Solar Water Well Pump
The Solar Powered Well Pump

The solar water well pump is a submersible well pump powered by solar panels that can be optionally backed up by deep cycle storage batteries. It is advisable to pump into a storage tank during daylight, the stored water can be used over night and over cloudy days. Solar well pumps are the modern age solution for pumping irrigation water and drinking water from remote unattended wells

Wells, Well Pumps and Solar Powered Well Pumps

The technology of drilling wells to reach underground water was known in ancient days. The Bible tells us fascinating stories about wells (beer in Hebrew) and Beer-Sheva (literally the well of the seven) is a modern big Israeli city built on the historical location of the ancient Beer-Sheva.

Picture attributed to dionhinchcliffe's photostream

The technology of bringing the water to the surface and filling up water reservoirs or cisterns developed over thousands of years. The principle remained the same; water naturally flows from a higher altitude to a lower altitude. If you want to bring water up from a lower altitude to a higher altitude you need to invest energy in one form or another. The energy source evolved from people pulling buckets from the well, to oxen driven mechanisms through windmills and finally with the advent of electricity to using electric water well pumps

The next logical step is to use solar panels to provide electricity that powers the water well pump

The Advantages of the Solar Well Water Pump

The main advantage of the solar water well pump is for remote unattended locations. Once you install the correctly sized solar kit you can expect an uninterrupted smooth water pumping. For a convenient and an efficient operation, add a smart monitoring system connected via wireless data line to where you stay most of the time. Typical locations are wells or ponds serving livestock drinking facilities, remote field irrigation or water wells for the residents of off the grid living.

Another advantage is economical, solar energy is practically free of charge

Like all other off grid solar power generators, solar water well pump requires very little maintenance. The solar powered generator is robust and can last two decades or more.

DC or AC Solar Well Water Pump

Solar panels convert sun radiation to DC (direct current) electrical power. Solar panels have a specified output voltage and a specified wattage (power delivery capacity) rating. Choose either 12V panels or 24V panels to match the submersible well pump you use. I’ll discuss the required size in a subsequent paragraph. In case you have an AC pump and you don’t want to replace it with a DC pump, you’ll need to add a a pure sine wave DC to AC inverter. The pure sine wave inverter is usually more expensive than the DC pump.

how to convert existing electric water well to a solar water well pump?

The size (Watts rating) of the panel needs to match the size of the solar water well pump. I assume the pump is sized correctly to deliver the required flow (specified in gallons per minutes or litters per minute) to the required head (specified in feet or meters). Look at the power rating of the pump in watts, that is what you need from the solar panel. For most situations, 130 Watts panels or two 60 Watts panels will do the job.

If you start from scratch (new well), you need to calculate the size of the pump first (opt for a DC pump) based on the head and flow. Then, size the solar panels accordingly.

DC operated well pumps, like other DC operated motors has a higher rush in start-up current than the current they require during normal operation. This rush in current if drawn directly from the solar panel will cause the panel delivered voltage to drop bellow the required voltage for the pump. To overcome this problem, use a pump controller between the solar panel and the pump

The Complete Solar Well Water Pump kit

A complete solar water well pump kit will have the pump, the solar panels, the pump controller, two float switches (one for highest allowed water level and one for lowest allowed water level) in the cistern with electrical wiring to the controller, smart monitoring and a wireless data link.

Rather than adding expensive and relatively shorter life storage batteries, store the pumped water in a larger reservoir to accommodate for night time and cloudy days. You may assume 5-6 hours of useful sun radiation on the average in 24 hours, therefore calculate the size of the pump accordingly. Divide your 24 hours water consumption by 5-6 to get the pump size needed to deliver this amount of water. The reservoir should be big enough to store water for 48 hours to store water for cloudy days.

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