battery room must have good ventilation.

Equalizing VRLA and other sealed batteries involves guesswork. Good judgment plays a pivotal role when estimating the frequency and duration of the service. Some manufacturers recommend monthly equalizations for 2 to 16 hours. Most VRLAs vent at 34kPa (5psi), and repeated venting leads to the depletion of the electrolyte that can lead to a dry-out condition.

Not all chargers feature equalizing charge. If not available, the service will need to be done with a device that is designed for this service.

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