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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.


 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.

  1. A normal Farmhouse with a 3-5 Kw generator, one freezer, maybe a fridge,  an iron and other domestic appliances, small tools.  Freezers and fridges should be the cold bank or energy efficient type.


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

  1. A large household with a 5 Kw engine or larger, freezers, fridge, microwave, air conditioner, large equipment and waterpump.

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


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


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 :

Price including stiffy for Computer Programme                    R 1 950,00 + VAT


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.


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.




 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.


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.


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.


MPPT = Maximum Power Point Tracker - Micro processor controlled. Originally designed by me for the Shurflo solar pump.  May be used with any DC motor for best results.

It protects the solar pump against high voltage and short circuit.  It stops the pump when the borehole is empty or when the reservoir is full, thus  lengthening the lifespan of the pump.  The biggest advantage is that it delivers the most water under all circumstances. 

In order to understand the MPPT, one should compare it to a motor car gearbox.  The volts and amps of the solar panels and pump are continuously controlled by the micro processor, with more than 200 “gears” to select from.  It delivers up to 30 volt irrespective of the input voltage. 

It is thus possible to pump at 24 volt with one panel.