advice on solar powered drip irrigation

Hi all,

I am setting up a drip irrigation system for my orchard/garden that will need 6GPM flow at 25PSI and run for an hour twice a week during summer only.  Rather than digging a well, I will use a 3000 G storage tank filled with rain water that will be above ground, and the area being irrigated is flat. I am having a really hard time understanding and finding a suitable DC pump and solar equipment to meet my needs and keep it at a reasonable budget.

I can't seem to find any pumps under a $1000 that can pump at 6PGM.  I can use a weaker motor that can pump at 3GPM and divide the irrigation into two zones.

I found this:

https://www.altestore.com/store/solar-water-pumps/surface-solar-pumps/shurflo-surface-pumps/shurflo-12vdc-4gpm-bypass-surface-pump-p11020/

Is this the best type of pump? Can anyone guide me as to what type of panel I would need to power this? I will also probably need a controller. Should I run it direct or would a battery be beneficial. if so, what kind?

Thank you all for your help.

I had a small pump like that in a solar array with 12v  batteries. It had no torque. As in I could stop the flow by putting my thumb over the hose and stop the flow. If you have emitters in the drip line, could it clear out a clog?

Im not sure if there are good 12v units out there. I was able to get what i wanted from a 110v pump using an inverter.

EDIT.. looking at the specs,  its showing good psi. I may be totally wrong on this. Mine was same brand. Bought at tractor supply .

Sureflow pumps are great as long as you take into account the difference between max psi and max gpm... they intersect at some point below both numbers in a particular flow and pressure use. Some of the vane type pumps could work well also, little giant is a good one.

Here is a good controller for a pump under 16a @12v. You can find them cheaper, but these work well.

http://mwands.com/store/12-volt-dc-digital-programmable-timer.

Another option are the water timers that screw onto a hose bib and are a gearbox operated for lawn sprinklers. Good ones are reliable and operate for a season on AA size rechargable batteries. Rainbird etc. from hardware.

Unfortunately, it is a bit cheaper to use an inverter and a 1/3hp -1/2hp shallow well pump to supply water. Takes more power but less run time and pressure and flowrate are taken care of, you will not be able to stop it with a thumb and it will actually do 4gpm at pressure.

If you remove the drip emmiters and just use 1/4" tubes, then you can let gravity feed the water, no pump needed.

Fred Estrovich wrote:
I can't seem to find any pumps under a $1000 that can pump at 6PGM.  I can use a weaker motor that can pump at 3GPM and divide the irrigation into two zones.
Is this the best type of pump? Can anyone guide me as to what type of panel I would need to power this? I will also probably need a controller. Should I run it direct or would a battery be beneficial. if so, what kind?

I don't have any detailed advice, but I've thought about loads and system sizing many times.. If you're going to install a solar electric set up just to power this pump and you're only thinking you'll need the pump 2 hours a week at the higher power, then by all means go instead for less solar panels and a smaller pump to run for more time.

But I agree with Peter -- is a pump really needed for this system? Could your irrigation needs be served with just gravity feed?

I happen to have investigated this topic a bit the other day because I just got two 330 gallon water totes and was trying to figure out the best way to get the rain water to my garden. This is one of the videos I came across which may be of use to you:
https://www.youtube.com/watch?v=EiENdlXBezI

He starts talking about his pump and solar panel set-up for it right around the 3:00' mark.

Great discussion because I was planning the exact same things for my high tunnel. Hmm.

I've also heard that an above-ground tank will need to be painted to no let sunlight into the tank or lots of growth will occur that will likely clog emitters. I've decided to elevate my two IBC totes inside my barn and run he irrigation lines out. The total head from valve to growing beds is about 10 feet with a run of maybe 100 feet. I'm hopeful gravity and 1/4" tubes will do the trick and not a pressurized emitter system.

Peter VanDerWal wrote:If you remove the drip emmiters and just use 1/4" tubes, then you can let gravity feed the water, no pump needed.

We are getting ready to install a 1200 gallon rainwater system and are looking to distribute to a garden also. Although we would like to gravity feed water to the garden, water distribution can be a fickle aspect. Hoping to be able to accomplish gravity feed.

Those diaphragm pumps are pretty much the best at turning electricity into flow. Less power hungry then a jet pump but they wear out faster. If pumping from a tank you might even beat the flow rates listed since you have negative head. It won't run at the 15 amps listed probably closer to 10. So 120 watts of power per hour of operation plus losses due to battery efficiency and the peripheral timers you have to power. I would check out the ends on your irrigation system as well and see if I could not make it run gravity only. A lot of commercial gear assumes municipal water pressure so the end are a way to limit flow... not your problem.
Cheers,  David

Dan Grubbs wrote:Great discussion because I was planning the exact same things for my high tunnel. Hmm.

I've also heard that an above-ground tank will need to be painted to no let sunlight into the tank or lots of growth will occur that will likely clog emitters. I've decided to elevate my two IBC totes inside my barn and run he irrigation lines out. The total head from valve to growing beds is about 10 feet with a run of maybe 100 feet. I'm hopeful gravity and 1/4" tubes will do the trick and not a pressurized emitter system.

10 Feet of head will give you about 5 psi of pressure.  That is actually enough to run some types of drip emitters,  I think flag emitters would work at that pressure.  
1/4" open tubes would also work and are less likely to get plugged up by any dirt, etc. that is in the rain water.

Creating an automated system with electric valves could be a problem.  5 PSI isn't enough pressure to operate most of the common valves available.  However, you could do it with 'motorized ball valves'.  These don't require any water pressure to work, but they are typically a bit more expensive.