more testing pics:

Whoa, the efficiency of the mppt inverters is incridble, just for discussion purposes, what is your take on micro inverters. They are on the rise here in North America and more and more hobbist are employing them against stand alone inverters, The debate on this top is very intresting as both sides are making claims for supremeacy, The truth is they both have good and bad sides. Micro inverters are more expensive than central inverters, while central inverters are less efficient if one of the panels gets blocked by shadow or has a issues from the manufacturer, the overall output of the system is reduced. Now you also have to look at the chances of that happening has well, if you go with microinverter, you can be sure to spend about $3000 more for a 10KW system than if you went with two 5000 watt central inverters. The micro inverter is the new technology, while central inverter is a well trusted and well developed technology with well know and documented draw backs. Micro Inverters also offer you the chance to buy what you need, for examples, if you go with stand alone, you have to buy a 5000w inverter for a 2300 W system, therefore you have 2800W of unused power untill you had more panels to your system, with micro inverters, you purchase one for each panel without having any excess unused power, but when you increase your system. you have to spend money on buying more inverters, while the standalone has the inverters waiting to be used.

In the aspect of Nigeria, Micro inverters will be the best option for someone with extremely limited capital as micro inverters allows the individual to only purchase what each panel requires, I am not sure if any one has used micro inverters on there system, but I sure would like to know who there system is responding,

percons,
thanks for the morningstar mppt charge controllers once again.

the mppt controller is certainly the way to go for solar charging.besides boosting current it allows to use higher voltage panels to charge lower voltage battery.imagine using a 34v to charge 12v!

as for the micoinverter i think its early days yet here in this part of the world but it will be interesting to see how it all plays out.

meanwhile testing is still in progress.

more pictures to follow soon.

percons,
thanks once again for the mppt charge controllers. i'm still finetuning and monitoring their performance to get the best juice from my panels.

micro-inverter technology is still early days for us in this part of the world and of course as you said, its not yet even tested on off-grid systems like mine. i think majority of solar enthusiats here will be careful to throw their trusted reliable central inverters away in place of an untested technology.

all the same lets keep our fingers crossed and see how it will eventually play out.

Hi George, what's the best battery system to power a 5kva load (24v) expected to run for 18 hours and what's the best way to charge it (solar and ac charger)
which battery would be best?

thanks and pls keep up the great work.

Nelson

mr nel, when it comes to solar system design, care is taken to get actual equipment power ratings in watts and not kva which is dependent on power factors.

hence going by your question,i presume you are talking about a system size of 5000w with a runtime of 18hrs?

if this is correct, you will need a minimum of 4 strings of 12volts 200ah batteries connected in series and parallel (i.e 2 batteries connected in series and 4 of such battery packs connected in parallel) making a total of 800ah.

for a 5kw system however its always advisable to use 48v or higher battery voltages and that will mean connecting 4 twelve volts batteries in series and using only 2 strings instead of 4. it helps to simplify your battery bank design while keeping voltage drop to a bare minimum.

for the best battery, personally i use zenith deep cycle batteries and they've been serving me well for the past 4 yrs. of course there are better batteries out there like trojan, interstate, etc but they are not readily available in these parts.

the best way to charge your battery bank is to use a combination of power sources. if you live in an area where there is fairly constant power supply, you may not bother with solar panels but if your living in a place where you hardly have public power, then you may consider investing in solar panels. in the long run it will pay you better than running your generator every day, every month, year in year out.

Much thanks George, We are talking of 8 to 12(3 strings) then, do you think I can maintain more than 50% discharge with this?

mr nel,
yes, you can maintain a battery dod of about 50% if you make it a 48v system and
add another string to it, i.e 1000ah battery bank.

much thanks George, however I don't quite get the 1000Ah part. A 4 by 3strings of a 12V 200Ah bank should yield 48V 600ah ? Not sure about that, forgive my asking but sometimes it can be confusing. Also by using 48V battery system one has to buy 48V devices? Thus a 700W dc airconditioner on 48v rather than 24 will require less Ampere and possibly more run time and lifespan for my battery?

mr nel,
power obtainable from your battery bank is the same irrespective of configuration.
i was only suggesting you need to add to your battery bank if you want to achieve
a dod of 50% as you want.

yes, a 4 by 3 string of 200ah (48v) will give you 600ah which also translates to
28800watt-hours.

the same number of batteries of different arrangement (say 24v) will give you 2 by 6
strings and you'll still get 28800watt-hours. the difference however is the amount of
current (amps) involved. the higher the system voltage, the lower your current and
hence the better for you. the reverse is the case for lower system voltages.

no, you don't need to buy 48v devices unless you plan on running your equipment solely
on dc current.

normally you will need an inverter which converts the battery dc voltage into alternating
current (ac) which is the type your regular generator provides, same with public power.
this gives you the flexibility to use any type of household appliance without having to
worry about input voltage.

him couldn't find your reply.

^^^ His reply has been flagged by the spambot. To read it, click on his username then click on "Show the last posts of this person."

mr nel, microgiant is right. my reply was flagged by the spambot and i was even temporarily barred from posting messages while the bot was busy reviewing my post. seems to me the spam bot is not happy with solar power as it keeps doing this to most of my posts on this thread 

anyways, i can see the spambot decided there was nothing really wrong with the post and has finally released it for viewing. it is back for you to read above.

pecorns:

Whoa, the efficiency of the mppt inverters is incridble, just for discussion purposes, what is your take on micro inverters. They are on the rise here in North America and more and more hobbist are employing them against stand alone inverters, The debate on this top is very intresting as both sides are making claims for supremeacy, The truth is they both have good and bad sides. Micro inverters are more expensive than central inverters, while central inverters are less efficient if one of the panels gets blocked by shadow or has a issues from the manufacturer, the overall output of the system is reduced. Now you also have to look at the chances of that happening has well, if you go with microinverter, you can be sure to spend about $3000 more for a 10KW system than if you went with two 5000 watt central inverters. The micro inverter is the new technology, while central inverter is a well trusted and well developed technology with well know and documented draw backs. Micro Inverters also offer you the chance to buy what you need, for examples, if you go with stand alone, you have to buy a 5000w inverter for a 2300 W system, therefore you have 2800W of unused power untill you had more panels to your system, with micro inverters, you purchase one for each panel without having any excess unused power, but when you increase your system. you have to spend money on buying more inverters, while the standalone has the inverters waiting to be used.

In the aspect of Nigeria, Micro inverters will be the best option for someone with extremely limited capital as micro inverters allows the individual to only purchase what each panel requires, I am not sure if any one has used micro inverters on there system, but I sure would like to know who there system is responding,

Micro inverters is suitable for grid tie system. It would be ludricuos to grid tie to nepa. The simple reason is, if you use microinverters with your panels, you eliminate the need for charge controller, battery bank and a central inverter. That means no power at night.

Kudos to you George_D you are doing a fantastic job.

akanniade,
thanks for that wonderful insight. i think micro-inverters are a bit early technology too.
who knows perhaps with advancement in solar technology, one of these days, they could
be modified for use with off-grid systems thereby effectively eliminating the need for solar
charge controllers.

161kwh on mppt and still counting! 

reaped a total of 6kwh from the sun yesterday!

wow, nice thread.
bookmarked!

even in the rainy season, you can never go wrong with solar.

mppt all the way!

details coming soon!

George_D,keep up d good work. I dont know much technical details about inverters, though i sell them but d good news is that d price of Solar panels is coming down while d bad news is dat d price of deep cycle batteries is going up.

chudieg,

of all solar energy products, deep cycle batteries are the only ones whose prices refuse to drop and
this a big worry to most of us on solar. lets pray that this trend will eventually be reversed.

George_D, do you know where I can get an 80amp dc breaker. I use an outback flexmax 80 charge controller. I am currently managing with a 63amp breaker.

akanniade,
i think you could get some from any of the solar stores in lagos. i too am looking for
a 100a dc fuse too.

now over 250kwh and still counting!

more pix!

some pix from my solar installation at home.

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Load testing with a 2.4KW electric kettle

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