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WHERE DO I START
Looking
at the variety of solar systems available, you may wonder how on earth could one
select the best system for your needs.
Then
the stories about systems failing, agents coming and going, products
disappearing from the market, electronic equipment which cannot be repaired
after it’s guarantee, very expensive systems which do not save you a cent.
There
are a few basic rules which apply to all solar systems :
a)
The
most important is that you as the consumer
must grow into your system. Unlike Escom it is not a matter of writing a cheque and
pressing the button.
b)
Escom
is trying very hard to convince people to save power – effective use of
energy. Due to the high costs of
alternative energy, it is imperitive to use energy effective appliances. And save where ever possible.
c)
Trying
to save by buying cheap products simply means that you’ll have to pay for
unnecessary repairs and replacements in the long run.
For example :
It does not help to use a good inverter on weak
batteries. The inverter cannot hide
the faults of the batteries.
d)
The
first and most
important is to get the correct
information when planning your
system.
e)
The
first buy is the most
important. The very first
investment in alternative energy should be a battery charger, good batteries of
adequate capacity and an automatic sinewave inverter.
1.
BATTERY CHARGERS
To
charge batteries from the engine’s 220 Volt.
Constant
voltage, constant current is the best way to charge batteries.
This means that the charge rate as well as the voltage is electronically
controlled to prevent damage
to your batteries. Yet it
charges quickly so that the engine does not run unnecessarily long.
A good battery charger consists of more than just a transformer and
diodes like some on the market today.
The suggested rate of charge for tubular cell batteries is 20% of capacity.
It
is the heart of the entire system. Cheap
batteries have caused many a solar system to fail.
We
suggest 400 amp hour capacity for a household.
For
larger systems use 2 x 400 amp hours. The
advantage of glass cell
(poly
prop) is that you can see when water is needed. If battery cells run dry, it can never be repaired.
Sediment is a good indication of the condition of a battery.
We
have designed a battery logger
which indicates the condition of each cell.
See No. 5 below. With this
new logger it becomes a proposition to buy second hand batteries.
You can clearly identify weak cells and replace them in time.
3.
INVERTER
It
does not make economical sense to buy an inverter which cannot replace the
engine, except when water is pumped on a daily basis.
Our
new 2.5 KVA is quite sufficient for household use.
It can handle fridge, freezer, microwave, large tools etc – but not all
at the same time. The
4
KVA can handle 3 freezers, swimming pool motor, waterpump as well as large
equipment and tools.
Fridges
and freezers are the worst enemies of any solar system.
When using cold bank type try to run the one after the other while the
sun shines. It is more efficient to
use the power from the sun directly – it also saves on battery life.
Most
important : use energy efficient fridges and freezers.
Try
not to draw more than 10% of the battery capacity continually.
For
short periods, a battery can deliver up to 50% e.g. to start a motor.
It
is a pity that squarewave inverters are still being manufactured.
With modern technology of P.W.M. (Pulse Width Modulation) sinewave is
just as efficient as squarewave. When
electric motors are run, the sinewave is even more efficient than squarewave.
Semi
sinewave, trapeze wave and modified sine are also squarewave.
Most inverters sold by chain stores are squarewave.
With
the latest technology Mosfets are used instead of transistors to drive the
inverter. This makes the inverter
even more efficient. Previous
sinewave models can be rebuilt at a reasonable cost.
You
should get 20 years service from your inverter and solar panels and at least ten
years from your batteries. Why buy
anything but the best. If your
system fails, you will have only yourself to blame.
A
solar system without a reasonable engine and a good battery charger is too
risky.
40 Amp 36 Volt Battery Charger
R
5 550,00 + VAT
210 Amp hour Glass batteries (Willard)
R11 250,00 + VAT
2.5 KVA Sinewave inverter R 6 550,00 + VAT
80 Amp Battery Charger Single Phase
R 6 550,00 + VAT
420 Amp hour Glass batteries (Willard)
R18 950,00 + VAT
4.0 KVA Sinewave inverter
R 7 550,00 + VAT
or
6.0 KVA Sinewave inverter
R 8 950,00 + VAT
120 Amp 3 Phase Battery Charger
R11 950,00 + VAT
200 Amp 3 Phase Battery Charger
R15 650,00 + VAT
4. AMP
HOUR COUNTER
What
a frustration to try to determine how much power is left in your battery at a
certain stage. It is impossible to
guard the ampere meters all day.
A
sophisticated instrument which counts each and every amp being charged into the
battery and at the same time deducts each amp used by the inverter or 36 volt
lights.
The
balance on the counter is what is left in the batteries.
If
the counter indicates an abnormal balance while the batteries are flat, you must
check the efficiency of your batteries. Maybe
one or two cells are dead. Check
for loose connections.
Very
important : You must charge 20% more than what you take out – this accounts
for the normal shortfall on the meter.
Also
reads volts and ampere in and out of the battery. Which means you do not need an ampere meter for the solar
panels or windcharger. Neither for
the inverter. Very easy to install.
The same functions built into the Universal monitor.
See No.7 below.
12,
24, 36 or 48 Volt DC
R 965,00 + VAT
5.
BATTERY LOGGER
A
dead battery looks exactly like a new one.
The
difference between a dead and a flat battery can only be determined through
intricate tests. Coupling 2 volt
cells in series to supply 24/36 volt in alternative energy systems the problem
becomes more complicated because each cell is actually a battery on it’s own.
To
overcome this problem, we have designed a battery cell logger which indicates
precisely the condition of each individual cell in the battery system.
Seeing that each individual cell is tested regularly, you can monitor the
voltage of each cell while it is being charged or discharged.
A weak cell can be identified immediately and replaced.
In most cases, batteries fail due to one or two bad cells.
The
logger stores details of 3000 individual readings. Can be down loaded into a PC.
Printout reflects voltage of each cell and time of reading.
You can now keep permanent record of daily movement of cell voltages –
even for years.
Send
the printout or e-mail it to me for free advice regarding your batteries.
E-mail address : nelson_adams@xsinet.co.za
Price
including stiffy for Computer Programme
R 1 950,00 + VAT
6.
UNIVERSAL VOLTAGE REGULATOR
A
battery can be damaged in two ways :
1)
Overcharging
for long periods.
2)
By
leaving it in a discharged condition, even for a few days.
Should
the voltage rise above the full level (say 42 volt), a dummy load on the
batteries gets rid of the excess power. The
volts is kept constant at a preset level, without disconnecting the chargers
(solar or wind). The maximum
voltage can be set on site.
A
relay switch to start a waterpump, geyser etc before the batteries are full, is
optional.
Price R1 350,00
+ VAT
Important
:
My
inverter stops working before the battery voltage reaches a dangerously low
point. If this happens, please
charge your batteries to at least 50% full before using the inverter again.
The
surest way of destroying a battery is to drain it, charge a little, drain flat
again, little charge, drain flat. This
process destroys a good battery within months.
7.
UNIVERSAL MONITOR
Complete
monitor for your power system.
The
following readings are shown on one meter :
1)
Engine (or
Escom with UPS)
a)
AC
Volts
b)
Hz
– cycles. Indicates speed of
engine.
c)
Total
running time.
d)
How
many times the engine started.
e)
Current
running time.
2)
Inverter
a)
AC
Volts
b)
Hz
c)
Total
running time.
d)
How
many times switched on.
e)
Current
running time.
3)
Batteries
a)
Volts
b)
Amps
charging or discharging (-)
c)
Time
charged
d)
Time
discharged
4)
Amp hour counter.
The same functions as above – see No.5
5) Maximum. Of certain readings are recorded
The Amp hour counter and maximum readings can be
cancelled.
Very easy to install – only three wires and a
shunt to connect.
8.
SOLAR PANELS
Do
not replace your engine immediately. Use
it to charge batteries.
Later
add solar panels and or a windcharger to charge the same batteries.
This way the engine runs less untill you need it only as a standby.
Since
solar panels appeared on the market in South Africa in about 1980, a variety of
makes have come and gone.
The
most common weak point of solar panels is that the voltage drops in our
extremely hot climate. They work
quite well in Europe and Japan where it does not really get hot . Solar panels perform best in icy weather with bright sun.
With less than 36 cells in a 12 volt panel, you can be sure the voltage
will be too low for the warm areas.
9.
WINDCHARGERS
Since
the days of the 6 volt wireless, windchargers were well known on farms.
The old Windchargers, Wind Power and Jacobs were the most popular.
32/36 Volt models were imported up to 1952 to charge batteries for
lights, 32 volt appliances and tools.
Hundreds
of the old machines are still in excellent working condition.
For
example, Kallie Theron of Richmond with three old windchargers supply enough
power for his entire household with all appliances as well as tools.
See
Farmer’s Weekly 12/02/82 and 03/09/83. Under
the Escom pool system, he also got power. 2
Km free power line. R60 000,00
which he does not have to repay. (2000
Quote : R65,000 per Km).
See
Whisper pamphlets enclosed. We now
have more than 250 of these machines operating on farms.
The
same machine can charge 12, 24, 36 or 48 volt batteries.
We
have proved beyond any doubt that a 3 Kw windcharger supplies enough power for a
normal household including fridge and freezers.
At
about R 45 000,00 + VAT it may be a good investment in windy areas.
10.
THE WATERPUMP REVOLUTION
The
windpump has been known to us for more than 200 years.
The
Egyptians had probably used the wind to move water and grind corn long before
that. Problems with no wind
conditions, storms, wear and tear, corrosive water and replacing corroded pipes
made the windpump very expensive and very unpopular, because nobody wants to
work anymore.
Solar
pumps have been imported for quite a while, as well as manufactured locally.
Some do not last long, others are too expensive.
Some work with inverters and batteries.
The Shurflo 9300 is imported from USA and built lo last for many years.
Being a DC motor, brushes have to be replaced regularly.
Price
of pump only
R 3 950,00 + VAT
It
is thus possible to fully service a borehole for about R 6 000,00.
For
example : At 15 metres a 40 watt panel (R1 350,00 + VAT) delivers 200 litres per
hour – enough for 250 sheep.
See
Shurflo pamphlet for delivery rate at various depth, with one or two panels (12V
or 24V).
N.B.
It is always best to install a regulator with any solar pump.