₦airaland Forum

Oshomo12:
Sorry for not making myself clearer, Feb was exactly one year I installed those panels, and 9.4amps was the max seen within the period of a year. I did the test this year Feb. I have a record of the max of each month thru out this period. I take my records between 12:10-2:20pm

Oshomo12:
I wanted to initially, but my roof was steep( I feared the wind issue, so I stopped). What I should be getting from the panel should be around 17.9 amps @ around 7-9 deg. But after I factored in the losses due to the angle, I should have about 13-14 amps. But never got that, as in never saw it once!
After the test, I decided to give good spacing, the angle reduced by just 6 ie from 26 to 20 deg. I get around 13.5~13.9 amps now, never saw 14.7 amps again. So I ve decided never to use roof mounting for my panels again, cos my target is to get around 3000 watts of panels. So ground mount is what I will do now.

Oshomo12:
I wanted to initially, but my roof was steep( I feared the wind issue, so I stopped). What I should be getting from the panel should be around 17.9 amps @ around 7-9 deg. But after I factored in the losses due to the angle, I should have about 13-14 amps. But never got that, as in never saw it once!
After the test, I decided to give good spacing, the angle reduced by just 6 ie from 26 to 20 deg. I get around 13.5~13.9 amps now, never saw seen 14.7 amps again. So I ve decided never to use roof mounting for my panels again, cos my target is to get around 3000 watts of panels. So ground mount is what I will do now.

Oshomo12:
@DMerciful
Anyways, u are correct I am wrong. Maybe I don't know what I am doing, but that is what I have observed and reported. Thank u for ur time.

Oshomo12:
Lol.
There was no cloud cover my brother! I have watched this cc for weeks around that same time (done my experiment in February, peak of the heat at my side). That was the highest current seen so far(9.4amps, even with a resistive load on, eg iron) before I decided to carry out the test. Never saw that current again(14.7 amps), after my experiment( still within same period). Until I gave some space, very good spacing I mean, between the roof and the panel.

Oshomo12:
I will disagree with u on this(less than 5%?). The experiment I carried out shows otherwise. I had two panels flat on the roof, with very little airflow. Between 12:30 and 1:00pm I was getting max of 9.4 amps. These panels should give me nothing less than 14amps( though the angle was around 26deg). I check d temp under the panels, it was very high. What I did was that I have my water pump connected to hoss, and I showered it on panels and the surrounding roof. This last for about 3mins, when I got inside to check the current I was pulling, I could see around 14.7amps! After some time, it went back to around 10 amps. This is what I observed, I want to believe that is more than 5%. The only thing I did was just to cool them down.

Oshomo12:
Bros I hail o. I am sure u did not read thru my whole suggestions. Spacing one of the Reasons..... There is anoda part I talked about. Thank u.

DMerciful:
All

Contact me for the following products

40A 12/24v output 100v solar input MPPT Epever-65k
50A 12/24v output 100v solar input MPPT Fangpusun blue controller with display-70k
60A 12/24/36/48/60V output 150v solar input Fanfpusun controller-160k
12/24V battery balancer-14k

see my signature for contact details

Oshomo12:
hello, I agree with ur words, but the issue here is that these particular panels lie flat on the roof with no or very little air flow under them. so they will get very hot, and reduce the efficiency to about 50%.

earthrealm:
ooh, i didnt get that part -- so his panels are flat on the roof?..
if so thats a bad idea like the poster above stated, get a local welder to fabricate a short rack for you, using angle iron, if you have a fair bit of trignometry, you can calculate the height of the legs to help you achieve an angle closer to 10/15 deg inclination,---- ie make the front or hind legs of the rack shorter or longer as the case may be, the legs shudnt exceed 12inchies to avoid instability and wind factors

HeartforGod:
Thanks DMerciful,

I can do that but getting required length of 16mm copper cable to reconfigure the setup can bore a serious hole in my pocket.

I was considering building a rack to elevate the panels to have a tilt of about 10 - 15 degrees. With this, i may get better harvest and also there will be free flow of air around the panels, thus keeping them cool. What do you think? Wind force on panels during torrential rain is my only fear.

HeartforGod:
Thanks Earthrealm,

My batteries are still performing fine and they are 220ah mercury tubular FLA (15.8kwh battery size). The distance from pv to cc is about 35ft completed with 10mm copper cable. Also, cc is connected to the battery busbar with 2 metre long 25mm fine stranded copper cable.

Saipro:
Replying in the order of your observations

1. I agree the logs could be improved. One of the reasons I converted it to my backup CC
2. Your observations are accurate. The SOC algorithm is actually quite accurate too. It took about a month of careful (translated as almost hourly) monitoring to decipher how it does it.

First of all, its calculations are based on the values you set for absorb as upper limit and low voltage disconnect as lower limit. Secondly, the percentages are calculated based on those values during typical operation. However, if you successfully complete an absorb charge, the upper limit is recalibrated to the float voltage while the lower limit is recalibrated to your rebulk (boost volt reconnect) voltage. The moment you enter rebulk phase, the calibration drops the lower limit back to low voltage disconnect thus, most times, you'd hardly see it display above 70% unless you hardly ever discharge it below you rebulk voltage.



That illustration above explains why you might see 95% at 47V (absorb phase) but 100% at 46V (float phase)



Not to rain on your parade but I hope you're aware the CC does slightly overestimates what it does. It however does a good job nonetheless. Opening it up, it appears to have a very similar DC-to-DC conversion system like the MorningStar MPPT CCs. Very efficient. Its Achille's heel (like its prototype, the MorningStar) is in the slower sweep and recalculation algorithm. Outback, Magnum, Midnite and Xantrex MPPT use similar sweep algorithms (very efficient) but have greater conversits you based on your requirements, constraints and budget.

I chose Midnite for personal reasons. I however have a technical reason for porting to Midnite : cloud cover is very fickle we slower scanning iTracer. In addition, under similar test conditions, the Outback and Midnite CC charge FLA batteries. This is a purely personal set of tests run over a period of months. Do not use my inference for your own system design. I accept no culpability if your system detonates.

bigrovar:
To be clear. Only the Itracer model of Epsolar (their most premium offering) offers the functionalities you listed. The Tracer A and BN series have very little close to useless logging functionality and their algorithm for calculating SOC can drive the uninitiated mad neither do they have voltage sensing cables. The RN series is even worse. That one has no log function whatsoever, neither does it have adjustable voltage setting. That is their entry level device. Yet Epsolar still gives you the best value for your money. Especially the Tracer A series. BN series should be avoided like a plaque.

mcTrinity:
Lolz... the SCC SOC algorithm is designed to read in inverse proportion to battery voltage (imagine!) ... I usually see readings like
SOC 45% at 50V
SOC 60% at 49V
SOC 95% at 47V
SOC 100% at 46V.... what the heck!!!?

Lwkmd4h! initially I thought it's either recession was affecting my sight (Lolz) or I don't really know what SOC is again..

But then, Epsolar is a monster!!!! vomits current like kilode!

earthrealm:
though i hate 2 things about my 60a epsolar cc, especially the first point, its standard on MS n fangpusen CC

1. the log is not robust enough, it doesnt log daily kwh/ah harvest daily
2. its soc algorithm is wack, always wrong

durodee:
Excellent CC. EPSolar I presume? With 42+ temp my CC still harvested 1.3kw from 1.52kw Mono Solarworld panels yesterday. Sorry for repeating the obvious : CC matters!!

foonshur:
boss, is dat hw much its pumping to the batteries, or how much its getting from the panels?

mcci:
Today marks 12 months since I embarked on RE journey and 10 months living off-grid.

It's been a rewarding experience to say the least, even though much improvement is required.

Hence, I give profound gratitude to the Eternal Source of Light that gave us the sun to give warmth and light.

And more blessing to all who ask questions and those who lovingly respond for the progress of everyone on this forum.

jazzman2:
Sir, if you read my previous postings, I have always emphasized 100% off-grid systems that are comprised of predominantly day-time AC loads. It may be an office or a business premise or even residential that require loads that run mostly in the day-time. Mind you, people have different solar power requirements, so don't restrict your understanding to only traditional dc-coupled residential off-grid systems.

In this type of off-grid system, the overall energy conversion efficiency is very high (in the high 90's) as energy from the panel only undergoes 1 conversion cycle (DC to AC only) and this energy is consumed as AC directly. Charge controllers are not required in this system.

In the traditional DC-coupled systems, which you may be very familiar with, you have DC to DC (charge controller), DC to battery (battery chemistry; very poor efficiency for lead-acid batteries) and DC to AC (Inverter) conversion. Energy is lost at every stage of conversion. Overall energy conversion efficiency for traditional dc-coupled systems is generally low.

In conclusion, my emphasis or talking point IS about harnessing the high energy conversion efficiency of grid-tie inverters AC-coupled to battery based bi-directional inverters for off-grid systems where the primary load is day-time AC loads.

Check out this link on the efficiency figures: http://www.northwindre.com/article/ac-coupling-converting-your-grid-tied-pv-system-into-a-high-efficiency-battery-backup-system


Thank you.

Penuelseun:
It seems grid tie inverters are better & more efficient than battery based ones due to the what I read here, my question is that can I use it as off grid coz I am somehow confused or can it be used only in the presence of the national grid?

dejidotun2000:
Please can you compare and contrast between fangpusun mppt 100/30 and epever 3210A

istoctober:
l had to open this account to tell this story and l know that l will be bashed for this but l really need to get it off my chest.
it was in 2014, that l cheated on him and since then, l have not been myself. l have confessed to Pastors but l can't forget it and my mind keep telling me that God has forgotten about me cos whenever l pray, l find it difficult to concentrate and that's why l want to confess to him.
l know he will send me packing because he said something like that to me and the fear is what is keeping me from confessing to him. l don't want to be disgraced out of my home cos my husband will definitely do it.
l can't blame him for my shortcomings but myself for allowing devil into my home.
l really need your advice for help.... You can curse me but l deserve it for being a loose woman but l seriously need help cos depression wants to take over my life that l think of suicide to escape shame and mockery from people in case he finds out.

efuro:
thanks for your commitment to solar. I also note that your prices are quite friendly too. this & your after sales advice will endear new enthusiast to you.

My respect!

zeestone99:
Bros use the 24v hybrid, i bliv it's a pure sine wave inverter. get a proper charge controller Mppt preferably(I dnt trust the controller embedded in hybrids) n u gud 2 go

pranil:
A grid is a legal term referring multiple energy sources connected together for distribution to multiple legal entities so when you call an inverter grid tie it means It is coupled to other energy sources which are regulated based on national laws
Infact based on your recommendation the first search of grid tie inverter brought me to wikipedia

https://en.wikipedia.org/wiki/Grid-tie_inverter

Quote " A grid-tie inverter converts direct current (DC) into an alternating current (AC) suitable for injecting into an electrical power grid, normally 120V RMS at 60Hz or 240V RMS at 50 Hz. Grid-tie inverters are used between local electrical power generators: solar panel, wind turbine, hydro-electric, and the grid.[1]"
In order to inject electrical power efficiently and safely into the grid, grid-tie inverters must accurately match the voltage and phase of the grid sine wave AC waveform.
Some electricity companies will pay for electrical power that is injected into the grid. Unquote

The emphasis is here again GRID-TIE - .
A simple google search will also take you to various manufacturers use of grid tie inverters recommendation and certifications for grid tie which specifically refers to connecting to local distribution grid

Please note that Grid tie inverters are not only frequency based control but they require a complex mechanism to detect abnormal grid conditions such as power swings and ramp rates which are different for every country . A grid tie inverter can also inject VAr into the system or disturb the static var compensations as well as contribute to harmonics

Just to make point clear about google I am not some D.i.Y enthusiast who has read on internet but a practicing consultant for more than 25 years and in renewables for more than 9 years for a leading German consulting company . I have advised utilities and private companies in many countries both in east and west africa on Power systems , renewables and sustainable energy . I use off grid system for my house as a hobby and out of necessity and constantly experimenting with it . But I am worried when people are not aware of the dangers the systems will try to take only partial knowledge and create problems down the line for the entire solar enthusiasts
If interested you can have a look at the publication coauthored by me for ministry of power on Nigerian Electrical system with emphasis on Renewables and rural electrification
http://www.energyplatformnigeria.com/images/Library/Energy_Sector_Study_(2nd_Edition)_-_GIZ_NESP_2015.pdf
http://www.energyplatformnigeria.com/index.php/overarching

Every responsible inverter manufacturers will tell you that in places of weak grid like Nigeria Grid tie or even AC coupled systems are bad idea . It can lead to instability , flickers and other unanticipated issues .


See the attached snipped from official victron user forums where Victron has replied to exact same question -
https://www.victronenergy.com/live/ess:design-installation-manual

P.s. I am not stopping people from using the grid tie inverters just let them be aware that there are both technical and legal pitfalls ahead of them specially when Grid tie inverters cost much higher than offgrid /hybrid inverters and have lower overall efficiency in a typical residential house with battery backup .( converting solar DC to Ac and then back to DC to charge the batteries) . Unfortunately due to severe requirements placed on them because of grid tie they turn out to be more reliable and durable then typical offf grid inverters and hence preferred even for off grid

Barezzi:
Thanks Chris. I got tired typing the same thing...

jazzman2:
Thank you Chris for the education. Many people dont know what AC coupling with grid-tie systems is. Grid-tie should NOT always be associated with back-feeding to the national grid. It can be used on simulated "local" grids where frequency shift control or load diversion can be employed to control excess power generation and protect the battery bank.