the sukam now gratefully at rest, ready to spring into service at any slight opportunity!

overview of the new set up:

George_D,

Better moni kill sweet soup. Beautiful installation. We shall see by the weekend.

Waoooo its been a while since i followed this thread.
Sir George this is awesome....

Way to go bro Splendid job. Na Uduaghan suppose commission this your project o. . Congrats

George_D,

This is wonderful. Can you just give an idea of the Cost of 2Kw setup

Woh!!! Speechless!! Welldone

rodgers: George_D,

This is wonderful. Can you just give an idea of the Cost of 2Kw setup

The cost will almost return you to your village if you had one...LOL, in this business of renewable energy, you are better counting what you stand to gain, not what you need to spend.

BUTONEDAY: George_D,

Better moni kill sweet soup. Beautiful installation. We shall see by the weekend.

bros butoneday,
no be small thing o! i just felt i needed to improve on what i got already to maximize performance.

freshp, akanniade,

thanks guys for the compliments. i appreciate.

rodgers,
although bodejohn is exactly right, you should not let the cost discourage you. while it is always good to
have a clear idea of cost implications, the emphasis should not be on cost alone.

now to your question, depending on the set up of your system, a 2kw system could be anything from 300k to 600k.

you need:

1) a minimum 48v battery bank (4pcs 12v 200ah batteries)
2) a 2kw inverter
3) a change over switch
4) a minimum 4pcs 200w solar panels.
5) half a roll or a full roll of 10mm multi-core copper wires (black and red)

however, i'll advice that you forget about adding solar panels for now and just go for the battery and inverter.
that brings your cost down to a little below 300k. with time you can always add solar panels as you go along.

Oga George, i forgot to congratulate you on the successful upgrade.
I also have some questions for your setup.

I can see a prag stabilizer in the picture, it is the relay or servo type? which power source are you trying to stabilize?

Your 3.5kVA sukam inverter operates on 24V or 48V? Will it at any point in the near future be up for sale?

Did you directly couple the outputs from the mppt controllers into the batteries? I am asking because i can see that the charge available from the mppt controllers are not equal.

Are you using any special connectors like the MC4 for the cables from the solar panels?

Was there any special recommendation for the fuses between the mppt controller and the solar panels? Why not a circuit breaker instead of the fuse?

I am a newbie from Kenya though i have been following the thread. I have a set up of 2 x120W solar panels, STECA PR3030 charger controller, two 12V 100Ah champion batteries, OPTI-UPS IS1100LT 1100VA/660W (24V)inverter. The batteries are connected in series, the problem is the state of charge does not pass beyond 65% even when the sun is hot from morning to evening and it drops significantly when you switch on the appliances. The total load of the house is 650W though i use 75W tv for 2 1/2hrs, 20W for 1hr, 14W for 1hr, 36W for 1hr but the system cannot run more than 3hrs and the load does not run simultenously. I also have 135W tv and cann't use it coz at times on switching on it switches off the inverter and the system running is reduced. What could be the problem and remedy to these?

permie: I am a newbie from Kenya though i have been following the thread. I have a set up of 2 x120W solar panels, STECA PR3030 charger controller, two 12V 100Ah champion batteries, OPTI-UPS IS1100LT 1100VA/660W (24V)inverter. The batteries are connected in series, the problem is the state of charge does not pass beyond 65% even when the sun is hot from morning to evening and it drops significantly when you switch on the appliances. The total load of the house is 650W though i use 75W tv for 2 1/2hrs, 20W for 1hr, 14W for 1hr, 36W for 1hr but the system cannot run more than 3hrs and the load does not run simultenously. I also have 135W tv and cann't use it coz at times on switching on it switches off the inverter and the system running is reduced. What could be the problem and remedy to these?

@ Permie, it seems although not completely clear that you are off grid, that is, you only charge your batteries with the solar panels.
If this is the case, the timing that is bolded above does not add up for me.

I am attaching a simple excel sheet that will give you an idea of what you require in terms of battery bank and solar cells.

Cheers!

hello bodejohn,
let me try and answer your questions as concise as possible:

1) the 10kva prag stabilizer in the picture is the servo type. i'm stabilizing the phcn input power supply
from the mains into the cyberpower inverter for charging the batteries and re-supply to the house (when needed).

2) it is very unlikely that i'll be selling my sukam inverter anytime soon. presently i'm still test running the
cyberpower and i've realised that the 3.5kva sukam is able to carry all the loads that the 5kva cyberpower is
carrying. hence, on the contrary i'm thinking there is a chance i might be tempted to put up the cyberpower for
sale after the testing period is over. most likely.
the sukam operates on 48v same as the cyberpower inverter.

3) yes, i fed the outputs from both mppt charge controllers directly to the voltage combiner (which is a kind of
distribution board for the batteries charging input as you can see from the pictures). irrespective of individual
charging current, the charge controllers output separately into the battery bank, working in series to increase
overall charging current - provided output voltage for both controllers are the same at 48v each, so no conflict
at all.

4) the earlier panels i installed only had mc3 connectors on them but the latest suntech panels in the picture came
with mc4 connectors but other than direct string connections, i'm not using them as of now. in subsequent upgrades,
i plan to purchase various lengths of mc4 and mc3 extensions so as to make for a more professional installation.

5) yes, technically you should always rate your fuses to be at least 125% of the current carrying capacity of your
cable. i didn't really follow that to the letter in this installation.
i opted for cut-out fuses instead of circuit breakers because i couldn't lay my hands on dc circuit breakers which
is the type recommended for such an installation. all the circuit breakers you find around in these parts are for
alternating current (ac) which is dangerous to use on high voltage/high current dc installations as these.

warning: never use a normal ac circuit breaker on a dc circuit. the high dc voltages and current involved will
cause arcing at the tips of the cb which may cause a fire!

there are special dc circuit breakers recommended for safe installation of dc circuits. a popular brand is made
by midnight solar and this will form part of my future upgrades in the very near future, the good lord willing.

permie,
1) your solar panels are way too undersized for your system and they're not able to bring up your
batteries to full charge.

2) your load usage is rather heavy for that size of battery bank hence you end up over-discharging the
batteries way beyond their safe dod.


solution,

use the system sizing sheet bodejohn attached in his post and do a proper sizing for all your loads.
you may have to consider increasing your battery bank size and also your solar panels. on the
alternative think of the possibility of augmenting with public power for charging the batteries when
available.

bodejohn:

@ Permie, it seems although not completely clear that you are off grid, that is, you only charge your batteries with the solar panels.
If this is the case, the timing that is bolded above does not add up for me.

I am attaching a simple excel sheet that will give you an idea of what you require in terms of battery bank and solar cells.

Cheers!

Thanx alot Bodejohn, its on an off-grid area. I'll work out on the excel sheet and report back the finding

George_D: permie,
1) your solar panels are way too undersized for your system and they're not able to bring up your
batteries to full charge.

2) your load usage is rather heavy for that size of battery bank hence you end up over-discharging the
batteries way beyond their safe dod.


solution,

use the system sizing sheet bodejohn attached in his post and do a proper sizing for all your loads.
you may have to consider increasing your battery bank size and also your solar panels. on the
alternative think of the possibility of augmenting with public power for charging the batteries when
avauilable.

Thanx George D, its an off grid area for my grandpa though it will be on grid soon and aid in charging the batt's. I'll use the sizing sheet since at the moment am using a phone

@ George.
I thought I was following well as a good student, but i got somehow confused again. I've tried going back to the posts were you may have answered similar question but still unsure;
1. Theoretically, the output from solar goes into the MPPT charger whose output connects to the battery terminals. Why do you have a fuse (or breaker) between the solar & MPPT charger.

2. It also seems you have a fuse between the MPPT charger and the batteries. is that right? If yes why so?

3. What exactly is the MC4? What do I loose not having it?

4. The fuse you used are similar ones we use for AC (NEPA cut out) right?

5. You posted that one needs a minimum of 4 solar panels. My plan is to get 2x 250W x 24v for a start. Wouldnt that work (in conjuction with the NEPA & GEN sources)?

Apologies is my questions are silly

hello pdozie,
your questions are very much in order. remember that there are no stupid questions only dumb answers!

1) yes, you are very correct. the output from the solar panels goes into the mppt charge controllers which
outputs into the battery bank. you need a means of interrupting current flowing from the panels to the charge
controller for those occasions where you want to carry out maintenance works on either the solar panels,
charge controllers or battery bank. for instance it would be very unsafe working on your solar panels without
isolating them first. same goes for your battery bank or charge controller. imagine trying to tie in additional
solar panels to a live system in the full glare of the sun at midday! also you are changing out your inverter
but the modules keep feeding in current to the battery bank through the charge controller. or you are
configuring your charge controller while it is still live on voltage. how wise is that?

2) yes, there is a cut-out fuse between the batteries and charge controller for the very same reason already
explained above.

3) the mc4 connection is a type of connection for solar panels and is an improvement over the mc3 which is an
older design.

for more on this you can check out this link: http://en.wikipedia.org/wiki/MC4_connector

4) yes, the cut-out fuses i used are similar to the type used for phcn connections. as far as cut-out fuses
are concerned, there is no difference between ac and dc current. where the problem of arcing comes up is with
circuit breakers and with that you need to be careful to avoid using normal ac circuit breakers on dc
installations to avoid risk of smoldering/fire.

5) my suggestion of a minimum of 4 solar panels is just a rough estimate of what you'll need to get going. it
could be more and it could be less. sometimes, depending on availability of public power in your area you may
not even need any solar panels at all. i ran my inverter solely on public power for over two years before i
began adding solar panels.

all,
testing pics from the new kid on the block:

congratulation George D. truly i am impressed and challenging. you must hv reduce seriously your % dependence on NEPA. well we are gearing up too in the north here to follow suit. this is encouraging.

@George,
Many thanks for the clarifications. Well understood

Hi George D,
great setup, well done. quick question. pls what is d highest safe voltage 4 {2}100ah battries in paralelle can charged upto because @ 13.4v my pwm controller starts pausing indicating that the battries are full.

idsolar: congratulation George D. truly i am impressed and challenging. you must hv reduce seriously your % dependence on NEPA. well we are gearing up too in the north here to follow suit. this is encouraging.

idsolar,
its been quite a while. yes, your observation is correct. with my present set up, i now routinely switch off
from public power especially during the day so as to enable me optimize solar harvest from my modules.

i pray the rest of us will be able to get up to this level in due course. amen.

pdozie: @George,
Many thanks for the clarifications. Well understood

you're welcome.

obijack: Hi George D,
great setup, well done. quick question. pls what is d highest safe voltage 4 {2}100ah battries in paralelle can charged upto because @ 13.4v my pwm controller starts pausing indicating that the battries are full.

obijack,
the highest safe voltage for a 12v battery should not exceed 13.4v so your pwm controller is correct when it
indicates your batteries are full at this voltage.

ok, normally a 12 Volt battery is fully charged with an at rest voltage of around 12.7 (+/- depending on manufacturer's specs).
to get there, deep cycle batteries need to be taken up to 14.2 to 14.8 (again depending on the particular battery) absorb voltage and held there to complete the charge.
then there's the float voltage which is a level that is maintained as long as possible to keep the system working well. this is usually around 13.8 volts and can be as low as the resting voltage. again it depends on the battery maker's numbers.

however, it all depends on the particular battery, how accurate your pwm charge controller is and of course your ambient temperature.

This is wonderful Goerge, well done! I hope you're neighbours dont plan on building storey buidlings though, LoL....

Seriously, at what NEPA is charging for electricity nowadays, it makes sense to start with solar... I use about 25 units a day!!!

fikfik,
thanks. fortunately i live in a neighbourhood comprising mainly of bungalows. the nearest storey
buildings are a bit far away.

as for phcn charges, i think you're right. as tarrifs go up, alternatives like solar suddenly begin
to make more sense. and, we haven't even gotten to the privatised electricity rates yet.

Oga George, more questions for you again.

How does charging you battery bank with 2 solar chargers compare with charging via the inverter when there is grid power on a sunny day?

I read in a piece that only the source with the higher power level gets to the battery while the lower is blocked.

Secondly, I noticed that your panels are arranged at the very top of the roof, any reasons for this? How often do you clean the panels?

hello bodejohn,
you can charge your battery bank simultaneously with multiple charging sources including solar, wind, hydro,
public power, etc. that is what makes it a hybrid system. the most important consideration however is the system
voltage (your battery bank voltage). as long as all these charging inputs maintain the same voltage range as that
of the battery bank, there will be no conflicts at all. if you have more than one functional charging source, the
only thing you'll notice is that your batteries get full quicker and they always remain in a fully charged state.
now as for one source overriding the others, that doesn't happen as we are not talking voltage here but current.

for instance you have two solar charge controllers feeding current into a 48v battery bank. one is outputting 15a
and the other is puting out 25a; total solar charging current feeding into the bank will now be 35a at 48v. if there
is public power at the time and the inverter is also charging the batteries, let's say the inverter's charging
capacity is about 25a, combined charging current (solar + inverter) will now be 60a all at 48v battery voltage.
they continue to do this as battery voltage rises quickly with more current flowing in. after a while, depending on
the charging configuration of the solar charger and inverter, when the battery becomes full, either one of the charging
sources begins to knock off one after the other and go into float mode. what normally should have taken 6 to 8hrs for
a full charge now takes just 3hrs or less depending on the performance of the sources. in a hybrid system, no one
charging source will override the other contrary to your suggestion.

how does solar charging compare with charging via phcn? of course the better alternative is to always use grid power
(when available). however for those occasions when grid power is not available, solar comes in as the next best
option. grid power is not affected by weather, clouds, etc. for solar there are days when the sun only shines for
two or three hours max and you have to put up with rain or clouds for the rest of the day. again, with proper
system sizing you can always overcome this.

my panels are arranged on the roof because that is about the highest point on the building where they can have
unhindered access to sunlight. i don't clean them (although i would have loved to be able to do that). i rely on
the rains to do that for me. so far that method has been working fine.

Oga George D,How much did get those solar panels.then how many do i need for 3kVA OR 5kva sine wave solar inverter. waiting for response asap sir.Thanks