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Stats: 2,097,916 members, 4,537,659 topics. Date: Monday, 22 October 2018 at 04:29 AM
|Re: Solar Energy, A Complement To FTA by Barezzi(m): 10:07am On Apr 16|
Well, that poor solar yield will refill his batteries, while yours will still be struggling at bulk stage
Seriously though, i may sell one of my kidneys to go Lithium. My goal is a 400Ah LTO bank
|Re: Solar Energy, A Complement To FTA by bigrovar(m): 11:24am On Apr 16|
Energy storage is at the mid way point of its transition from Lead Acid due to pressure to find a more sustainable means of generating energy. I honestly see lithium to be a stop gap technology that might soon be superseded as more research money is thrown at solving the energy storage problem. Lithium is still a rare earth material available in very few places on earth. Even if the technology stabilises I expect price would go down up to a point thanks to technology and then shoot up as the low price drive demand .. and that demand would eventually outstrip the supply of lithium. I strategy is to sit and wait and see how it all pans out. The high cost of Lithium now is what is funding many of the research into making it a stable commodity and the raise of electric cars will put more pressure into pushing down price of energy storage and lead to the creation of turnkey all in one solution. My next major upgrade will still be lead acid based probably see what the next 5 years will hold.
|Re: Solar Energy, A Complement To FTA by GeorgeD1(m): 11:43am On Apr 16|
you echoed my thoughts exactly. i like to think of myself as a very practical person (maybe it has a lot
to do with my kind of profession), so i work with hard facts and not just theories. my analysis for battery
bank sizing had a typical scenario for 50% dod which you aptly stated in your comments.
|Re: Solar Energy, A Complement To FTA by GeorgeD1(m): 11:50am On Apr 16|
this is getting quite interesting, isn't it? if 300ah for lead-acid equals 100ah for lithium it then
means we have to ultimately change the way we calculate our power fundamentals, i.e p=iv.
unfortunately i'm yet to see any documentation in support of this. i'd be happy if you could give
any references. at least that would be a good starting point.
|Re: Solar Energy, A Complement To FTA by GeorgeD1(m): 12:00pm On Apr 16|
it's really the big energy conundrum playing out all over again. i definitely think the future
belongs to some other storage medium besides lead-acid. but whether lithium is the answer is
what i've been trying to convince myself about. unfortunately, all the replies gotten so far fall
short of that basic answer. emotions? yes. sentiments? yes. hard facts backed by sound
financial analysis? zilch!
|Re: Solar Energy, A Complement To FTA by bigrovar(m): 12:11pm On Apr 16|
You sacrifice system efficiency in the process. It all depends on how wiring is configured and how good the batteries are. for anything higher than 3kw inverters I prefer 48v. Issues of batteries going out of sync are common in parallel connection more so than even in series. The main cause of these problem is bad wiring. (Well even in the best of wiring, difference in internal resistance of batteries even those from same manufacturers means with time they will go out of sync) This why I love FLA. Equalization helps alot in addressing this issues. For FLR, a battery balancer during initial installation stage is best.
|Re: Solar Energy, A Complement To FTA by Barezzi(m): 12:47pm On Apr 16|
Plenty on google...
|Re: Solar Energy, A Complement To FTA by earthrealm(m): 12:59pm On Apr 16|
so with battery balancer, and or desulphator/equalizer, series batteries will still go out of sync??..how.. why?
24v setups have limitations which require more funds to surpass.
on the lithuim battery setup, maybe some of us are off grid or something. technology is evolving, am fairly certain within 10yrs abetter form of battery/energy source will be discovered, and 1 is now stuck with an expensive antique, a lead acid battery system or agm if properly sized and managed can go 7yrs plus, georged1 setup is a case in point, so why reinvent the wheel.??
if i state my supercar/range rover allegory, some people will vex again
|Re: Solar Energy, A Complement To FTA by Barezzi(m): 1:19pm On Apr 16|
More like Supercar/Horse-cart...both will attempt to go the distance, but one go pass-out for road.
|Re: Solar Energy, A Complement To FTA by makavele: 1:38pm On Apr 16|
Let me chip in from behind the curtains..
I guess he mean't to say 100ah lithium is equivalent to 200ah lead-acid . .
Because while you can only take LA batts as far as 50% to stay in shape; you can take Li batts down to 0%.
But what he failed to understand is that it is cheaper . . buying 300ah LA batts vs 100ah Li batts . .
For now,the expensive price and little practical facts does not do justice to dumping the traditional lead batts.
The "exaggerated" 50,000 to 100,000 cycles for now is merely hypothesis arrived at with extrapolated data
The true test would be using them for 10 years and see how the hold up . .practically I mean
|Re: Solar Energy, A Complement To FTA by makavele: 1:43pm On Apr 16|
Then how would you handle current in excess of 200 Amps; for a super large battery bank
You want to get cremated before your time, brov ?
|Re: Solar Energy, A Complement To FTA by kiekie1: 2:20pm On Apr 16|
Nice point Sir!
|Re: Solar Energy, A Complement To FTA by GeorgeD1(m): 2:48pm On Apr 16|
thanks for the links. believe me, i read every one of them.
the first link dwelt more on comparing starter batteries to lithium. at a capacity of 1:3 that may be
understandable. however, the victron write-up spoke more to my practical scenario of agm vs lithium
and seems to make more sense.
interestingly, i see that the writer also came up with a price point difference of 3.48 times the price
of agm even at 80% dod (lithium) vs 50% dod (la).
verdict: from a cost perspective, lead acid (la) still carries the day.
|Re: Solar Energy, A Complement To FTA by Barezzi(m): 3:10pm On Apr 16|
Yes GeorgeD1, the cost is prohibitive at the moment. That's why i wanna sell one of my kidneys
|Re: Solar Energy, A Complement To FTA by JUO(m): 3:26pm On Apr 16|
|Re: Solar Energy, A Complement To FTA by DMerciful(m): 10:40pm On Apr 16|
200A? Na printing press? Most inverter users... What's their average load?
|Re: Solar Energy, A Complement To FTA by DMerciful(m): 10:41pm On Apr 16|
Comparing lead acid with lithium is like comparing kerosene stove with gas!
|Re: Solar Energy, A Complement To FTA by pranil(m): 12:03am On Apr 17|
Please have a look at this bluenova doc . While I do not fully agree to numbers they make some pretty strong points . -http://bluenova.co.za/wp-content/uploads/2016/02/BlueNova-Launch-Presentation-V2.pdf
Adjust Lead-Acid Ah rating for Depth of Discharge (LA= 50% and LiFePO4=100% )
2. Adjust Lead-Acid Ah rating for Discharge Efficiency (25% more losses than LiFeYPO4)
3. Adjust Lead Acid Ah rating for Adjust for Terminal Voltage (5% lower)
Ah (LiFeYPO4) = Ah (LA) x 50% x 75% x 95% = 36%
Sizing a LiFeYPO4 battery = 100 Ah lead acid = 50 Ah (50%) 37.5 Ah (80%) 35.6 Ah (95%)
|Re: Solar Energy, A Complement To FTA by nonoski: 12:19am On Apr 17|
So I finally finished my connection over the weekend and have been monitoring the results.
Here’s my story.
It will help a lot of people venturing into RE.
My setup for now is 12 panels rated 300watts (3600w) each in 3S4P connection.
I already had an inverter and 48v x 200Ah battery bank (Bluegate VRLA Batteries). The batteries are 13 months old.
Before powering my charge controller (Outback FlexMax 80) and connecting my ZHC equalizer on Saturday I decided to check the reading of the batteries
Battery 1 – 12.2v
Battery 2 – 12.2v
Battery 3 – 12.2v
Battery 4 – 10.2v
The inverter I have been using has a maximum charge voltage of 53.4v (13.35v per battery) and a maximum charging current of 11.4A.
It took me over 10 months before I realized the inverter was undercharging the batteries basically because we had PHED light for at least 21hrs a day throu out last till January this year when we now go weeks without having light. So the inverter neva really went beyond 50% DOD. Infact it was on this thread I learnt that 53.4v is not a good charge voltage.
From my little knowledge of batteries I already know most of those batteries are sulphocated and may need to be changed soonest.
Since I powered my Outback CC midday Saturday till today Monday I haven’t seen more than 6.2KWH which I consider quite poor for a 3.6kw setup. (Thoug there wasn’t any sunshine throu out Sunday in ph).
But today Monday was all sunny and that was when the CC recorded 6.3kwh which less than 45% efficiency rating of the panels.
The incoming Amps didn’t go beyond 20Amps. I am beginning to doubt the rated output of the solar panel coz I was expecting at least 65-70% efficiency. I will be doing a string by string test tomorrow and Wednesday just to be sure.
Now I bought the Inverter and the solar panels (early last year 2017) from a known solar dealer here in Port Harcourt who came highly recommended. He is always on radio talking about renewable energy, in my office he is one of the main contractor for solar installations.
After I noticed the inverter was charging at 53.4v I decided to engage him on the issue.
I was both amazed and disappointed coz the guy is both empty and unknowledgeable compared the folks here on Nairaland. After much question I deduced that he just went to China and shipped in lots of solar panels and inverters. He isn’t even aware his inverters undercharge batteries.
My advice to those who want to go into RE to do a lot of research and triple check anything they want to buy. Check for reviews for any product they want to buy to be sure.
Contact the guys here, there are far more knowledgeable that all these clowns masquerading as solar expert. I don’t blame anybody who refuses to go into RE coz its quite heart breaking spending millions and within a year or 18 months everything fails.
My Solution: (I am learning the hard way)
I will be changing my inverter to a mustpower 5kva inverter (30a charger)
I will gradually phase out all the batteries I’m currently using and increase it to 48v x 400Ah by July
If the solar panels are also found wanting they too will be phased out gradually before February next year.
My goal is to achieve at 75% freedom from PHEd and their nuisance.
|Re: Solar Energy, A Complement To FTA by makavele: 12:45am On Apr 17|
Somebody with 20 units of 200Ah 12V batteries . . . (where between 10 -20) is the norm for energy autonomy
How safe to run as 12V parallel ?
|Re: Solar Energy, A Complement To FTA by pranil(m): 1:01am On Apr 17|
makavele:My earlier long post on the issue was swallowed by the Nairaland gremlin and I got banned for 24 hours I wonder why?
But in general, comparing lithium on installed price is not correct . for that matter any energy producing device is not priced at purchase price but on LCOE ( Levelized cost of electricity ) essentially price per kWh ( for detail understanding with Nigeria context)
1. True cost of LCOE .pdf
2. what is LCOE ( BNEV)
in my own case, the LCOE of BYD came to 50 NGN/KWH while trojan 12 V came to 55 and trojan 2V came to 45 NGN/KWH
This was including the cost of additional bms, shipping, customs stec. - I posted a simplified excel sheet with zero discounting a while back for those who are interested.
for me, there were two very big incentives - the convenience of not having to babysit the battery ( my other setup has flooded lead acid) and superfast charging ( since I also use the Diesel generator to charge on extended grid failures in the night )
What is also to be factored is the reduction of required PV panels - Due to fast charging and higher efficiency and absence of periodic equalization you can get away with 20 to 30 % smaller array for the same KWH of usable capacity
please refer to attached pdf ( lead-acid batt efficiency)
quote " - zero SOC to 84% SOC the average overall battery charging efficiency is 91%, and that the incremental battery charging efficiency from 79%to 84% is only 55%. This is particularly significant in PV systems where the designer expects the batteries normally operate at SOC above 80%"
finally, the choice of technology depends on the usage pattern but in general, Lithium makes sense currently in the application of peak reduction or timeshift of energy use . as a pure storage lead-acid will be the king for a quite a while till alternate technologies catch up
p.s interesting side note to the debate - On Sunday I noticed that small generators ( 2.5 kw to 7 KW) sold by Games in Jabi, Abuja have been fitted with lithium batteries as starter battery instead of standard SMF battery - There cannot be a worse application in hot temperatures than a generator starter battery
|Re: Solar Energy, A Complement To FTA by kiekie1: 5:05am On Apr 17|
Good morning Nonoski,
How did you tackle the issue of the bluegate battery reading below 11v ? What is the name of solar panel & did you run brief individual test on solar panels before mounting them ? Was there marginal variations in the individual string readings in the combiner box? Are the panels shaded in anyway whilst operational ? Was mc4 connectors used ??
Ceteris paribus, you will surely enjoy your set up ! Cheer's
|Re: Solar Energy, A Complement To FTA by nonoski: 7:55am On Apr 17|
kiekie1:I changed the position of the battery and used the charge controller to carry out equalization at 60v for 2hrs plus I connected ZHC battery equalizer.
Since Saturday the battery bank that couldn't last 6hrs (usually goes of by 5am) now last more than 9hrs till sunrise (with more load). So for now I think I will manage them till the end of the month when I will start changing them in pairs.
I tested all 12panels and they had similar readings + or - 2v.
The 4 strings almost same reading + or - 0.2v (101v to be Precise)
But I don't have an Amp meter to know the exact amperage of strings coz on the CC it's shows less than 18amps while I'm expecting at least 30-36 amps.
Yes I used Mc4 connectors I bought from Amazon and kept running test to make sure all the connections were Ok.
Will test each string this morning when the sun is up
|Re: Solar Energy, A Complement To FTA by Wazari: 10:48am On Apr 17|
I find it incredible that you have been able to achieve an LCOE of N45 - N50. I have not seen anyone in Nigeria do lower than N80/kwh for a residential solar PV system with storage.
I looked at your old spreadsheet but it looks like you only accounted for the direct and associated costs of the battery, not the complete system. Am I mistaken? Please, I'm very interested in your figures to see how you arrived at N50.
|Re: Solar Energy, A Complement To FTA by NiyiOmoIyunade(m): 11:14am On Apr 17|
Since you have a combiner box, you can simply switch off all breakers for all PV strings and switch them ON one at a time and use the AMPS output reading at your CC screen to see what each string of 3 panels is putting out. That way you can see if any string is underperforming relative to the others - this is a cheap workaround for your lack of a DC clamp meter.
Be sure to have a sufficient constant house load ON and PHCN/Gen OFF at the time of testing so the panels are giving their maximum juice and of course do it when the batteries are drained and charging at bulk stage.
The extra backup hours you are getting is a result of proper charge voltage unwinding some of the sulphation your batteries have suffered and one possible reason why your solar output is low is because your real battery capacity is being limited by the one bad battery in the string.
Given 4 12v 200ah batteries in series to make 48v 200ah. If one of the batteries (the one reading 10.2v) has capacity reduced to 80ah for example then what you have is a 48v 80ah battery bank and this is how your batteries will behave under charge and discharge with the extra consequence that the 200ah batteries in the string will overcharge and boil out and slowly lose capacity just like the one bad one.
You really can't equalize mismatched capacity sealed batteries in series. All you will be doing is boiling the good batteries in the series string. Isolate the one bad battery and give it a proper charge and then assess its capacity.
|Re: Solar Energy, A Complement To FTA by earthrealm(m): 12:46pm On Apr 17|
yeah, equalizing sealed batteries is NO NO, agm you might get away with the error if tim frame was short..gel batts are unforgiving, they will be irreparably damaged.
your best bet is to isolate the bad batt and subject it to +0.4v on the bulk/absorb/float voltage settings, prefarablly using a charger with desulphation capabilities,connect i to a load and drain it, repeat same for like 2 cycles and observe
but if the battery gets really hot while doing this..the chances of success is pretty low, the batt has crossed the point of no return, best to discard and replace
|Re: Solar Energy, A Complement To FTA by nonoski: 1:49pm On Apr 17|
NiyiOmoIyunade:Thank you very much
I have already done the string by string isolation and notice one of the strings is faulty (maybe due to wiring) so I put off the breaker so for now it's just 3S3P.
The thing is there has been Phed light since Friday till now so the batteries haven't really been drained so I can really tell the output of the CC.
|Re: Solar Energy, A Complement To FTA by Oshomo12(m): 2:02pm On Apr 17|
I want to believe one of the reasons for you to go solar is to reduce what u consumed from PHCN. So during the peak hours of sunshine, just put off ur PHCN supply and check what ur system will give u.
|Re: Solar Energy, A Complement To FTA by earthrealm(m): 3:39pm On Apr 17|
another way of seeing what your array is capable of is running 2 acs or sumo +microwave for 10mins, that will take your bank off float to bulk, then turn on your array input to cc....still with the loads on
|Re: Solar Energy, A Complement To FTA by NiyiOmoIyunade(m): 4:08pm On Apr 17|
Oga Nonoski is still trying to build his faith in solar hence still clinging to Grid Power.
Small by small as faith grows you start to leave your changeover in neutral or pull the 'cutout' or trip off the Grid Meter's MCB and then you see that you can get by.
This is the true test of an offgrid solar system design - how long can you go with only the power from PV panels and batteries to run your house? How well can you go through bad weather and low yield days and still have power?
Your investment in Solar is already sunk anyways apart from your batteries which need periodic replacement - one might as well milk this solar power source for all it can yield
|Re: Solar Energy, A Complement To FTA by bigrovar(m): 4:08pm On Apr 17|
pranil:All this points to is that long term Lithium will eventually cost lesser than lead acid batteries.. However what this analysis misses out is the fact that Money Time Value overwhelmingly favours Lead acid. Lithium is only cheaper over a longer stretch of time. The initial cost is the biggest turnoff and why it is yet to be mainstream. The added fact that lithium is still a bleeding edge technology which is not yet as matured as LA is one more reason why time value does not favour it.. In the many years while Lithium is still paying for itself.. newer, better and cheaper iteration of lithium or energy storage device would have been released.
|Re: Solar Energy, A Complement To FTA by pranil(m): 6:12pm On Apr 17|
Yes, I was considering only battery the rest of the system is assumed to be same ( as I was just retrofitting an old system) but in lithium,case you can get away with smaller PV due to higher efficiency.
Also, other companies might give lower LCOE but I did not consider them as I had no access to purchase or manufacturer support to integrate with Victron
Please have a look at TESVOLT site where they back up 0.09 Euro ( 9 cents ) with a commercial guarantee
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