FAQ's - Solar Water Pump

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Why provide reticulated water to livestock?
Replacing streams and dams with water tanks, pumps, pipes and troughs on hill country farms makes the flow of stock water more efficient.

A recent report for the NZ government identifies the following advantages:-

  • Increased stock numbers.
  • Increased lambing (12%) and/or calving percentages.
  • Increased slaughter weights.
  • Opportunistic stock finishing.
  • Saved costs from not having to maintain dams on a regular basis.
  • Economics paybacks from 1.5 years (3 year average over 11 farms)

Note: New NZ legislation will exclude dairy cattle from access to waterways from 2017 and further exclusions will follow in years to come. You will find more information on this matter in the Resources section of this website.

What's in the package?

Here is a list of major components included in the package:-

  • Fully assembled hydraulic pump with pressure gauge
  • Timber frame
  • Saddles and fixing
  • Four PV solar panels
  • PV solar panel mounting set
  • PV solar rated cable
  • Conduit
  • Breaker box and mounting box
  • Pump mounting base
  • Screws and washers, valves, manifolds, some installation tools, fixings, etc.

For a detailed list of parts please refer to Installation manual - Chapter 1.4, page 9

Items that are not provided:-

  • Any civil works
  • Intake screen
  • Pipe
  • Water tanks (header/storage or any buffer tank at intake).
  • Installation service (can be arranged in NZ, ask us to quote you)

How high can the PowerSpout SHP pump water?

The PowerSpout SHP has a maximum dynamic pumping head of 250m. A static head higher than 200m can be successfully implemented.  Seek our advice on heads between 200m and 250m.

How much water can it pump daily?

In Taranaki for example on a typical summer’s day, we can expect about 8000Lt/day to a 100m dynamic head. (90m vertical lift + 10m pipe friction head).
Below is a pump performance table for a New Zealand location in litres/day.

This table may over predict or under predict for your NZ location, it is indicative only.  If your chosen pipe diameter results in more than 10% increase in dynamic head due to friction then performance (for a given head) may be less.
The pump will work fine on heads under 80m, but is never likely to pump more than 10,000 litres per day in summer. Below 80m less power is required so the pump spends more time running at full speed, which is limited by the electronic BLDC (brushless DC motor) speed controller. It is our assumption that most of our customers will wish to pump in the 60-220m static head range.

The maximum flow the pump can deliver is 35 litres/minute at zero head with a 10mm cam fitted and running at 900 rpm.

What happens if there is not enough water for the SHP?

The flow of water through the SHP depends on having water in your resource. If your resource flow cannot keep up with the SHP pumped flow, then the level will fall until air enters the suction line. Once this happens the pump will continue to rotate, but no water can be pumped, as suction prime will have been lost. Even when the water level builds back up over the suction intake, the SHP will not be able to pump as it cannot prime against a full delivery head, so you will need to intervene to manually prime with water. You can avoid this issue by installing a float switch on the ignition wires of the BLDC (Brushless DC motor).  Do not install a switch on the PV supply wires unless it is suitably rated for the 80VDC.  For more details please refer to section 3.5, page 27 of the installation manual.

What happens when the tank is full and I don’t need more water anymore?

Your SHP may pump more water than you need at times. This will cause your tank to overflow, and the surrounding ground may become water logged. Ensure that this overflowing water does not cause soil erosion, and eusure that it gets back to a stream or gully cleanly. We suggest that you install a pipe on the tank overflow fitting for this purpose. This is the best and simplest option for dealing with surplus water. If you have previously used grid electricity or fuel pumps you would normally stop the pump when the tank is full to save running costs. You do not need to do this with solar pumps as sunlight is free and it is better for the pump to run. If you cannot make provision for overflow, then see our guidance in installation manual for tanks that are fitted with "ball valves" (or "float valves").   Section 4.6, page 50.

How can I conserve my water resource?
There will be occasions when your water resource may run dry or the pumping rate exceeds the natural flow rate of the resource. In such cases, you either need to stop pumping or provide a pumping buffer (tank or pond) for the resource to accumulate when the SHP cannot pump. If for example you have a small spring with a dry summer flow of 0.1 Lt/s (10sec to fill a 1 Litre container) then in a day this is 9000 Litres and a very helpful amount on a dry sheep/cattle farm. If we assume you need all this water to be pumped to your tank on a 60m hill each day, then some buffer storage of the water resource is required. Normally this storage would naturally replenish at night when your SHP cannot operate. To stop the SHP, a float switch can be wired to the BLDC (brushless DC motor) driver's "ignition" wire (intended for electric vehicle use). (Do not install a switch on the PV supply wires unless it is suitably rated for 80VDC.) This will stop the pump at the lowest acceptable level of your water intake resource.

Floating switches that are tethered by their own wire can provide a wide, adjustable hysteresis between turning on and off.   Much of the time they float level on the water surface. The switch will not operate until it tilts. If the small spring can be diverted into a pipe and fed by gravity into a 10,000 to 15,000 Litre tank then the outlet of the tank can be connected to the input of your SHP, and is the best solution. If you do not have the fall for a tank, you can excavate a small pond to store about 20,000 litres. Ponds can be a death trap for children and animals, so fence it appropriately. Then you can install an SHP on a small pontoon in the middle of your pond with the suction hose set about 100mm below the surface where UV from the sun helps to sterilise the water being pumped. Design the pontoon structure to sit on the bottom of the pond before the foot valve intake hits the mud/silt level. The pump running dry will do it no harm, but it will need to be primed manually, so you may wish to also fit a float switch that breaks the BLDC driver's "ignition switch" circuit, to avoid drawing air in.

Can I decrease the amount of pumping by turning off PV modules?

Another solution to avoid wasting your water resource when the storage tank is full is to order a dual DC breaker enclosure. If your tank tends to overflow you can then turn off one PV frame and your SHP will pump between 30-40% of the water it would normally pump. You manually turn on the other PV frame when you need more water to be pumped, perhaps when sunshine/days are getting shorter.
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For further details on this NEW SOLAR WATER PUMP please contact:
Independent Power NZ Ltd
32e William Pickering Drive
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