tivta:
Gbam, this says it all. Stc is the rating used under normal conditions but due to the weather in Africa we are above standard conditions. Bodegeorge take note. Traveling around the world does not guarantee knowledge.

Where did it say 100% or 120% Efficiency.

Have you guys thought about companies labelling panels with greater than or equal power to the nameplate rated power. A 300W panel could be labelled 270W

For example, in the picture attached (Solarworld 270w)
Multipling the max voltage and max current give approx 272.23

pheleix:

Where did it say 100% or 120% Efficiency.

Have you guys thought about companies labelling panels with greater than or equal power to the nameplate rated power. A 300W panel could be labelled 270W

For example, in the picture attached (Solarworld 270w)
Multipling the max voltage and max current give approx 272.23

pls read the Wikipedia article properly

richmon74:


It's such a pity that in your 15yrs of electrical engineering practice you have always been limited to environments where energy conversions from SOLAR PANELS stay within 100%.

But in my 2 months of renewable energy apprenticeship I av installed 12 of 255w solarworld solar panels at Unity road in Lekki in Lagos (a very easy place to locate in case anyone wants to chexk it our) which is by calculation 3060w and the Outback FM80 charge controller records a Maximun Wattage output from it to be 3654w as shown in the pictures below. Or maybe the charge controller is faulty or I can't read the digits very well.

Maybe I need a better explanation to that readout

On a different issue entirely, when looking at the 2nd picture attached to the quoted post above, it seems the panels were all not all installed with the same elevation. Wouldn't that affect output or it was just looking like that in the picture?

I am making this submission in order to stimulate ideological discussion and to dismiss hear says and half truths.

Solar panels power are rated at Standard Test Conditions (STC), but with many variables that can hardly be predicted or controlled in real life. Some of the variables include temperature, solar insolation, air mass, air velocity, longitude and latitude, angle of installation, angle of the sun, clear cloud conditions, dirty panels etc.

Efficiencies of the commercially available solar panels range between 10 – 20% at STC where all the variables mentioned above are kept constant. Efficiency of Suntech 200W mono panel is 15% and about the same for Solarworld 255W. Fast forward to real life conditions, where for every 1 degree rise in temperature above 25 degree C, maximum power generated is reduced by 0.38% for Suntech 200W panels and 0.45% solarworld 255W (see attached snip and datasheet of both panels). This could be a 10% loss on each panel on a sunny day and this is an ever increasing factor called Temperature coefficient.

Most of the extra insolation received in Lagos (5000W/m2, see attached Document) in the day is lost due to environmental conditions rather than bad installation as it is claimed. An average of 50% of same insolation is covered by the clouds in the sky.
Yes, we are above the STC conditions, but it works against us! This was clearly stated in the Wikipedia article. Travelling round the world does not guarantee knowledge especially when you are sightseeing and window shopping in malls, careful study and paying attention to details does.

@Tivta, I am not bodegeorge, I am bodejohn, kindly pay attention to details!

bodejohn:
I am making this submission in order to stimulate ideological discussion and to dismiss hear says and half truths.

... is an ever increasing factor called Temperature coefficient.

Most of the extra insolation received in Lagos (5000W/m2, see attached Document) in the day is lost due to environmental conditions rather than bad installation as it is claimed. An average of 50% of same insolation is covered by the clouds in the sky.

Very interesting submission...
I especially like the insolation graph. I need the one for Cross River state.
The bolded above is your opinion, as there're no empirical data to substantiate them.
A proper installation can generate 30% more power in the same Lagos example you used, all other conditions assumed constant(including panels from the same manufacturer).
Temperature sensitivity of both the Suntech and Solarworld panels for the SAME power ranges are within the industry average.
Panel manufacturers use different material qualities for their different brands. Compare the datasheet for the 250w range of panels of different manufacturers.
I do agree with you that with TOP brand manufacturers, for the SAME rated panels ranges, it all boils down to OPTIMAL installation and irradiance for your area.

Yes, we are above the STC conditions, but it works in our favour with optimal installation, including Solar Tracking if you can afford it.

@ Barezzi, I did not assume any of the values I used, I was only lazy, atached is the insolation graph, it was the average of recorded valves in Nigeria for 22yrs.

My aim is not to run any manufacturer down, the more reason I added suntech that we have known to be good from experience. You will notice that they have similar perfomance on paper.

30% improved power generation through proffesional installation is subjective but I respect your opinion.

pheleix:

Where did it say 100% or 120% Efficiency.

Have you guys thought about companies labelling panels with greater than or equal power to the nameplate rated power. A 300W panel could be labelled 270W

For example, in the picture attached (Solarworld 270w)
Multipling the max voltage and max current give approx 272.23

Yeah, I noticed it too, but I see the manufacturer simply rounded down to the nearest whole number.
That's a reduction of 0.8%!
So labeling a 300w panel 270w will be an 11.1% reduction!!
What's the relationship between 0.8% and 11.1%??

@bodejohn,noted. At least the thread is alive and active once again.

bodejohn:
@ Barezzi, I did not assume any of the values I used, I was only lazy, attached is the insolation graph, it was the average of recorded values in Nigeria for 22yrs.

My aim is not to run any manufacturer down, the more reason I added suntech that we have known to be good from experience. You will notice that they have similar performance on paper.

30% improved power generation through professional installation is subjective but I respect your opinion.

The guys who handled my installation did a very bad job , they installed my panels directly on the zinc roof, and you know what temperature does to panel voltages, and its max power by extension.
At least with mounting racks, they would have been some clearance for air circulation/cooling.

I miss the feeling of DIY, I may teardown the installation and do it myself cc: GeorgeD1.
Or get Richmon74 to do it professionally...

please can anyone recommend a good battery charger/maintainer for me so that i will be able to use it to charger standby batteries. cause i had to take one of my batteries to this automobile batteries men for charging, after charging for several hours and i carried out test on the batteries but it didn't charge well. or if you have any charging method it is also welcome. thanks

urusky247:
please can anyone recommend a good battery charger/maintainer for me so that i will be able to use it to charger standby batteries. cause i had to take one of my batteries to this automobile batteries men for charging, after charging for several hours and i carried out test on the batteries but it didn't charge well. or if you have any charging method it is also welcome. thanks

No idea.
cc: kiekie, richmon74

urusky247:
please can anyone recommend a good battery charger/maintainer for me so that i will be able to use it to charger standby batteries. cause i had to take one of my batteries to this automobile batteries men for charging, after charging for several hours and i carried out test on the batteries but it didn't charge well. or if you have any charging method it is also welcome. thanks

What kind of battery are you trying to charge?
Whats the voltage and capacity.

Please contact me for more info

Whatsapp:973-204-1296
BBM PIN: 79395A2D
email: molley4real@hotmail.com
www.solardepotng.com

tivta:
Gbam, this says it all. Stc is the rating used under normal conditions but due to the weather in Africa we are above standard conditions. Bodegeorge take note. Traveling around the world does not guarantee knowledge.

The article you quoted mentioned that the highest achieved efficiency is around 47% at STC. The efficiency will increase under other conditions but I don't see any mention of 100% efficiency.

I also agree with@ bodejohn and basic physics that there's no energy conversion that can be 100% efficient. From the article you posted, Solarworld panels ratings are under-rated when installed under right conditions in Nigeria

tundebabzy:


The article you quoted mentioned that the highest achieved efficiency is around 47% at STC. The efficiency will increase under other conditions but I don't see any mention of 100% efficiency.

I also agree with@ bodejohn and basic physics that there's no energy conversion that can be 100% efficient. From the article you posted, Solarworld panels ratings are under-rated when installed under right conditions in Nigeria

At bolded, it refers to CELL energy conversion. That is its effectiveness in converting solar energy to heat and electricity. This is purely a function of cell design, and the quality of materials used in its construction.
No panel has 100% cell efficiency. What's the industry average??

For your post in red, I suggest you read up on solar panel technology, it'll clear up a lot of misconceptions

PS, I'm not holding brief for solarworld, suntech or sharp.

Barezzi:

At bolded, it refers to CELL energy conversion. That is its effectiveness in converting solar energy to heat and electricity. This is purely a function of cell design, and the quality of materials used in its construction.
No panel has 100% cell efficiency. What's the industry average??

For your post in red, I suggest you read up on solar panel technology, it'll clear up a lot of misconceptions

PS, I'm not holding brief for solarworld, suntech or sharp.

The cell is the core of solar panel technology. By the time it used to make solar panels the efficiency would have further reduced. Because I know you know your onions, I had to ask Google. A search on 100% percent efficient solar cells turned out that its still a dream. World record efficiency is still in the 40s and lower for solar panels.

Here is an article from Yale published 3 days ago (today is 15 December) discussing how nice it will be to hit 50% efficiency - http://e360.yale.edu/feature/will_new_technologies_give_critical_boost_to_solar_power/2832/
and then another published in February that listed efficiency records - http://cleantechnica.com/2014/02/02/which-solar-panels-most-efficient/

tundebabzy:



The cell is the core of solar panel technology. By the time it used to make solar panels the efficiency would have further reduced.

... Tunde, you still don't get it...
Cell efficiency and the power rating of a solar panel are two different parameters.
A solar cell at 50% efficiency simply means it can convert 50% of sunlight to electricity
& heat at STC.(In very simplistic terms). The higher the cell efficiency, the more
kwh(energy) of electricity it can produce. In practical terms, its akin to comparing the
screen resolution of a Tecno phone and an iphone 6 of same dimensions . Imagine both
phones are solar panels, and the pixels - solar cells. The Tecno phone with low efficiency
cells, will produce low kwh(energy), whereas the iphone 6 with high efficiency cells will produce high kwh(energy).
The practical implication of this is that for your limited roof space, u want solar panels with high efficiency cells.

Whereas power rating is the amount of dc power the panel can produce at STC.
That the cell efficiency is 50% does not mean that the solar panel performs at 50% of its nameplate power.

The koko of the matter is if its possible for a 250w solarworld panel to deliver 260w, hence producing more than its nameplate rating.

A solar panel technical datasheet contains all the info you need concerning any panel.
There's a parameter called Power Tolerance, see attached datasheets...
Power tolerance is a measure of how much higher or lower the POWER OUTPUT of a
solar panel might deviate from its NAMEPLATE rating.

Power tolerance for a 250w panel from the datasheets attached:
Solarworld panels: +5%/-0%
Sharp Panels: +5%/-0%
Suntech Panels: +5%/0%

The 250-watt Solarworld panel with a +5%/0% power tolerance can actually produce anywhere from 250 watts to 262.5 watts under ideal conditions.

For some strange reasons, I cant attach the datasheets... i'll try again later.

Barezzi:
For some strange reasons, I cant attach the datasheets... i'll try again later.

Check the size of the document.
You can print it to pdf or if it is in the pdf format already, you can split the pages to reduce the size.

Barezzi:

... Tunde, you still don't get it...

The koko of the matter is if its possible for a 250w solarworld panel to deliver 260w, hence producing more than its nameplate rating.


The 250-watt Solarworld panel with a +5%/0% power tolerance can actually produce anywhere from 250 watts to 262.5 watts under ideal conditions.

I never disputed the fact that solar modules can produce more than produce more than its rated output.

tundebabzy:

I also agree with@ bodejohn and basic physics that there's no energy conversion that can be 100% efficient. From the article you posted, Solarworld panels ratings are under-rated when installed under right conditions in Nigeria

Or did I?

My brothers, I've been missing in action as this thread rumbles on. I actually carried out my installation in June and had all the intentions of dazzling you all with my handiwork. It was all going well until I plugged my new phone with the pictures into a socket while running a generator before completing the work. As it turned out, the gen was putting out fluctuating voltage and it promptly wrecked my new phone. That was the end of my bright idea of a photo-diary of the installation .

Undeterred, I soldiered on and managed to complete the installation to just over 50% of the design capacity, before I had to get back to work. I'm hoping to add the additional panels soon.

Briefly, the system design is 2 x 3kW arrays for a total of 6kW. To date I've installed 12 panels at 300W (6 per array) for a total of 3.6kW.
Each array has its own charge controller serving a dedicated 48V battery bank. The two banks are then combined in parallel prior the inverter/charger.

A switch-over on the main board allows me to charge the batteries through the inverter/charger from either N.E.P.A (wishful thinking) or generator on consecutive cloudy days. The inverter I'm using can automatically switch between utility (NEPA / GEN) or DC Mode (Batteries) if it detects AC power (or lack of) in about 8 milliseconds. I've sought to protect it from N.E.P.A and crazy generators with a Prag 10kVA servo stabilizer as suggested on this thread. What I could not protect it from was the custodian that was to look after it in my absence, but that is another story for later.

At the same time, I replaced almost all the bulbs in the household with low power led equivalents and used time-limit switches on water heaters and pumps. It was hard work but worth it as there we were, in early June, enjoying steady, unblinking, 'clean' electricity. It was wonderful.

I'll post the pictures that the phone warranty people were able to save later.

tundebabzy:


I never disputed the fact that solar modules can produce more than produce more than its rated output.


Or did I?

Yup you did... You say they're under-rated. I say they are not

@ ilenaira,
Nice one. Please confirm if you have seen up to 30A charging current per battery bank from your CC.

Barezzi:
@ ilenaira,
Nice one. Please confirm if you have seen up to 30A charging current per battery bank from your CC.

@Barezzi, the CC I'm using is capable of 60A. In fact during the wet and cloudy month of June that I was home, the highest I saw was about 22A on each CC on a visual check that things were working. I'll make use of the logging feature to confirm.

On my short visit this month, I was too busy figuring out what the ****** I'd entrusted it all to had done to my inverter. The good news was that because I used dedicated CCs instead of the integrated pwm charger on the inverter, the batteries were on float. The bad news was that I could not make use of fully charged batteries because the inverter would not power up ( ******** had been fiddling with the connectors for the detachable display panel. and probably caused a short somewhere, why I trusted him in the first place I don't know)

The CCs have performed well so far, the only regret is they didn't tell me they were about to launch a snazzier looking version so mine looks dated compared to the new design below.

Barezzi:

Yup you did... You say they're under-rated. I say they are not

Case dismissed then

ilenaira:


@Barezzi, the CC I'm using is capable of 60A. In fact during the wet and cloudy month of June that I was home, the highest I saw was about 22A on each CC on a visual check that things were working. I'll make use of the logging feature to confirm.

On my short visit this month, I was too busy figuring out what the ****** I'd entrusted it all to had done to my inverter. The good news was that because I used dedicated CCs instead of the integrated pwm charger on the inverter, the batteries were on float. The bad news was that I could not make use of fully charged batteries because the inverter would not power up ( ******** had been fiddling with the connectors for the detachable display panel. and probably caused a short somewhere, why I trusted him in the first place I don't know)

The CCs have performed well so far, the only regret is they didn't tell me they were about to launch a snazzier looking version so mine looks dated compared to the new design below.

My set up of 3.6KW panel and 520AH batteries (2 string of 260AH in parallel) have been delivering above 30A charging current. This depend on draw down overnight on batteries and sun intensity.

salam12:


My set up of 3.6KW panel and 520AH batteries (2 string of 260AH in parallel) have been delivering above 30A charging current. This depend on draw down overnight on batteries and sun intensity.

That's great news. I'll keep a closer eye on it with logging but its good to know that the batteries can be fast charged when necessary.

Panels in situ.

ilenaira:

That's great news. I'll keep a closer eye on it with logging but its good to know that the batteries can be fast charged when necessary.

First familiarize yourself with the controller and choose optimum charging setting taking into account best absorption time (considering your residual load). Some controllers require end amp value to ensure proper float setting. All these put together will ensure optimum charging without undercharging or over charging the batteries.

tundebabzy:


Case dismissed then

both arrays

Brackets for tilt, cooling and securing

UV rated cabling and connectors