Hello everyone,

I'm helping to build a drip irrigation system for mango trees garden in Cambodia.

There is no electricity in that area and the only water source is a large pond.

The land size is 7 hectare. I want to automate the irrigation process by connecting the solar pump directly to the drip irrigation system.
Also, i'm planning to use solenoid valves to split the territory into 3 areas.

I made some calculation and what I need is 5 m3 water pump working from 1750W solar panels. I need this pump to work 4-5 hours a day.

My biggest concern is a cloudy days. Does someone have an experience using a solar water pump on large territory?
Is it going to work fine or I still should use batteries?

Thanks in advance.

I would keep batteries for those cloudy days, otherwise, as long as there is enough power to activate the pump and valves it should work fine.
If you don't want or have batteries for energy storage, perhaps having the pump fill a tank would be an option for those days without sunshine.

Redhawk

I would try elevating water. Find a solar pump  operate it at full power and fill an elevated tank or a lined pond on a hill. Size it for a few days reserve. That way your only high tech is the pump the rest is gravity.  Drip irigation does not require much pressure you will get 1 psi for every 2.3? Ft of elevation on the tank. So roughly 10ft elevation will give you 4 psi which should be enough. A simple solenoid system could activate your different gravity pressured zones from there.
Sounds like a fun project.
Best regards, David Baillie

After having sold and installed some solar water pumping systems, the batteries will be expensive and unnecessary.  It's easier to oversize the solar array to have some water production on cloudier days.

Play it by ear and expand as necessary if you don't have enough water.  Also, pay attention to the necessary PV voltage to work the pump.  You don't want to have to buy 4-10 more paneles to meet the voltage requirments.  

Drip irrigation is a very simple setup for solar water pumping. Just connect the drip hoses directly to the pump and let the pump irrigate everyday.  No tanks are necessary.  I recommend a Lorentz brand pump which should be sold in Cambodia.  They're higher quality and more expensive, but they save money in smaller diameter drip hoses, solar panel wattage, and overall expenses.  Parts are available and necessary accesories are  also included for long lasting installations.

Jonathan Williams wrote:After having sold and installed some solar water pumping systems, the batteries will be expensive and unnecessary.  It's easier to oversize the solar array to have some water production on cloudier days.

Play it by ear and expand as necessary if you don't have enough water.  Also, pay attention to the necessary PV voltage to work the pump.  You don't want to have to buy 4-10 more paneles to meet the voltage requirments.  

Drip irrigation is a very simple setup for solar water pumping. Just connect the drip hoses directly to the pump and let the pump irrigate everyday.  No tanks are necessary.  I recommend a Lorentz brand pump which should be sold in Cambodia.  They're higher quality and more expensive, but they save money in smaller diameter drip hoses, solar panel wattage, and overall expenses.  Parts are available and necessary accesories are  also included for long lasting installations.

Jonathan, What would be a reliable sources that you could give for such a solar pump system?  I am looking into a system where there are a few options I am interested in. One is a solar pump that will only have to deal with about 5' of head to get the water up and into a cistern.  From there a seperate system would pressurize the tanks/house.  The stepup option for this is for that pump to be part of a system that includes batteries so it can run 24/7, and then I would use the water overflow to regulate/insulate the supply line to prevent freezing.  Essentially water would be in a continuous loop with the pump putting water into the cistern through a supply line that is surrounded with water returning to the spring sump from the overflow of the cistern.

What do you think?