Dejavus

That's marketing drivel. It really depends on what you compare it to. If you compare it to a good grid-tie inverter like an SMA or a Fronius... no ways is that only going to last 5 years. Those things come with 12 year factory warranties (costs a little extra to extend it that far). Conversely, the micro-inverter lives in a very hostile environment (right below the hot PV module), so logically, all other things being equal and all,  I would expect the micro-inverter to fail earlier than the equivalent string inverter.
But... with that said... if you engineer it properly, they do work well. Enphase is (far as I can tell) the market leaders in this space, and they have only been around since 2006.
Not without using another battery inverter. Eg you can use a Victron Multiplus, and if you install it correctly the power from the microinverters will be used to charge the battery. Most micro-inverters can't be used if the grid is down, not even with a backup inverter such as the Multiplus, because they don't support frequency shifting. Again, the Fronius or the SMA works perfectly in such a setup.
Watch the Victron ESS webinar, but where they show the Fronius, envision many little micro-inverters in its place. Micro-inverters cannot be installed on the output of a Multi because of the lack of frequency shifting support, as mentioned, but otherwise it's pretty similar.

Clear skies and cold air yesterday had my system peaking at nearly 18kW from the 16.3kW of PV. The output on the right in the image is per phase on a 3 phase system.

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This ca
This can get technical, as you need to conduct lightning tests. 
But, basically, put a ground spike in the ground and run an earth cable on the mounting structure and make sure it touches every panel as well. Lighting will take the shortest path possible. It gets technical when you need todo an earth continuity test to make sure that the earth spike is earthed properly. sometimes you need to go deep, 2m+ and sometimes you need to put a couple spikes in the ground. Every building is different, and areas have different conductivity as well. 
For the Lightning arrestor, you can either go cheap and install a Class 2 "surge arrestor, they're about R900. Or you can do the right thing and install a "Class 1 & 2" lighting + surge protector. They're rather expensive though - R4.5k+ 
http://za.rs-online.com/web/p/surge-suppressor-units/7838736/
 
Here's some more info on the topic:
https://www.dehn-international.com/pdbRes/DE_EN_Web/671/404725/Artikelnummer-pdf/404734/900065.pdf
http://www.ee.co.za/article/lightning-surge-protection-rooftop-pv-systems.html
http://www.surgetek.co.za/files/saltek_full_pv_catalogue.pdf
http://www.sinetech.co.za/select-surge-protection.shtml

It is always preferable to have a battery bank made up of a single string of batteries over a battery bank made of parallel batteries. If you do have multiple strings make sure the cables connecting the batteries of a individual string my be the same length for every string. Parallel battery strings are parallel pathways for current and you want the resistance and therefore current flow to be even between the strings. Your brother (boet in South African slang), the electrical engineer,  should be able to explain or look at information on the web. Each string needs to be connected to low resistance busbars and the inverter connected to the bus bars.

It may be a good idea to get some loose MC4 connectors from the same supplier that you get the combiner box or MC4 Y connectors from since sometimes different makes of MC4 connectors do not fit into one another. You don't want to find out in Nigeria that all you kit does not clip together as it should.

Where are you? I can send you MC4's and fuses. 
12A work very nicely in this case. 

HI Dejavus yes you could just swop out. 10 A might also work but you may get nuisance blowing of fuses on hot days.

Yes on certain days you might see more, still you cant use Voc voltage in the calculation. This is the voltage the panels give with nothing connected.
http://www.bonanzatech.co.za/index.php?id_product=7845&controller=product
Not even for this retail price? R7800incl VAT

I would connect your panels in two strings of 3. You will have a higher voltage but well within the specs for the Axpert plus. At higher voltages your cable losses will be kept to a minimum. Remember fuse your individual strings using a combiner box or MC4 Y connectors. Since you want to add more panels at a later stage I would go with a combiner box with 12A solar fuses.
Good luck with the install and we would like to see photos when you're done.

Agreed. And add what you use during the day to your PV system. We use more power during the day than at night, often 4x more. So our PV system is 2.5x what the battery bank can hold, works out fine at this stage, but we're short on energy, on cloudy days. I could add another 4 panels to compensate but don't have the roof space for it, close to the existing battery bank 

A 48V system would be much more efficient as a 12V or 24V, but if he only needs a couple hundred watt it should be fine?

More batteries doesn't necessarily mean more problems. If you're looking at using flooded batteries, you'll either use 2V or 6V cells in any case. I have 16x 6V batteries in my bank, on 48V system
Don't put the fridge on a timer, been there, done that, lost enough food to be content with 100W/hr during the night  As long as the fridge is in a cool place so it doesn't operate too much at night. And new fridges consume a lot less power than older ones. 

He said a fridge and freezer also. For this I would still say 48v as I take my bank down to 80-85% (48v 225AH bank) running basically the same equipment every night

Keep in mind, on a 12V system you need thicker cables to carry the same joules (i.e. Watt = Volt * Amp). To run a 1000W load, as example, off 12V you need 83A! It's only 42A over 24V. Then as your batteries are charged you need a few Ampere less, and a few more as the batteries run flat, i.e. 1000W = 90A / 11V or 45A/22V. 
Then, the more Ampere you withdraw from the battery the quicker it drains, not not linearly. Look at Pheukert's law. Simply put, the less strain you put on your batteries, the longer they will last and the longer they will run. 
On your questions: 
 
1. Flooded batteries need maintenance, yes, but if you are up to it (or, rather, if your parents are prepared to follow the maintenance procedures), they could easily outlast any battery for years to come. And you will gain back your investment after a few years. 
2. If there's no eskom backup, not really. Perpahs you could use the dry contacts to switch off a contactor in the DB board, and thus cutting the power off. 
3.It all depends on you / your budget / your backup needs. 2 x 12V/200Ah  = 24V/200Ah. 4x 12V/100Ah = 24V/200Ah. 4x 12V/200Ah = 24v/400Ah. More batteries equate using more cable, and could lead to more failure as well. If you need 4+ batteries, make sure they're from the same batch / age. Don't mix old and new batteries.
4. Yup. It's automatic Most inverter brands have this option. IF you have this option, you don't need to worry about Point #2, unless there's frequent power failures at night and your battery bank is too small to cope with the load. 
 
 
 

Sigh.
 
Where do I start probably first by thanking @TTT and @Plonkster for the time spent replying to my post.
I would very much love to go the Victron way however I have had to shell out on some less power  hungry electrical equipment in preparation for this project namely a new TV, previous one was 200W old sharp from 2007 to a 55W Sony, same goes for fridge freezer and fans hence my budget has depreciated to about 2K absolute maximum.
I thought of buying directly from the UK however the added cost of shipping has made it not a very good option plus warranty might be an issue if needed.
Hence my decision to go for the axpert plus my brother who is an eletcrical engineer can be summoned if required, he also currently uses a Gen/Grid battery powered solution himself. 
Aside of this project, I am also in the planning phase for a poultry farm which I intend to be completely an off grid solution.
 
 

Official way, for now, is to buy the ccgx for monitoring. That's another 350 Euro. I tend to agree that if I was on the right side of the exchange rate, I'd go Victron, but I have to temper my fanboyness a bit.
You're right in second paragraph though. Start with needs analysis. Then decide if a smaller 24v system would do. If yes, consider the 3kva multiplus or even the 2kva compact. Look what after sales service is like in that country. I don't know Nigeria at all but I know Victron has some penetration in Africa, so just maybe that makes the difference :-
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Fwiw, my 1.6kva compact with a 200ah 24v battery and 900w solar works very well to keep the fridge and freezer powered and for general backup, and in an extreme case I would be able to survive... if there is sun. Based on that, in tropical Nigeria, it sounds like your plan will work.
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Hi All,­
 ­
I came across this forum by accident and ­it seems to be the best accident that has­ ever happened to me. The information I h­ave read on this forum in the last few da­ys has surpased everything I have read in­ the last 4 weeks!
 ­
I live in the UK but my parents’ lives in­ Nigeria and due to the erratic power sup­ply I am in the process of installing a P­V/Inverter battery to make their lives ea­sier to require as little maintainance as­ possible.
 ­
I have read so much in the last One month­ and have decided to settle down to the f­ollowing:
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1 Axpert 3KVA Plus Hybrid  Inverter­
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4 x US 2000 XC2 Flooded Lead-Acid 6V 240A­h or (alternative Trojan J185P-AC  12V 20­5Ah if there is any benefit in a 2 batter­y setup against the 4 battery setup)?
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6 x 250Watt Mono Panels­
 ­
 ­
 ­
My questions are:­
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1. I have heard that flooded battery need­s to be topped up roughly once a month an­d then equalize? would my Axpert inverter­ be able to do this equalization or do I ­need to get another device to do this.
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2. The usage would mostly be for lighting­ (low energy bulbs + fan) so I intend to ­keep the DOD of the battery at a max of 5­0%, would there be a way to setup the Axp­ert inverter such that the inverter stops­ working once the battery DOD threshold h­as been exceeded?
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3. From my lay man's point of view, I bel­ieve a 4 battery setup is better that a 2­ battery setup for the same 24V, please a­dvise if this is the case or not.
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4. I also intend to feed the utility from­ the Power company into the inverter so t­hat the battery is harged whenever there ­is power supplied but nothing back to the­ grid, is there a setting available that ­requires very little maintainance except ­for the occassional battery top?
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 ­
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That would be all for now, I will post an­y further questions that come to mind, pl­ease feel free to make recommendations as­ approiprate.
 ­
Thanks in advance.­
 ­
dejavus­
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