Upgraded

It's Earth Hour again tonight, and I think a solar posting is therefore appropriate.

RSon convinced RMan to reconfigure the solar panels - to allow for
additional panels to be added in future - IF they were required.

In June 2014 we removed, re-wired / adjusted and re-installed / re-configured our 8 X 145 watt solar panels in parallel (amps) instead of the original series (volts) and the voltage spiking we had been experiencing during the coldest time of the morning (sunrise) was solved.  The 80 Amp Outback charge controller remained, but we also upgraded our Cotek inverter from 1000 watts to 2000 watts.

The system has served us well and has kept the house running for just under 5 years.

But, our initial mistake in 2012, was to install a 12 volt system.  Our (uneducated and, in hindsight, illogical) reasoning at the time was that camping stuff is mainly 12 volt (to run off car batteries) and therefore those off grid appliances available to us would be in 12 volt.  Plus - honestly - it was what we could afford at the time.

However, appliances that are now being manufactured are far more solar power friendly - using less watts to perform the same duty, if not more, as the limited older make appliances.

But our major power guzzler is our fridge.

We purchased an A+ fridge / freezer combo in December 2014 which only uses 132 watts / day (or 484 kWh / year).  But - a fridge works 24 hours a day - during the daylight hours it draws it's power from the batteries which are concurrently being charged by the panels, and it continues draining the batteries during the night - when no charge is happening.  In itself, that would work brilliantly, but add to that all the other household gadgets (TV, decoder, wi-fi, phones, laptop and printer [9 hours a day for our business], once a week vacuum cleaner (the broom suffices on the other days), lights, bread maker every other day, etc and our batteries were taking a bit of strain.

One of our 6 X 2 volt lead acid batteries failed over December - when the solar suppliers were shutdown for the Christmas season.  Isn't that always the case!?!  One of our neighbours, who had just experienced a break-in, and theft of his 3 X 240 watt panels, charge controller, inverter and 1 of his 5 X lead crystal batteries, kindly lent us his remaining 4 batteries which the thieves had found were too heavy to make a quick getaway with.  That act of kindness also ensured that his remaining batteries were not left in situ / vulnerable for the thieves to return and collect the balance of his system.

RMan was very impressed with the performance of the lead crystal batteries.  They have the ability of being able to be "drained" pretty low without retaining a memory of that drain - as is the case with the majority of other solar batteries.

So, RMan decided that an upgrade of our system would be in order.

We ordered another 2 volt lead acid battery to enable us to continue with our original 6 X 2 volt (12 volt) system.

In addition, we ordered 3 X 300 watt solar panels, 4 X 12 volt 200 Ah lead crystal batteries and a 5 kva 48 volt Replus charge controller and pure sine inverter combined.  The beauty of the Replus is that it is one unit, instead of two, and, providing enough power is being produced by the new panels, it enables power to be drawn straight from the panels whilst the panels are simultaneously charging the batteries.

The new 4 X 200Ah 12 volt lead crystal batteries are wired in series to provide 48 volts and do not produce any fumes - unlike the old 6 X 2 volt lead acid batteries.

With the roof space that the reconfiguration provided, there
was more than enough space to add 3 X 300 watt panels

Naturally, RSon to the rescue once again - climbing round the roof to install the new panels...  even though the 300 watt panels were much heavier than the 145 watt ones, at least he had the lower roof to stand on, which made getting them up on the roof and installing them much easier.

We have the two systems wired separately.  And - after RMan did a fiddle here and there, and installed a new power source to the house - they supply power to two different parts of the house. 

The old system :
6 X 2 volt lead acid batteries
 Outback charge controller and
2000 watt Cotek inverter

The old system powers the bedrooms / lounge / garage (minimal drain from there - just power tools every now and then).

The new system powers only the kitchen i.e. fridge plus 2 plugs (1 for my "Audi lights" and the other for my blender stick / mixer and bread making machine).

With 3 X 300 watt panels, wired in parallel, feeding 4 X 200Ah lead crystal batteries, power generation / provision to the kitchen is brilliant and, most importantly, less demanding on the system.

4 X 200 Ah lead crystal batteries
 and the Replus charge controller
 and inverter combined.

S'funny - you would think that a couple of low wattage lights, a TV, decoder and wi-fi (+/- 40, 35 and 30 watts respectively or +/- 120 watts together) would be easy for a system to handle.  But, over the course of an evening (4 - 5 or more hours) that equates to 600 + watts.  Add that to the fridge which runs for 12 minutes every 8 (on for 12 minutes off for 8 minutes ) and power consumption at night was generally working out to be higher than the entire house during the daylight hours.  We were consuming +/- 2 - 2.5kWh at night - when no power was coming into the batteries and the 6 X 2 volt batteries (when it was overcast for extended periods) were sometimes battling to handle it on their own.

Now that the load is shared - I am even able to use my 1200 watt hair dryer for 8 - 10 minutes (once a week) - providing that I use it during daylight hours - and have allowed the batteries to have a bit of charge before I place such a high demand on them.  So, until about 9.30 - 10.00 a.m. my hair drips dry.  Thereafter I am able to give it some semblance of a style.

Definitely no more power worries in this house anymore.

Cost?

For a stronger, more powerful system it was approx. 50 -55% of the total cost of our original solar set-up.

Sometimes I get giddy at the amount of power I now have at my fingertips... :D

Our old system, which is 5 years old, has paid for itself.  5 years of powering our home / business "head office" - if we has used grid power we would have paid more than the original system cost us - for the rural levy only (+/- R680.00 / month)!!!  The cost of the KWh we used would've been added to that.  Our old system is still going.  And now it's life is extended because it has "help" :D

We will not have to switch off our lights for Earth Hour tonight because we, personally, don't need to protest against our power being supplied by coal fired nor nuclear powered power stations - notwithstanding the power required to produce the various components - for only the sun is providing the power for us to use.

However, for the sake of this planet - long term - and for the sake of romance, we will be using only candle light tonight... :D

Disclaimer:  Products mentioned on this blog posting are products we have purchased for our purpose.  That does not imply they will be sufficient for your requirements / purpose.  No supplier is aware, nor has paid us, for mentioning their products.

For info on how you can obtain your own Foothills DryAway solar / wind food dehydrator please click the link.

Reality of solar power costs

I get many e-mails, especially from others in South Africa, regarding our move off-grid.

So many people in South Africa are totally fed-up with Escom's load shedding shenanigans (enforced blackouts) and are eager to go off grid, but I think that the unknown cost of that is inhibiting most people from making the change. Perhaps it would be easier if I broke down the cost of our 1.12kWh solar system.

First, though, when we left our town house and moved to our smallholding, we were using approximately 15kWh / day.  At the time that was costing us ZAR1.37 / kWh.  Therefore 15kWh / day was costing us ZAR616.50 / month.

Minimum grid power costs over 5 years if we
had stayed in our town house

As you can see from the above, if we had not moved to our smallholding and gone off grid we would have spent approximately ZAR54 271.20 (excluding V.A.T.) over a period of 5 years.  And that is calculated at an annual increase of only 8% / year.

The minimum grid power costs over 4 years
on our smallholding 
- if we had availed ourselves of the service

Plus, if we had continued using Escom on our smallholding we would have had an additional service fee at a cost of ZAR589.00 - ZAR715.93 per month.  But, our electricity bill would have been even more than the total monthly amount in the image above.  Our smallholding neighbours spend on average ZAR 1200.00 - ZAR1500.00 / month.  Why - because they are not aware.

So - now to the costs of our solar power system.

As you can see from the above our system cost us ZAR54 886.39  That was back in 2012 - the cost of solar panels is lower now than it was then, so that cost would be reduced even further.

To me there is no comparison.

We live quite normally.  You just earn to become more aware.

If you discover that you require the use of a fridge and a freezer, and you don't have the power output for 24 hour use of both, then, if you are able to purchase a better energy rated side-by-side fridge /freezer unit, as opposed to plugging in a separate fridge and a freezer, you can have that requirement fulfilled.

Similarly the washing machine.  Front loaders use far more energy than a top loaders, and a cold water wash will clean 99% of your clothing as well as a hot water wash will do.

Selling on your now redundant appliances helps to offset the cost of the new ones.

Our Owl electricity monitor

We  have become completely aware of exactly what appliance / gadget we switch on, and for how long.   Providing you keep your eye on how much power your panels have produced (via the charge controller), and, with the assistance of the Owl electricity monitor (or similar), how much power you have consumed, then you can judge what you can switch on at any time on any given day.  This is especially true on wet, rainy days when less power is being produced.  Funnily enough, dry overcast, or cold sunny days often produce more power than full sun, hot days, This is because the heat generated by the sun on the solar panels reduces their efficiency.

For us, the current scenario is that in comparison to what grid power would cost us, within a maximum of 3 - 4 years our solar system is producing electricity for us at no charge - with absolutely no electricity price increases amortised into the cost of it's set up :).  The panels have a 10 year lifespan, and the batteries a 20 - 25 year lifespan.

Now, if only Escom would, firstly, agree to more sustainable power production via solar panel and wind turbine farms, and, secondly, allow for those who produce their own power to feed their excess back into the grid, then perhaps they wouldn't be in the mis-managed, shortsighted position in which they are now finding themselves - a position from which the whole country, and it's GDP / current and potential international investments, are suffering...

There you have it.  The nuts and bolts costs, and pro's and cons, of installing and living with solar power.

Powered up...

Warning - this is a l-o-n-g posting, and picture heavy...

A few days ago I mentioned that we had some very exciting happenings at the farm.

Well, here is the news...

We have learnt a lot about our solar power installation through trial and error. When we initially installed our solar panels we were not informed about a number of things which were vitally important.  In this instance, we were not informed that low temperatures affect the performance of solar panels.

When the ambient temperature is below 10oC the cold affects the voltage of the panels - causing the voltage to spike.  We had all our 12volt panels (incorrectly) connected in series - all the way through to our charge controller. Connecting them in series meant that maximum volts were produced by the panels - which is what RMan was (mistakenly) aiming for.  (connecting the bank in parallel would mean the Outback charge controller would utilize the Amps produced, not voltage.)

We have an Outback 80 charge controller, which, translated that means it can handle an input of 80Amps and 145 volts power from the solar panels - maximum.

Our indoor Outback remote display gives us the
first /indication that all is not well with our
power production.
Silent - at 9.40a.m. in the morning -
is not good news.  It means the voltage
from the panels is spiking

What we discovered last year (winter) is that at sunrise, when the temperature is the lowest, the cold caused the panels to spike over 145 volts - the maximum the Outback charge controller could handle - which caused the charge controller to shut down.  For hours.  Which resulted in lost input charge to the batteries.

Checking in the power room, the Outback
charge controller tells the tale : 148VDC
High VoC = shutdown - to prevent damage
to the charge controller

Given the number of people world-wide who are off-grid and who rely on solar power to charge their storage batteries, I did not believe that the problem was unsolvable, so after contacting a number of people locally - who didn't help much - I went international.  An extremely helpful gentleman at Outback technical support in Australia, responded to my high voltage e-mail query. And, over the course of 16-odd e-mails [I told you you he was extremely helpful :) ], he advised us to reconfigure the panels.

Diagram of the new configuration of our 8 X
off-grid solar panels connected in series and
the two banks connected in parallel.

He suggested that we have two equal banks of panels linked in series, and then link the two banks in parallel with two breakers separating the two different guage cables between the panels and the charge controller.

Wiring into breakers
prior to being routed
through conduit

Breaker details

To do that we needed an equal number of panels.  We only had 7 (6 X 140watt and 1 X 135 watt).  Wayne, our SiL across the field, had two 140watt panels that he wasn't using, so we purchased them off him - thereby removing of the 135 watt panel from the exisiting array.  These 8 panels give us 1120 watts of potential solar power going to the Outback 80.

6 guys in the front and two guys behind -
installing our first 5 X solar panels in August 2012.

Plus, RSon had the very good suggestion of re-installing the solar panels in such a way that we would have available roof space if ever we wanted to install more panels in the future (our old existing installation "hogged" all the available space of over half the roof area).

But, that meant getting all the panels down off the 45° pitched roof.

You recall how the builders assisted us in installing the original five panels on the garage roof.  7 guys helped RMan that day.  Five in the front with RMan...

 ...and two holding support ropes at the back.

This time we only had RMan, RSon, Wayne and one of the locals we roped in to help.

I was fraught with fear.  Those panels are frigging heavy.  And the pitch of the roof is hectic - and not condusive to ease of clambering all over it.

The scaffolding was errected, and the removal proceeded at 11.00 a.m. on Saturday morning.  I was torn between not wanting to watch / document the event, but being aware that the more I photographed, the more info we would have if we ever needed to check something in the future.

RMan and RSon discussing the best way to handle
this enormous task - and RSon giving us an
idea for the addition of further panels in future

RSon, ever the adverturous one, elected himself to climb to the roof apex in order to connect the supporting ropes to the exising array.  And to loosen the existing bolts securing the solar panels to the roof...

RSon, Wayne and the helper trying to get the
panels off the roof

A couple of times I remember pointing the camera, closing my eyes and clicking the button.   I couldn't watch...

Since the first time we installed the panels, we have erected a carport roof - and that carport roof was in the way when it came time to secure the supporting ropes.

The carport roof was in the way, so we had to
secure the supporting ropes to a quaddie

 It was very hot and difficult work - with awkward access all round.

Removing the old cables so that we could get the
panels down

But, my fears aside, naturally they got the panels down in one piece, and without injuring anyone.  There is a God in heaven.

Checking and rwiring the panels and re-fixing them
to the horizontal aluminium square tube supports

We had purchased more cable with which to rewire the panels - and that was just as well. We discovered that one of the old cables had become pinched during the original installtion - and that was not good news!

As we are going to be installing the panels in a different configuration, the supporting beams inside the garage roof had to be moved as well.

The horizontal beams fixed to the trusseses
support the solar panels

(Ah - a small bit of news I forgot to give you - RMan managed to break his new-ish glasses a few weeks ago, and, although new ones are already on order, all close up work has to be done with his prescription sunglasses.

Inside a garage roof??!?!)

Wayne to the rescue again LOL

Oh, brother!!!!  The roof mounted bolts were
installed in the incorrect position

Once everything was rewired and refixed to the aluminium supporting structure, the first bank of 4 panels was once again hoisted up the scaffolding and onto the roof.

RSon at 5.59p.m. - perching like a monkey
 on the rooftiles in the fading light.
I definitely gained a few grey hairs watching him...
Does he know how long 9 months carrying a
child is, and what is involved in getting that child
to adulthood?????

All of this takes time.

They started at 10.30-ish in the morning and, at 5.59p.m. the first bank was more or less installed.  They had installed the securing bolts from inside the roof outwards.  Then trying to find the holes on the aluminium structure below the panels wasn't easy in the fading light - and it took ages.

So, Sunday morning the work continued...

Getting the securing bolt lined up with the hole
in the roof tile

The securing bolts for the second bank were installed from the outside in i.e. first through the aluminium square tube and then into holes drilled through the roof tiles.  Far easier.  Even given the raging gale that inconveniently sprang up to hamper the operation.

The new two banks of 4 X panels - using less roof
space than the previous installation - and producing
200 watts even in the cloudy weather evident on
the photograph.  This installation allows for a
further 8 panels to be installed in the future.

So, finally we have two banks of 4 X 140watt panels (which are connected in parallel this time) mounted on the roof again.

And - thanks to RSon's foresight, we have space to install a further 8 - 12 panels should we so choose in the future :)

Clever boy :)

The battery / inverter connections remain the same

So - there you have it.

The next day it was immediately apparent that there is a definite, and visible, improvement - 10 minutes after sunrise we are already getting a charge going to the charge controller and 30 minutes later over 300 watts is being produced.  With nada voltage spiking / shutdown occuring.  At the end of the day, we are obtaining 5KwH+ of charge to the batteries - in winter!!!! :) That we only achieved last summer.

And - there is no more over voltage spiking :D  So every scrap of power produced by those panels from the moment the sun hits them in the early morning to the last ray in the evening is now going to the charge controller and into the batteries.  Yipeeeeeeee!

Well done guys.  And, thanks - seriously - a very sincere and grateful thank you for all the work, willingness, thought and effort that you all expended to sort out our power problems.


By the way, tomorrow we will have been here for exactly 2 years :)  How fast the time has passed and how worth the move it was.  No regrets - neither RMan nor myself :)


P.S.  You have only 2 days left if you'd like to add your name to the piquanté pepper seed giveaway.  Entries close at 6.00p.m. on Monday, 30th June 2014 :)

Sunny days

We had our best day ever for solar power on the 22nd February 2014.

The days' temperature was in the early 30°C's but there was a nice breeze wafting across the solar panels.  That made it ideal for power production.

5.3kWH / 399 AH went into the solar batteries

The Outback Charge Controller remote display informed us that we had received 5.3kWH of power into the batteries...

Only 3.42kWH was consumed by our appliances /
gadgets

...but we had only used 3.43kWH at 17.58p.m.

That gave us an additional 1.9kWH.  More then enough to watch our 60 watt TV until 10.00p.m., power our 180 watt fridge (on it's timer - one hour on, one hour off) through the night, and still have the batteries well charged the next morning :)

Nobody - but nobody - tells you when you purchase a solar system that:

1  The hottest days are not the best for charging solar batteries.  If the solar panels get too hot, they don't produce, nor provide, optimum charge to the batteries because overheating reduces their efficiency.

2  The cold winter mornings are also dicey.  If the solar panels are too cold due to the ambient temperature, even if the sun is shining on them, they don't absorb the energy to charge the batteries until they warm up.  Which could mean 9.30 - 10.00a.m. before they even start supplying charge to the batteries.

Be warned.

But, even with that said, I would not change back to grid power!  I'm loving our solar power.  Honestly though, it does take some getting used to what can be run on our total 980watt solar panel system, but once you get your head around that, it's a breeze :)  And, if we ever find that we need dramatically more power (mainly for power tools) then running the genny for a hour or so takes care of that!

No Escom blackouts in this household LOL

Ramblings on our solar power

Firstly, welcome to my newest followers, Amy Lou from northern New Mexico. Amy Lou is a fellow off-gridder :)

On her blog Solar Rain Bucket, Amy Lou describes herself, and her blog, as follows:

 "We live off-grid in Northern New Mexico. Solar power. Rain catchment. Composting toilets. All that. Solarrainbucket is where we share what we’ve learned. And post pictures of dogs. And sometimes clouds."

Welcome, Amy Lou - thanks for hitting the followers button.

-------------------------------------

Having just lived through our very first winter relying solely on our solar power setup, I thought I'd do a posting on the in's and out's of it.

We had a gradual slink into the winter weather - we got comfortable and thought "Ha! this is a breeze".  Then the overcast, and sometimes rainy days started.  Two or three days of overcast weather plays havoc with the state of the battery charge.

Our original 3 x 140watt
solar panels, secured to
a contraption on the front
patio whilst the building
work was in progress

2 of our original deep cycle
batteries.

Our system started 3-odd years ago, when we could least afford it.  So we opted then to go for 12 volt - panels, charge controller and inverter.  B-I-G mistake. In hindsight (it's always easier, isn't it :) ).

Our 6 X 1660Ah 2 volt battery bank

The most important part of living off grid - be that achieved through using only solar power, or that produced from a wind turbine, or both, is your storage capacity - your batteries.

Our first lot were 12 volt deep cycle batteries.  When we moved here, we changed them out for 6 X 2 volt batteries.  SIX!!!!???!?!?  Idiots, even though they were the major expense in our system, we should have gone for 12, strung the two sets of 6 in parallel (to increase their capacity but not their voltage) so that they retained their 12 volt capabilities, but were also usable in a (future) 24 volt system.  And, it's not as though we can buy another 6 now and add them. That would be a complete waste of time, as the newer ones would be affected by the older, more used ones - to the detriment of the new ones.  Also, buying 12 news ones is out of our budget at the moment...

Also, we should've purchased a charge controller and inverter which allowed for either 12 or 24 volt. They are available, but are, naturally, more expensive.  Sigh - it's all about affordability.  But, with that said, don't do what we did, rather scrimp on other things, and buy for the future of your power requirements, not just for the moment.

Seven 140watt solar panels mounted on the
roof of our garage.  Excellent north facing
45° angle to the roof, but the accessibility is
horrendous...

Our 7 X 140 watt panels are connected in series (i.e. + to - in order to increase the volts) and mounted at the 'ideal' 45° angle facing north (in the southern hemisphere), but, being mounted on our garage roof, they are also awkwardly inaccessible.  We figured 7 X 12 volt = 84 volts = well within our charge controllers capabilities.  But, we didn't know that solar panels are as cold as their surrounding temperature in winter, and due to this cold, you can have a situation where their voltage spikes in the early morning ( 8 - 9 a.m.) - which causes, in our case, their combined output to hit over 145 volts - and our maximum is 150. This causes the charge controller to shut down because it is receiving too high a voltage.  Shutting down means we are not charging our batteries when they need it most - after a long, dark night LOL  We have found that if we physically trip the fuse from the panels to the charge controller and allow the charge controller to "reboot" then the power surges into the batteries with little or no problem.  This action is not ideal though.  If we left the charge controller to "fix" itself, it will, but, in the meantime we are losing precious charge from entering the batteries during those long winter days of dramatically reduced solar input.

Our Outback charge controller

What we have also determined (through speaking to a very helpful gentleman called Lloyd from a ADSolar in KwaZulu Natal ) is that we can wire half (4) of the panels in series, and the other 4 panels in parallel - that way we will get the best of both - volts and amps. This, hopefully, will prevent the voltage from spiking next winter.

In summer, this will not be a problem.

Installing the 5 panels was a mission when we had
7 helpers (two are taking the slack off the rope
behind the garage). RMan, RSon and Wayne -
that's going to be interesting...

So, RMan and RSon and Wayne - guess what you will need to do this summer? Take the existing 7 X 140 watt panels down, add the soon-to-be-purchased 8th panel, and then rewire the 8 panels in series and parallel respectively, and re-install them...

Not a task they, (nor I - it's fraught work watching our solar panels being manhandled off and on the roof), am looking forward to... :)

On the positive side, we didn't run out of power this past winter, but some days it has been decidedly dicey.  And, to reduce the demand, we had to be very careful about what we switch on, and when.

The 600watt battery charger -
even though we only used it a few times, it
certainly was worth it's cost

We also purchased a 600watt battery charger, which is operated through switching on our petrol generator.  A very occasional (as in 6-7 times during the entire winter period) hour or two of charge happily gets us (the fridge) through the night... :)

So, although we discovered the con's of our system, we managed.  It was, through the monitoring of our remote control SoC apparatus in the house, careful use / prioritizing appliance use, and the assistance of the battery charger, all do-able.

Life was very comfortable, with all the important appliances fuctioning when required and the Rosie creating a wonderful, warm and cosy home - even with snow on the mountains...

For "Just Me"

I received the following welcome e-mail from Just Me 

Dani - thank you so much for sharing all of the details of your PV system in these two posts! If I'm not being too greedy, can I ask for one more photo of the display on your Outback charge controller - when the IN voltage is under 60 and the OUT voltage is still over 12. I know there are a lot of folks watching and learning from you. The MPPT controllers are generally much more efficient than the less expensive PWM charge controllers, but the differences lose a lot of folks in the math. That difference becomes really obvious when you look at panels connected in series for an MPPT controller versus panels connected in parallel for a PWM controller. When the panels are putting out less voltage than the battery level, a PWM controller will not charge the batteries at all but an MPPT controller will continue to put watts in the bank until the sum of the panel voltages drops below the battery level. This makes a HUGE difference on partly cloudy days and early morning and late evening. With your setup, you should still be drawing solar power into the batteries when each panel's individual output has dropped to 3V! Well done! 

Well, Just Me, here is the pic as requested...

This pic of our Outback charge
controller was taken at 7.00p.m. when
it was overcast and dark outside

Here is a close-up of the Outback charge controller screen:

We have also noticed is that even the moon and starlight generates volts - at 8.30p.m. last night 8.6 volts was incoming.

Just Me - thank you for your e-mail - I'm very grateful for the education.  Should the occasion arise in future, feel free to comment on my blog - that way everyone can learn from my mistake :)  But, I reckon it's just as well that RMan is in charge of the power generation...

In for a penny,,,

Following my last posting on our solar panel upgrade and installation, I thought I should give you a peek into our new power room, which is located in the southern side (the cooler side in the Southern hemisphere) of our *new* garage :)  Our old setup with the 4 X 130Ah Deep Cycle batteries did what was required of it i.e. run the alarm when we were not here, and kept our little bar fridge more or less in working order.  But the batteries were too damaged to provide us with anything like the power we needed now that we are living here permanently.  

Inadequate power set up, comprising of
4 X 130Ah Deep cycle batteries,
distance from the solar panels to the
inverter was too far (= loss of energy
capture) and the Phocos 40 amp solar power
charge controller which was too weak to handle
the job we gave it. Seriously, we melted the thing!

We were using roughly 15.5 KwH / day in our town house or 465 KwH / month. That was costing us ZAR1.18 / KwH or ZAR625.52 / month (incl. V.A.T.).

With that in mind I took a snap of the Owl electricity monitor at exactly three months use (to the minute LOL - no, I'm not OCD - I just wanted to give you an apples for apples comparison, and "to the minute" was exactly when we arrived on the farm on the 29th June 2012.)

Our Owl shows that we :
are currently using 139 watts of power at 20.44h
the internal temperature is 16.5 oC
- and - most importantly,
we have used 150.88 KwH since we
arrived on the farm on the 29th June 2012

Here, being more aware of what power we have available, and ensuring that everything unnecessary is switched off / unplugged when it is not required / being used (that includes your iPhone charger, RMan! ;) ), we have, via our solar power, consumed 150.88 KwH in three months, or 50.29 KwH / month.  Which would have cost us ZAR59.34 month.  And 50.29KwH is roughly 10.54% of our normal monthly electricity bill.

Our Cotek 1000 watt inverter, although small,
is sufficient for now, but in hindsight we should've
purchased a 2000watt inverter.  All green lights =
input load is sufficient, battery charge is sufficient
and output load is good :)

With that calculation out of the way, I can now tell you that, at our current usage, our solar panels will be paid off, via our savings on our electricity bill, in 74 months (6.18 years) without any further electricity price hikes being taken into account.  And, bearing in mind that Escom wants to whack South Africans with a 15.11% price hike for the 2012 / 2013 period, I am hazarding a very safe bet that our panels will definitely be paid off faster than the 6.18 years.  From that moment on our power is "free-er" :)

As you can see from our new
Outback charge controller,
we currently have an input of
74.2 volts (8.7Amps)
and the output is 13.5 volts
(40.2Amps).
At 14.4 volts (the way I
understand it) the batteries "float"
i.e. they automatically equalize their
charge. You can also see the solar
panels have generated 1.8 KwH thus
far today (12.30p.m.) and the batteries
are currently being charged with 540 watts 

As far as replacement costs are concerned, the solar panels have a guaranteed lifetime of 25 years, and the 6 X 2volt batteries for 7 -10 years (depending on how you take care of them (top up the water when required, watch the output load, etc)).  When it comes time to replace these items, their costs will, hopefully, have come down quite substantially.  Solar panels currently cost ZAR11 - 14 / watt in South Africa for poly crystalline panels.  Apparently. those in the solar panel manufacturing industry are aiming to get the cost of solar panels down to below ZAR8.20 ($1.00) / watt!  

Our new solar power wiring diagram:
this photo illustrates how our solar panels
are connected to the charge controller
(not shown), and the 2 volt batteries
are connected to the Outback charge controller
and the Cotek inverter.  The yellow and orange
screw caps (floater things) on top of the
batteries indicate the health (water level) of the
batteries.

What we purchased was this:

5 X 135watt solar panels
6 X 1188Ah 2volt batteries which we have linked in series to give us 12 volt
1 X Outback 60Amp charge controller
and add all that to our existing 1000watt Cotek inverter 

We subsequently returned the 3 X 85watt solar panels which we had purchased for our neighbour, and which he didn't want, and exchanged them for another 1 X 135watt panel, which we are going to use in conjunction with the 4 X 130Ah Deep cycle batteries and a water pump - to occasionally, and when necessary, move the water from our rain water barrels next to the house, up to water storage tanks which will be located at the top of our property.  More on rain water storage later...

Our 6 X 1188Ah 2 volt batteries are wired in
series to make up the 12 volts we require.
Please note that this is how we were advised
to wire up our batteries.  Please check with
your local solar power agent regarding your
specific wiring requirements

Now, I realize that not everyone can afford to lay out a fair whack of money in order to get off the grid.  But, by taking baby-steps, savings are possible through investing in some solar powered lights - both for internal and external use), unplugging all those chargers which come with all those fancy new must have gadgets, switching off your power hungry hot water geysers and only switching them on for 1/2 hour prior to using them (or, if you can afford it, changing to a solar powered geyser), and ditching your electric stove / oven and using the sun to cook 95% of your meals :)

Which reminds me, my Sun Cook solar ovens order is on it's way from Portugal, so, not too much longer to all of you who have ordered one... :)