₦airaland Forum

anochuks08:
I am talking of battery connection. let's say a 24v inverter and the owner wants to connect up to 10, 20 or even more batteries in series n parallel to increase power, is there a maximum number of allowed parallel connection?

Brother, avoid parallel connections as much as you can. They always turn out to be not worth the trouble. The cost (In wiring, etc) of having a decent parallel connection to ensure each battery in the bank get equal amount of charge makes it not worth it. Also because you are dealing with very high amp getting breakers for the system is another hassle. Even when all said and done you manage to achieve a setup that ensures all the batteries get equal charge (not an easy fit) The internal chemistry of each bank would still make it so that each battery gets charged differently. The result is the bank would likely die before it's time.

Secondly the size of wiring you would require would be huge in other to avoid voltage loss. Lastly when a battery in the bank goes south, it would be hard to notice because the other batteries would cover for it. So if a battery goes bad and voltage drops to 10.5v no way of knowing this. (Unlike a series connection where the drop in voltage would force the bank nominal voltage down and can easily be spotted.

alternative:

As suggested, go for higher voltage. so instead of connecting 4 batteries in parallel for a 12 or 24v system. Go for a 48v system.

If you most use a 24v system and still require more power. Then your best bet are OPzV batteries. This batteries come in small voltage high Amp type. like 2v 500AH. they are available in Nigeria and are mostly used by telcos. 12 of them connected in series gives you a 24v 500AH system.

cheers

anidat77:
@ iLoveTheSun
thanks for the info man.....It really a scared me when I saw them looking different until I did some research and actually got them tested. Its not Sunpower though, I'll watch its performance as time goes on. Got me 4 panels to upgrade my old two 200Ah batteries / 24v inverter system.
Here's the label behind it and hey guys just received my Epever tracer controller today too.
I'm looking towards the pole mount options to mount the panels to a water tank stand (Diplomatic limitations on using the roof) hope I get good house of sunshine out of shades, hope you guys guide me through alternative mounting options.

With you guys all the way" Going green rocks"...

If the nominal voltage of your panel is 24v then your best bet is a series parallel connection. Beware of shading when mounting your panels. Make sure there are not structures that can cast shade on your panel. Also make sure your panel faces south.. and ensure it is grounded.

Trippledots:
1...mppt only helps to find the point of "maximum power" transfer and it supplies your battery at that point.this is simpy the point when the inout resistance equals the output resistance; perturbing and other methods are used to find that point in PV modules.
AC can effectively convert voltage to AMPS with the use of electromagnetic induction,but we are dealing with DC. except you can tell me how the mppt converts excess voltage to current tho...

2..concerning my "number 1"...you are right but partially. distance matters from panel to CC to battery. Wherever DC is carried with significant AMPs then distance becomes important. However, proper sizing of cables conducting the DC can reduce the ohmic losses.

PS: d issue of distance is one of the reasons AC is employed in national power distribution rather than DC.

You are over thinking this. Might want to do a simple Google search. Maximum power point tracking tracks tracks the power generated by your panel and uses the optimum value to charge your battery. Let's say I have 2 panels each at the following specifications
PMAX 240w
VOC 37.8
VMP 30.5
IMP 7.8

My battery bank is 24v. If I do a parallel connection. The VMP of my panel would be inadequate to properly charge my battery which requires at least 28.4v on regular charge and 30v on equalisation charge. Wiring loss, heat loss and general non standard condition would ensure that I never 30v from the panel to the controller.

My best bet is to connect in series. Series connection would give me about 60v VMP from my panels. More than enough voltage to charge my battery. However if I used a PWM controller. PWM would be unable to utilise all of my panel PMAX. It would only be able to use roughly half panel capacity. Other half is wasted.. because pwm does not have a DC to DC converter. It only takes about 28v required to charge battery and 7Amps.

An MPPT is a different beast. It will take the 60vmp coming from the panel and down convert to about 28v needed for my battery. The rest is converted to amps.. and added to the 7amps coming from my panels so in the end my battery gets about 28v 15-17amps on a decent day (plus or minus )

Of cause no conversion is 100% some energy is lost during the conversation stage but in all most mppt are 97% efficient. The mppt tracks your panel through out the day delivering the optimum charge to your battery based on panel PMAX which changes based on weather conditions.

One out of the numerous advantage of using MPPT is it saves on wiring. You spend less on wiring because you can string your panels in series to 3 times your battery nominal voltage (higher voltage means less resistance)

It also get the best out of panels whose nominal voltage is too low to effectively charge a battery. A good 12v panels should have a VMP of at least 18v anything less and you need an mppt otherwise u won't be able to efficiently charge your battery.

PWM are not useless. They are ideal for small installations where the battery nominal voltage is close to panel voltage. And cabling between panel and battery is very short. The relatively high power usage of an mppt might make it less ideal for such applications.

bigrovar:
am interested in this product, can it be used to set timer.. like auto turn off a device after a set time or threshold (say after consuming 500wh)?

for those interested in the device, it does have timer function but it can not be timed by watt threshold (unless one has access to the SDK and modify some parameters.)

pranil:
I found the broadlink platform quite good specially their power socket which keeps a history of the power use and current use for any appliance. Very Good to monitor fridge and AC

http://www.aliexpress.com/item/Broadlink-SP2-EU-Smart-Home-Wireless-Remote-Control-Electrical-Smart-Plugs-Sockets-By-app-control-switch/32655943437.html

am interested in this product, can it be used to set timer.. like auto turn off a device after a set time or threshold (say after consuming 500wh)?

kiekie1:
Recently offloaded solar panels ;
FLAMES 130w mono panels ......@ 40k
CSUN 200w mono panels ........@57k

MY HOME 150w poly panels........@40k
MY HOME 250w poly panels.......@70k "limited stock"
MY HOME 300w poly panels........@75k "limited stock"

I directed a friend to call you for 2 of the 200w. He is based in lagos. He wants to know sizes and price for dc breakers?

Use to use Mobile one 5w-30 but tough times for me to use Shell which is actually recommended for my Hyundai.

kiekie1:
So funny ! When you visit Alaba market this days , you meet so many urchins parading themselves as solar / inverter installers .. I had to briefly discuss with one of them few months ago as I noticed him arguing with all authority that he has been installing for so many years , I asked him to briefly explain to me what 145 / 150VDC max means on most of the MPPT in market? He replied "he dosnt know".. I simply wonder what that kinda person will do on peoples roofs or deckings with i.e 12 units of 250w panels and 60a mppt to charge a 48v flooded battery bank with maybe 20k installation cost without solar PV rack cost inclusive ..

Your own beta Na. Met some guy who came to buy close to 10 300w panels in a store in Abuja. I wanted to know the specs of the panels so I asked him what their VMP was... Blank stare.. he looked at me like I spoke German he blinked twice. I asked again and he didn't know what a VMP was. I just smh at the poor dude who by now has already been shafted of his money.

[quote author=Dreamflyin post=47990882][/quote]the first thing that came my mind even before I saw the picture was.. charge controller is effed.. seeing the picture u posted just confirm my suspicions. My preliminary prognosis is those batteries died of being under charged for a prolonged period if time. Those controllers are pwm and there is no way they would be able to fully utilise the full potential of your panels...

This is just a preliminary prognosis. Solar has so many variables on what can go wrong which is why it is good to do proper research before you embark on it. Unfortunately lots of quacks out there burning people's hard-earned money on phoney installation.

What's the way forward. You need to supply the following information. Type of panel and their specs particularly the VMP.. What is the voltage of your inverter. 12 or 24v. How are the batteries connected series .. parallel or series parallel. Distance between your panel and your charge controller..

Without the above stated information it would be impossible to help you out.

Brother all hope is not lost Sha. Everyone makes one mistake or the other in their installation before learning .. the inverter and panel seem good. Might just need to change configuration and probably some equipment.. that CC for example has to go.

obimind:
@Earthrealm, thanks bro...currently I'm using AGM batteries and am about purchasing new sets of batteries. My installer keeps advising me to go for GEL batteries which I'm trying to get more info to avoid regretting my decision at the end of the day. I'm so grateful Sir.

Go for agm batteries. Gel beside the can be very pecky when it comes to how it likes to be charged. AGM is a bit more rugged and can take more charge current in bulk state than any of the lead acid batteries flooded or Gel. Varta and Luminous are good agm batteries.

earthrealm:
luminous smf batt , i think is average, not super per se.....mine crapped out in the 3rd yr, diminished performance etc...i opened them up and topped up with about 30ml of AC water to each cell, got desulphators and hooked on them, this appeared to have revived them bit, as i was about buying new batts, but have postponed the purchase for now, since they are doing fairly ok now.

2 years is not bad Sha.. considering the price. What was the average DOD for the 3 years.

as per fla, which wahala are they giving you?...am running mecury tubulars, got them around march.....topped them up with water mid july...as i noticed some cells were going low....i bet they would hv lasted 1 more month before getting to the red zone..as per electrolyte level, so i can safely dedude that they need watering every 4 to 5months....which isnt bad.

interested in the wahala yours are giving you

Not performance wahala o. They are still running ok performance wise. Just got home now and forgot to flip on the solar breaker after I turned it off last night after a thunderstorm. This allowed the battery to rest for over 8 hours and my voltage when I got back from work is 25.7 6 which is not bad. The wahala is FLA is like a fine city babe.. you gasto give her attention otherwise u no go enjoy am. You most not over charge it, it most not be installed in a place without proper ventilation, u have to make sure you equalise, get hydrometer to always check SG level haba. I don turn chemistry student finish. SMF no too get all this wahala. But I hope the Mercury Tubular is worth it Sha. If it can serve me for 3 years. I would be very happy.

chris81964:
Wow. Thank you. I am humbled @bigrovar.
I was a Ubuntu fan years ago. I had installed it on my server and desktops in my home office. My sons liked it. The middle one works at the IT department of a local university. It paid off. The baby who goes to the university next year wants to major in computer science.
Sorry to go off topic.

wow that's awesome won't be the first I am hearing such testimony. My current project is to use the Raspberry pi to talk to the Tracer controller using a Tracer python module. It will then upload data from the tracer to an online server via FTP. This would allow controller real time data available online.

earthrealm:
@pranil and tivta , i understand perfectly what he wrote or that the nickel iron battery is far superior to the other batts we have around.....
am just airing my mind/being practical/realistic.

few people can afford the battery, i myself will not buy it. i would rather buy 5 or 6 trojans with the money and replace every 10 to 15 yrs...than buy a single nickel iron battery.............that i will never change till 30yrs.

The future is Lithium and we can expect the auto industries to help bring it to mainstream in terms of affordability they same way auto industry helped popularized the Lead Acid batteries.

i have a luminous smf battery, and its going on 4yrs now....still doing fairly ok, with several tweaks i carried out, i see the battery getting to 6 or 7yrs.....powers a fridge for 8hrs daily, and lights/tv/fans as needed

I have already heard good things said about the Luminous SMF batteries. I think they are AGM (No?) It is what I always recommend to solar newbies as a good balance between prices and quality. If I gad to redo anything with my setup. I would strongly consider them as I am finding maintaining FLA to have quite a bit of wahala.

hybrid inverters are the future...i see them getting bettter with time, with data logging capabilities

Data logging is actually what interest me most about them. ability to have a system to log power generation and consumption.

pranil:
If you want to save on NEPA most of the new hybdrid inverters have a abttrery or solar mode where they take from solar before switching to Grid

I have always found hybrid to be fascinating however my Unix background has wired the concept of always going for tools that do one thing but does it well. I feel though that the future of off grid might lie with hybrid inverters the integration makes more sense.

chris81964:
I am on Twitter personally @chris81964 and as a business @atlanticwastepw.
Thank you for thinking enough of me to recommend. Subscribe to me on YouTube. We have over 60 videos. I did most of them in Nigeria.

Not sure am subscribed but seen most of your videos. It inspired me to make mine.

Btw Chris. Are you on Twitter ? Some recommendations I want to send your way. Some Lagos based followers are interested in solar

chris81964:
After I subscribed to your Youtube page na him you wan fight me. Okay oh nothing spoil. (I hope you posses a sense of humour)
You do reflect a cost bias. Give an opinion just like you did in your video and let the people make a determination as to if it makes financial sense to them.
I commend you for the steps you took and 95% of the people reading these exchanges will not pull the trigger. In addition to hard costs do we look at the soft and more punishing longer term cost of running fossil fuel based energy sources?
Just tell the story and let people make a decision either way if it makes financial sense to them or not.
And with a name like bigrovar I am sure your pocket matches your name. My company installs solar and if we sell based on upfront cost we will be out of business.

Solar power involves compromises. Yes on extended cloudy days you turn everything off or turn on a generator to charge your batteries. You have to do more planning during the rainy season than you would with the grid or generator.

However would I give it up. The answer is no. I place a very high value on having electricity 24/7.

We agree. Sometimes written words do not convey communication efficiently. Anyway thanks for the feedback

chris81964:
The size of your pocket should not determine another persons choice. Solar is very mainstream in the US, Europe and China. Go to the middle east and it is widely adopted. The size of your pocket should not be a determinant to what another should do. A friend of mine has a factory close to my home with 665 KW of solar installed. It made sense for his business.
I changed my light bulbs, I purchased an energy efficient freezer. These are practices that are common in the West where people pay the real cost of electricity unlike the subsidized values we pay in Nigeria. People who are not into energy efficiency and with money to burn will pay a higher premium to get solar power. Lead acid batteries come in different flavors. The Rolls Surette, Trojan IND or L16, Hoppecke are high end batteries designed to give you a minimum of 7 years and up to 15 years with proper maintenance.

Please brother. Point to where I talked about the size of my pocket. Do you know the size of my pocket? Who is talking about pocket size. Point to me where I suggested or insinuated that installation should be done based on my pocket? I talked about installation having to be economically viable to make sense. Economic viability of a project is unique to each project and what individual can afford. I spent more time advising on how to make a system efficient so that the consumer spends less on generation which is pretty much what everyone here agrees on. Europe, China and middle East are all middle income countries what applies there don't apply here. Less than 2 million Nigerians earn more than 250k a month. To that extent Nigerians are generally more sensitive to cost. I am not a installer I don't sell solar product I feel no conflict of interest when I advise people to take time to make their system efficient before going solar. I shared my experience with solar here for anyone who may not be able to fork out the start up cost to take time and plan over a period buying that they need piecemeal. But that is a choice if anyone has the money and it makes sense by all means.
I live in Abuja where someone spent over 30 million on solar for his house. Having a well efficient designed system is not about throwing money. It's takes serious planning that including consumption efficiency, system design all to ensure the end user gets the optimum value for his money. Your friend made the investment because it made sense for his business. He pulled the trigger after making some maths to see the cost analysis favoured him going solar. How is That different from what am advocating.

CoolKizzy:
Thanks bro, I spent roughly 384,000, from 1st April to 10 July on diesel, fuel and maintenance of generators, plus they are depreciating. This is exclusive of the monthly outrageous EEDC bills. That was what prompted my search for a cost friendly alternative.

Now the plan is to go solar remove every heavy machinery and use them only for bulbs, Clippers and TV.
Then still be connected to the discos and use it to power a. C when power is available, this will reduce our standard but I think it's necessary to survive first. I'll then purchase a smaller gen for my heating equipments which are not used more than an hour cumulative per day.

That's the way to go. Take out the heavy machine and see how to can get more efficiency out of your current appliances without breaking the bank. You might want to consider DC powered rechargeable clippers if u think it will work for u. Maybe buy one and see how it goes
http://s.aliexpress.com/rUfMRzUz When u switch to led lights u will find out cost of solar would drop considerably because it is cheaper to conserve energy than to generate it. Sweet thing about renewable is u can use it on demand. And u take just want you need. Unlike powering a whole 5kva gen just because u want to run a 50 to 100w clipper. Further more. A well sized system would allow you even generate all your concurrent needs when the sun it out till about 1600 hours on a good Sunny day so all you will be using will be free energy from the sun. Also when you turn on your gen for the heavy stuff. It will also be charging the battery while it is on adding one more layer of efficiency to the system. Just remember it is cheaper to conserve energy than to generate it.

chris81964:
Sounds like something Fashola will say. Solar is an option that should be on the table for everyone. With proper planning you can make it work for you. Invest in the proper equipment upfront.
Battery technology has advanced beyond the stone age. We have Lithium Phosphate battery, Saltwater batteries and the Iron Edison style batteries that have in excess of 3000 cycles at 90%.
I currently use flooded batteries that have a duty cycle of 1500 at 50%. When they eventually die I will replace them with one of the batteries that I mentioned.
I don't have AC, however I have fans, TV, A freezer that runs 24 hours a day, a refrigerator that runs from 8 am to 5 pm daily. I have not used a generator in 2 years. Because of the unusual rainy and cloudy weather that we are experiencing in Lagos I will purchase a generator. I intend to run it for 4 hours a week to compensate for the deficit in production from my 2 kw in panels.

I do not disagree with anything you have said. Only thing I added was for him to look at the economics of solar to consider if it is worth it. This was in response to the brother that gave a ball park figure of what it could cost to implement solar based on the energy figure he gave.

Go on Nigerian Twitter I am one of the biggest promoter of RE and solar energy. However RE should not just be about power generation it is about economy and conservation of energy. All three most go together to be viable. No point going solar if in your case the economics and opportunity cost won't favour your business. Especially if your business is AC and heavy machine intensive.. the start up cost might be such that it would be difficult to recoup back before your first financial maintenance usually the battery. Even if you could. That up front might just be too much to release one time.

For me I planned my system over a 12 months period.. making adjustments and creating efficiencies in areas like ensuring my house had natural cooling even during hot season.. this involved choosing what part of the city I site my house, type of window, where my window is facing etc. I took 600w off my power needs by outsourcing security and external lighting to external solar security motion sensor lights that cost less than $60. Invested in energy saving bulbs from Philips highest of which is 11w but most are 8 and 5w. Got an LED 43 TV that uses 35w. A freezer that can run even with 800w inverter (startup surge and all) all this I got 12 months before buying my first solar equipment.

And when I started buying, it was in piecemeal over a period of 10 months. 2 240w panel, charge controller, inverter, breakers, mc4 connectors, crimpers , wire lugs etc.. last thing I got was the battery which I got in may this year. System has since been live. My earlier activity at conserving energy has been a success.. my room is always chilled never used the AC there once and it has no fan. Just added a 3rd panel 220w panel to put my string at 660w. The result is here http://twitter.com/bigbrovar/status/757182083127185409?s=09

Still approach to solar should be from an economic point of view in my opinion. My investment made sense because I was spending close to 480k yearly on generator hence investing 450k on a solar setup with a battery rated at 1200 cycles at 80% dod (which is cycled daily at 35% dod) is a no brainier for me. Everytime I think of the money spent.. I remember the cost of generator and I have no regrets.

Still I will always recommend that people do their maths to see if the economics favours going solar. As much progress has been made. Solar is still not affordable. Battery tech is still background. Over 90% of off grid solar rely on Lead acid batteries which are highly inefficient when it comes to charging and discharging. New technologies in batteries are not mainstream yet and are very very expensive. When I can purchase a power wall battery for 150k that can will store at least 5200wh of energy and I can totally discharge it and replenish without worrying about dod. Then we would no that we have arrived. For now. Alternative energy is still alternative. It requires separate set of thinking outside how you approach grid power.

CoolKizzy:
Thanks chief, I can quickly change the bulbs, but the air conditioners will need proper planning and savings. Is there a way I can run it with the current a. C?

By brother. Look at the economics and see if it pays and makes economic sense in your case to go solar. Solar sweet but the technically is not there yet. It is still too expensive especially with very high energy consumption. All those adjustments cost money.. money which can be reinvested in the business. Now here is what I did, maybe it will work for you. Calculate how much your spend on generator maintenance fuel repairs and all. x 12 (representing 12 months) should give u roughly how much u spend on fuel. Let's say u want a solar setup hat pays for itself in two years. U can further multiply the yearly figure by 2. The final result if it is close or more than 10m then you can consider solar. If it is less. Then the economics will not favour you. Panels are coming down in price but there are still not there yet. Battery technology is still stone age and improvements are slow and very expensive. One day renewable will get there .

anochuks08:
Help me chk ds diagram of my battery bank of 12 batteries.

Regards

From your diagram and IMHO. Some not all the batteries will get equal charge. Some will gets more charge and do more work the others... Eventually this would create divergence in battery capacity and result some batteries dying before others.

The rule is . Use proper size wire and all wires going to the Positive and Negative Combiners Must be of " EQUAL LENGTHS" Including any wires tying 2 batteries in series. That way you get even battery charging and equal power draw across the battery bank.
This is a product of deep research. It will make your batteries have a long and reared life span.

CoolKizzy:
Hello house, I calculated the total watts rating of a the electronics in my salon and I arrived at 14523, but don't think I can be using more than 10000 watts simultaneously else during peak seasons like Xmas, is it possible to go solar with such gigantic energy requirement?

How did you arrive at those figures if I may ask.

2 hours each. Which seems to be the generally accepted number based on most documentations. A really smart charger like the Midnight's and co should be able to auto detect the absorption time based on algorithms the determine it from battery internal resistance. But 2 hours should be fine.

* To equalise properly. You are suppose to start when battery is full. And continue and continue to check the gravity level of your electrolyte till u stop noticing an increase and all cells are pretty much of equal or close to equal gravity* but ain't no body gat time for that

DUNKA:
Goodday what settings i.e bulk,float,absorb and equalize are you using for your tubular batteries. Also advise the times for absorb and eqaulization.

Based on my email exchange with sukam support center (as I could not find any information whatsoever about the charging profile of the Mercury Tubular) I used what I found relating to other Tubular batteries like Sukam and Luminous:

Floating = 27.3
Absorb = 14.5 ( I was told by sukam support that absob voltage for their tubular is 14.4 - and that was what I saw on pretty much every documentation on indians tubular batteries, however made the decision to use 14.5 since my controller does not have a separate voltage sensing cable)
Equalisation= 15.5

femarse:
pls I want to lay my hands on Linux which one should I go for Ubuntu ? Fedora? Linux mint ? beside am planning on dual booting it with window system spec is Intel celeron n2830 500g ROM 2g RAM thanks

I would recommend you use xfce flavour of Ubuntu which is called xububtu. I would have recommended Linux mint but their recent security lapses have made me lost faith in the project. Xububtu will perform wonders on that hardware of yours. It is a light weight desktop aimed at lower power computer that you are running. Fedora for me has always been considered a testing ground for red hat so unless it is for learning ( in which case use cent OS) I never recommend fedora.

mank1234:
Nice observation. Truly the final decision lies with the user.

Equally important but often ignored is the issue of hour rate. Battery life are also rated in hour rate (for instance a 200AH battery might be rated so at 20hr rate but 160AH at 5hr rate). The implication of this is that the faster the rate of discharging, the lower the capacity you'll get from your battery. To make it clearer, if you cycle your battery once a day at 20hr rate (drawing 10A) it will last more years than cycling once a day at 5hr rate (40A).

My mentor is still using his 4 cyberpower batteries 10+ years going even though he occasionally reaches 80% DOD. His secret: size your battery bank such that charging and discharging current is between 10-20A per battery, use intelligent charger that regulates charging voltage, can equalize battery and is temperature compensated, use intelligent inverter that cuts off at at least 80% DOD, if possible placed your battery in environment of 25 degree Celsius, don't leave your battery in a discharged state for more than 12 hrs. He connected his battery in grid format rather than series/parallel with the supply to battery from the charger NOT connected to only one battery. According to him he said that arrangement ensures all batteries sees near equal current and voltage.

Right on the money bro. This is why I discharge my battery at c40 though they are rated 220ah at c20. My discharge rate is usually less than 4ah and occasionally around 6ah when I have my freezer on (it's why I decided to only run the freezer at night when all load beside the fan is on and the freezer stays on for about 5 hours) In total my average daily circle are 25% to 35% dod. ( I use a watt meter with a current shunt placed between inverter and battery to accurately note battery discharge rate and total amount of discharge)

Despite powering 95% of electrical needs I have never used close to 1500w of energy in a day. My max is 1350w which is 25% dod of my battery bank. (Considering am using the battery at close to c30 the actual dod will be lower than 25%). This is where efficiency plays a big role. Efficient consumption ensures you use less at a laser discharge rate. In the end my 620w panels can easily replace back what is used even on a cloudy day. I always tell people it is cheaper to conserve energy than to generate it.

obimind:
@ all, deep cycle batteries and gel batteries which one is better in terms of being rugged and surviving deep discharge over time? Pls opinions are highly welcome. Thanks!

Deep cycle is a generic name for batteries that are designed to be (well) deeply cycled (cycle being a discharge and charge) as against automobile batteries which are not design for deep discharge.

Gel, AGM and Flooded acid batteries are all types of deep cycle batteries. The type depends on your use and how you designed your system and your peculiarities.

for new users with a large family and little space, I often recommed AGM batteries for the following reasons:

The are pretty much sealed and maintenance free, which means they require no water topping, little worry about gaseous discharge.. no worries about using hydrometers or acid spill.. They can also take quick charge, AGM batteries can take as much as 40% of their current capacity hence they are great for using with high charge capacity inverters and large solar array.

The down side of AGM is that they mostly don't like heat, and they have relatively lower cycle time compared to flooded acid batteries. Most AGM batteries sold in Nigerian market have as little as 500 cycles when used at 50 depth of discharge. If a cycle is a day of use, that is roughly a year and half. Some high end AGM can do as much as 1000 cycles at 50% dod but that will cost u.

FLA requires lots of baby sitting, you have to ensure acid dont spill, always make sure it is has right water level, always good to have a hydrometer close by to check the electrolyte and acid levels, They usually don't like fast charging (not more than 13% of capacity) if you charge more than the recommended rate they will gass and release hydrogen which if kept in an unventilated space can lead to a huge nice cute explosion..and when no explosion happen will cause the battery to die before it should.

the upside for FLA and why I choose it is they can give u very high dod. The brand am using (Mercury tubular battery) is rated at 1250 cycles and 80% dod. (I use it at less than 30% dod) for me that is what wins it. batteries are the only component in an offgrid system that requires regular replacement. so the longer your battery can last the better and most cost effective your system would be. So if you are not scared of a big nice explosion and u fancy waking while wife is asleep to check the gravity level of batteries.. and don't mind equalizing your batteries for 2 hours and sit to monitor that all goes well, if you have a well ventilated space then I would recommend flooded lead acid.

for AGM if you can get Luminous batteries it is a good affordable agm battery.. the more expensive ones like Ritar are also good.

for FLA, Trojan is the king of the hill, US battery is also top dog but if they are beyond your reach, Luminous and Mercury tubular batteries are also good.

blazeup:
gentlemen, it is right to connect my inverter DC inlet to the Load connection point of my MPPT charge controller ?
a colleague in the Office (a certified EE) has insisted that is the correct method of connecting both the inverter, solar and Disco power as it would enable the charge controller serve as a switch and as well regulate the current at which i charge my batteries.

that this : Solar PV to the solar PV input on the CC as usual, Batteries would be connected to the Battery input on the CC as usual, inverter DC cables would be connected to the Loads outlet of the CC .while the AC inlet of the inverter for charging would be connected and powered on.
His point been that the CC would switch between DC sources for charging the batteries as well regulate the SOC of the batteries to my preferred cut off point.
(solar to cc, battery to cc, inverter dc to cc loads, inverter AC input to AC mains for charging, inverter AC outlet to my desired inverter powered devices) vs ( solar pv to cc, battery to cc, Inverter DC to batteries, and the inverter AC IO would be same). Can the CC load point also serve as a DC input to the CC to charge the batteries as well ? the Charge controller here is an EPsolar 40 A.

please comment.

You certified EE friend is in need of urgent upgrade. The load side of a charge controller is not meant for running powerful load (the kind an inverter exert on your batteries) the load generally meant for small dc loads like lighting systems (some people use their cc to power their security lighting points as such can use the load aspect to make turning on of security lights automatic) You can also use the load aspect to design a low voltage disconnect setup, using a DC solid state relay with an AC disconnect (that's another story) Anyway on no condition are you suppose to connect your inverter to it. Check the connection schematics of any cc and you none would you see it where inverter is connected to the cc.. in fact you are always warned never to try it or you risk turning your cc into expensive metal.

DMerciful:
Let's not go to the extreme here. The op said he can get up to 6hours currently from the batteries but wants to buy more meaning the batteries are not that bad! You make it seems as if we are talking about a battery that is behaving like a capacitor .

Brother, u to do more research on this. You don't mix weak batteries with stronger ones. Don't matter is the battery ain't dead has long has the internal resistance are not the same don't mix them. In fact it is not recommended to mix new batteries in parallel (unless you have no choice ) parallel connection can already be inefficient as is than to then be mixing old and new batteries together. Making it series parallel won't solve the problem of the weaker batteries dragging down the healthier ones.

The op needs to do his load audit. Other wise what became of the old batteries will after the new. Batteries that can't serve you for 3 years defeats the cost savings of using inverter or going solar.

DMerciful:
Connect the old batteries in 1 string of 24v. Connect the new batteries in another string of 24v. Then parallel these 2 strings to have 24v, 400ah. Then connect to the inverter. This way the inverter charges them same time and saves you the extra work of manually switch to charge. Also because the new ones are stronger, they bear much of the load as it is more difficult for their terminal potential to drop due to load hence they do more work. They old ones won't load the new ones. Its just like a trailer with many tyres, the ones that are more inflated will carry more of the load. Only disadvantage is that it gives you false belief that you have 4 batteries when you have 2.7 batteries per se

with all due respect oga Dmerciful, nothing will kill is battery more. Mixing old (weak) batteries with new one is never advisable not with any connection string.. especially when it is a parallel connection. that is just a no no.

1- Parallel connection are to be avoiding even in the best of conditions its always better to thrive for higher voltage than then to achieve greater current via parallel connection. The problems lies with how hard it is to get the batteries in a parallel setup to having equal charge where you use a bus bar (more money) and ensure the wiring to the batteries are equal, since you can not determine internal resistance of each batteries.. one battery would still get more charge than the other. This would allow

1 the battery with least charge become a load on the stronger battery thus bringing the whole battery setup down.
2. Stronger battery gets over charged during the charging process has it gets full before the other battery in the setup. It will get over charged and over worked while the other batteries get undercharged. In the end the whole bank will fail in less time than estimated.

2. You are mixing strong battery with old one. and putting it in a parallel connection. It is just not the optimal and efficient way to go.

My advise would be that OP first do an audit of his consumption and load. The first thing u do before throwing money at a problem is find out actually what the problem is. In this case the problem is you want regular power. First thing is to do an energy audit. You will find out energy audit is the cheapest activity required when you take the step to solar or inverter.. it is the cheapest and the one that is most likely to save you the most money.

Calculate the load you want to put on your inverter, and how many hours you want them on per day.
e.g I want to have my tv on my inverter. My tv is 70w (you can read the tv power rating or better still buy a watt meter - less than 10k on konga -) and I need it to run for 10 hours

70 * 10 = 700wh

Fan 50w, runs for 10 hours = 500w

in total 700+500 = 1200wh.

in this example 1200wh is what you require from your system (this is just an example) from this figure you will determine how much battery you need.

if you are running a 24v system (which is more efficient.. higher the voltage more efficient) you will divide 1200 by 24

1200/24= 50

50AH is the amount u need. if that is all the load you require, then you can buy a 100 or 150AH battery. this would ensure that you daily use is between the recommended 50% or less depth of discharge to ensure your battery last long and allows you recoup your investment.

Doing an audit also allows you know how much panel u would require to keep your battery at full charge daily because it would make you know how much energy you need to produce to replace what is used everyday.

my 2 cents

durodee:
http://www.solarinsure.com/protect-your-solar-power-system-from-lightning

https://www.backwoodshome.com/articles2/images/yago116-5.gif

You can see from the above diagram that it is indicated that the negative from the battery should also be grounded. so I guess one has to research more into this to be sure.
that link is very enlightening (no puns intended) I grounded just the metal frame of my panels before, but I would proceed to get ground copper wire and ground each panel together and connect the output to my ground pole. Thanks