Frequently Asked Questions (FAQ's)

About Solar Pumps

How do solar pumps work?
What happens when it's cloudy?
How reliable are solar pumps?
Who can benefit from solar pumping?

About Lorentz

How much total dynamic head can a Lorentz pump do?
How much water can a Lorentz pump?
Do Lorentz pumps use batteries?
Are Lorentz pumps suitable for liquids other than water?
What kind of weather conditions can a Lorentz pump stand?
How much does a Lorentz pump cost?
What kind of maintenance does a Lorentz need?
How long will a Lorentz pump last?
Do Lorentz pumps come with a warranty?
Where do I go to buy parts for my Lorentz pumps?
My Lorentz isn't pumping as much as I expected. How can I get more water out of it?
Can I have my Lorentz pump turn off automatically?
What is the difference between a fixed and a tracking array?
What effect does adding a tracker to my array have?

About Rebates

Am I eligible to receive a government rebate when I buy a Lorentz pump?

About Installing

Where should I install my solar array?
Does my solar array need to be on a pole?


What is total dynamic head? Why is it important?
What is insolation?
What is voltage?
What is current?
What is power?
What is a kilowatt-hour?
What is the difference between connecting panels in series and parallel?




How do solar pumps work?

A solar pump is essentially an electric pump attached to a standalone power supply. There are generally four parts:

  • A 'wet end', which is the mechanical device that moves the water. Lorentz pumps utilise three types of wet ends;
    a) helical rotor
    b) centrifugal
    c) rotary vane.
  • An electric motor, which transforms electrical energy into rotary motion. The electric motor is connected directly to the wet end. For submerged pumps, this means that the motor is of a special submersible type.
  • A control which helps to keep the motor running during low sunlight and allows fitting of automatic switches for low water protection and tank full situations to automate your water system.Solar array which consists of;
    a) Solar panels, which transform sun light directly into DC electrical energy and
    b) A solar array, either tracking or fixed, upon which the solar panels are mounted.


What happens when it's cloudy?

When clouds pass in front of the sun, the intensity of light falling on the solar panels decreases. The solar panel will not be able to produce as much power as during full sun. This is the reason for the pump control  - it senses the drop in power caused by a cloud, and reduces the current the motor draws to keep the maximum amount of power flowing.

Controllers are essential for most solar pumping systems because they maximise the power from the modules going to the motor. Acting like a gearbox in a car, they vary the current to the motor in the same way a gearbox varies the revs to the wheels. The pump will continue to work at a lower speed but water will still be pumped.

Under all but the heaviest of clouds, your pump will continue to function. As a general rule, if there is enough sunlight to cast a shadow then there will be enough power for the pump to run  only with a reduced flow rate. Pumps with helical rotor wet ends are particularly good at operating under cloud or low sunlight conditions.


How reliable are solar pumps?

Solar pumps are being recognised as achieving  "gold standard reliability" for moving water. The design of a solar pump minimises moving parts. By minimising moving parts wear is localised to just a few components and breakdowns become very infrequent. This means that a solar pump, once set up correctly, can run for many years with minimal intervention. This is not to say that they require zero maintenance: it pays to periodically check your solar pump components for wear and replace them before a breakdown occurs.


Who can benefit from solar pumping?

Solar pumps can benefit anyone who regularly needs to move significant amounts of water, without having access to metropolitan or town scheme water. This may include homeowners on rural or semi-rural properties, farmers who need to water livestock and irrigate crops, small communities that may wish to raise their water supply to improve pressure and nowadays mining and industrial applications are becoming more frequent. Solar pumps see service in all of these scenarios and more.Who is Lorentz?

LORENTZ is a global leader in solar-operated pump systems and considered one of the leading manufacturers in the field. The German engineered range of pumps is regarded as having superior quality, durability and efficiency. Our local service partners maintain a close link to the customer and guarantee professional support, installation and maintenance.


How much total dynamic head (TDH) can a Lorentz pump do?

There really is no limit except for the cost. The different Lorentz models have different capabilities. In general, there is a compromise between the head that is required to be overcome and the amount of water that can be pumped during a period of time. The Lorentz pump portfolio spans a nominal power range from 0.15 kW to 21 kW, covering lifts of up to 350 m and flow rates of up to 130m3/h.

 In practice, you are not limited by the amount of TDH you need to overcome. To pump higher heads, multiple pumps can be daisy-chained together.


How much water can a Lorentz pump?

The amount of water that a Lorentz will pump depends on the pump model and the total dynamic head (TDH) that needs to be overcome. To find out exactly how much water can be pumped in your application, contact your local Lorentz dealer.


Do Lorentz pumps use batteries?

The use of batteries with solar pumping systems is avoided. Batteries are inefficient, expensive and can significantly increase the cost of a solar pump system. Batteries prefer constant temperatures to get the best life out of them. In the remote locations solar pumping systems are used expensive enclosures are required to keep temperatures constant. Often it makes more sense to invest the money spent on batteries and enclosures on additional tank capacity that can be drawn upon through the evening.

 Some Lorentz systems utilisetracking systems. Trackers are powered by a small 12 volt battery which are trickle-charged by the solar panels. Tracking system batteries tend to enjoy long life, as they are rarely discharged more than a few percent from maximum capacity.


Are Lorentz pumps suitable for liquids other than water?

We do not recommend using a Lorentz to pump liquids other than water. Corrosive liquids will degrade and eventually destroy your pump. Highly viscous liquids such as oil can foul the pumping mechanism and significantly reduce performance.

You may use a Lorentz to pump to move brackish or dirty water, however you may reduce the pump's life by doing so. If you must pump water containing particulates, we recommend performing more frequent maintenance. If you have any concerns regards water quality contact your nearest Lorentz dealer to assess your application.


What kind of weather conditions can a Lorentz system withstand?

Lorentz pumping systems are designed to operate out in the open, under intense sun or heavy rain, or in high winds for years on end. All materials used in the construction are suitable for many years of operation in the Australian environment.

Should you be in a cyclone zone or extreme weather area consult your Lorentz dealer for information specific to your requirement.


How much does a Lorentz pumping system cost?

There are many different pump packages available to suit your water pumping needs.System costs start from $2000. The benefit in installing a solar water pump is that the upfront costs are once-off, with very little ongoing costs. This compares favourably with diesel or petrol-powered pumps in the long term - they have low up-front cost but incur very significant ongoing costs.  Solar panels have halved in cost in the last 12-18 months and it is anticipated that panel costs and solar pumping equipment will continue to decrease as the uptake of these items continue to increase. When was the last time you heard fossil fuels will become cheaper? How can you afford not to have a solar pump?


What kind of maintenance do Lorentz pumps need?

Maintenance schedules vary depending on the duty and water qualities involved. Submersible pumps will benefit from being removed from the bore and checked on an annual basisOnly the mechanical parts of a solar pump require maintenance. The solar panels and electronic components are maintenance-free: you can expect your solar panels to deliver power reliably for over 25 years without any form of maintenance being required.

Most solar pumps work for around 2,500 hours per year. Maintenance cost depends on the size and type of system -you should allow $ 200.00 to $ 500.00 per annum over the life of the system for replacement of system components as they wear.


 How long will a Lorentz pump last?

Different parts of your pump will have different life spans. The solar panels are designed to last for over 25 years before needing replacement. Electronic components will last at least 10 years. Mechanical parts will require regular replacement of bearings and bushings around every 5 years to maintain optimum operation.


Do Lorentz pumps come with a warranty?

Lorentz pumps are sold with a 24month warranty on parts.


Where do I go to buy parts for my Lorentz pump?

Lorentz replacement parts are available from dealers located across Australia.Solco carries acomplete stock of Lorentz components and spare parts. We have distribution centres in Perth, Melbourne and Brisbane.


My Lorentz pump isn't pumping as much as I expected. How can I get more water out of it?

In most instances, more water can be pumped by increasing the solar power installed - adding more solar panels. Whether your pump can be upgraded depends on the model and the way it is configured. Often, adding an incompatible component to your pump can degrade performance instead of enhancing it. Locating the bottleneck in your pumping system is a job for experienced personnel - we strongly recommend that you contact your local dealer to discuss your needs before attempting to reconfigure your pump.


Can I have my Lorentz pump turn off automatically?

Yes. All Lorentz pump systems are supplied with a lowlevel switch to sense when your bore or water supply runs dry, protecting the pump. Additionally, you may wish to include a tank-full mechanism that senses when the delivery tank is full, again turning off the pump. These mechanisms automatically allow the pump to restart when the water level leaves a full or tank or returns to an empty water source.


What is the difference between a fixed and a tracking array?

A tracking solar array changes its angle in an east-west direction throughout the course of the day so that it faces directly at the sun at all times.

The amount of power produced by a solar module is affected by the angle that the light hits the surface. When light hits the solar cell surface at a low angle, it is more 'spread out', so that less light falls on the array's surface area. A tracker ensures that light always falls on the array at the best angle possible.

A fixed array does not adjust its angle dynamically. A fixed array may, however, be angled in a north-south direction towards the sun's winter or summer path through the sky and adjusted manually (2 or 4 times a year) to catch the sun better at these times.

Tracked arrays require fewer solar panels to output the same amount of energy over the course of the day compared to a fixed array. This reduces solar panel costs, however there are initial and ongoing costs associated with fitting and maintaining the tracking hardware.


What effect does adding a tracker to my array have?

Tracking arrays produce more power and thus more water as compared to fixed array of the same size. In bright sunlight a tracking array can provide up to 40% more power over the course of the day. The difference is most notable in the morning and afternoon: the water pump will start pumping earlier and finish pumping later, and pump greater volumes during the early and late hours.

Trackers are less effective in cloudy weather: the cloud diffuses the incoming sunlight, which hits the array from many angles at once instead of from a single bright spot in the sky.


About rebates

Am I eligible to receive a government rebate when I buy a Lorentz solar pump system?

The federal government encourages the use of renewable energy systems in areas off the main power grid and may provide a rebate for your Lorentz pump system. The rules surrounding the rebate program are detailed and will not apply to all solar pump installations. We urge you to visit ORER and read the rebate guidelines to determine whether you qualify.


About Installation

Where can I install my solar array?

The sun powers your pump via the solar array. If your array falls under shade at any time the power it can produce will be markedly reduced. Shade on even a small part of the array will reduce power disproportionally and may cause the pump to stop working. For this reason, your array should be sited in an area that is guaranteed to receive sun for as much of the day as possible, all year round. Take note of the location of trees that may grow tall enough to shade the array in the future and locate the array accordingly.

Try to find a location for the array near the pump motor, but note that the array does notneedto be sited near the motor. The array can be located hundreds of metres away from the pump , but electrical wiring will need to be sized carefully so that power is not lost in transit - volt loss. The further your array is from the pump motor the higher gauge wire you will require, and the cost you incur will rise accordingly.


Does my solar array need to be on a pole?

Your solar array is mostly mounted on a single pole due to ease and speed of installation, to have above the height of most stock, and to raise it above growing vegetation. If the array tracks the sun, the pole is also required to provide a range of movement. Your solar array should always be fenced to keep stock away.

A thin film of dust on your solar array will not significantly affect its operation. Rain, especially on dry ground, kicks dust into the air in thick globules that will affect your solar array's performance if allowed to accumulate. The pole raises the array above this airborne dirt, representing a maintenance-free way of keeping your array clean.


Do I need to adjust my solar array with the seasons?

Whether you adjust your array seasonally depends on your water needs. Most arrays will be tilted in a north-south direction to provide the best flow for summer (this will be 10° from horizontal from low latitude up to about 33° latitude and will vary at higher latitudes), because that is when most people need water the most. This tilt angle does not provide the best flows in winter, however, and some applications require a more consistent year-round flow. There are a few different ways to manage seasonal sun-angle variation:

  1. Maximise summer flow: tilt your array to the noon angle of the summer sun and leave it. This provides optimal water flow during the summer, but reduced performance during the winter.
  2. Maximise consistency: tilt your array to the noon angle of the winter sun and leave it. This provides optimal water flow during the winter when the sunlight is weaker. Summer performance will be reduced. This combination of raising winter flow and reducing summer flow provides the most consistent water flow throughout the year.
  3. Maximise year-round flow: adjust the angle of your array periodically. It is not necessary to adjust the array more than 4 times a year and for most purposes twice a year is adequate. Adjusting the array more often provides diminishing benefit. For twice per year adjustment move the array between the winter and the summer angle around the time of the autumn and spring equinoxes (the end of March, and the end of September). For four times per year adjustment move the array from summer to equinox angle around the end of February, from equinox to winter angle around the end of April, from winter back to equinox angle around the end of August and from equinox to summer angle around the end of October.
  4. Compromise: tilt your array to equinox angle and leave it. The equinox angle is the same angle as your latitude.

Note: we have used "summer", "equinox" and "winter" angles here - the exact angle depends on your location.



What is total dynamic head? Why is it important?

Total dynamic head (TDH) is a measure of how much force your pump needs to exert to move water. TDH is a combination of hydraulic head and friction loss.

Hydraulic head is the force required to lift water against gravity. Water in any section of pipe is weighed down by all the water above it. The further your water inlet is below your outlet, the more hydraulic head (measured in metres, kilopascals or pounds per square inch) needs to be overcome.

Friction loss refers to the fact that as water moves through a pipe, it has to slide along the walls of the pipe. Although water is slippery, there is still some friction to be overcome. The smaller the pipe diameter, the faster the water is moving. Therefore, more friction loss is experienced and the pump requires more power to operate effectively. The situation is complicated by turbulence in the water at high flow rates, and the presence of any elbows in your pipe system, where water must change direction quickly.


What is insolation?

Insolation is a measure of the intensity of sunlight, and this light intensity is converted directly into electric current by solar cells. The figure commonly quoted is that 1000 watts of light power fall on every square metre of ground. This is not the case for most locations at most times. Latitude, time of the year, time of the day, shade and cloud all have an effect on insolation levels in your location.

When you specify a TDH and flow level required for a solar pump, we use the Bureau of Meteorology's average insolation figures for your area to figure out how much solar power to include to meet your needs.


What is voltage?

Voltage is a measure of how much energy an electric current has.

Electricity is essentially a flow of electrons. You can think of it as a flow of water. When electrons have high energy they are said to have high voltage. High voltage electrons are able to travel more easily through a conductor such as a wire or the windings in a motor, producing larger currents and more power.


What is current?

Current is a measure of the rate of flow of electricity.

Electricity is essentially a flow of electrons. You can think of it as a flow of water. Current is a measure of how many electrons are travelling through a wire at any one time. Thinking of water, a low current is like a creek, where high current is like a river. Higher currents correspond to higher power in electrical devices.


What is power?

Power is a measure of the rate of energy conversion.

Electricity is essentially a flow of electrons. Every electron has energy, called the voltage. The amount of electrons flowing is called the current. The energy (voltage) in each electron added up for all the electrons in an electric current tells us how much energy the current has as a whole. Power is a measure of how much of this energy moves through a device every second.

A motor, for example, converts the energy in an electric current into rotary movement. The amount of energy it converts every second is the motor's power consumption.


What is a kilowatt-hour?

A kilowatt-hour is a unit of energy.

Power, or energy converted per second, is measured in watts. A kilowatt is 1000 watts, which is roughly the power consumption rate of devices like electric water heaters, fridges, microwaves and kettles. A kilowatt-hour refers to a 1000 watt device operating continuously for 1 hour.

A 500 watt solar pump will produce a kilowatt-hour of electrical energy every 2 hours or around 2.5 kilowatt-hours every day.

Energy is often measured in kilowatt-hours because it leads to convenient numbers. For example, we might just as easily measure energy in watt-seconds, but now the solar pump above is producing 9,000,000 watt-seconds of energy per day. Most people find it easier to think in smaller numbers.

If you are on scheme power your power bill will quote the average number of 'units' you use every day. These units are actually kilowatt-hours.


What is the difference between connecting panels in series and parallel?

There are two ways of connecting solar panels together: series and parallel.

When you connect solar panels in series, the positive cable from one panel is connected to the negative cable of another. The voltage of the two panels combined is the sum of the voltage from each panel, whereas the current is not affected.

When you connect solar panels in parallel, the positive cable from one panel is connected to the positive cable of another, and the negative cable is attached to the negative (you will need a couple of double-adapters, as the cable ends are keyed to only connect positive to negative). The two panels together can deliver the sum of the currents of each, though the voltage remains unaffected.

Thus, to increase the voltage of a solar array, you connect panels in series. To increase the current, you connect panels in parallel. Doing either increases the power delivered by the array, since power=voltage x current.

The voltage that a solar array is allowed to deliver is limited by safety concerns. As voltage increases, electricity becomes more dangerous. Thus, cables are often connected in series up to a maximum safe voltage, then to increase power, sets of panels already connected in series are connected in parallel to increase the current the array is able to deliver. Such arrangements are often referred to as 'strings'.

Care must be taking to match panels when they are being connected together. When panels with different current ratings are connected in series, the set will only be able to deliver the current of the lowest-rated panel, which not only wastes power, but may overload the limiting panel. If panels or sets of panels with different voltages are connected in parallel, a current will flow between them, potentially damaging one or the other.