Solar pump recommendations

[Bigblockyeti]

I need a 12V pump to get water from the creek behind me into a pair of 330 gallon totes that will be used for gravity irrigation. It doesn't need to have tremendous flow, even 1/2 gallon per minute would be plenty since it'll be running anytime it's sunny out. The head is my concern, it will be just under 40' and a total length of ~500' which prioritizes pressure over flow. A 12V well pump would have the pressure but more flow than I need demanding current beyond what I want to set the panel & battery up for. Any suggestions that would handle slightly dirty water (think sock filter) while providing good pressure and low flow? I've looked into RV fresh water pumps but most likely wouldn't last long outside or pumping creek water. I've also considered a ram pump but the creek has little fall over 600' and it's narrow and curvy making the installation of a drive pipe problematic. Something submersible would be ideal but not an absolute requirement.

 

[Jackfre]

I was just looking at one at Tractor Supply the other day. Check theirs out.

 

[DetachedGarage]

Sounds like an interesting project for my engineering mind. The first thing that came to my mind would be a hydronic pump similar to what you would use in a radiant slab.

Pumps at Menards

You would have to rig up the solar/battery with an inverter, but it could be an option... The other would be a spare geothermal pump that is used on a open loop system. You could probably adapt one of those to your needs, and those are often used to pulling out of ponds/lakes.

 

[ddawg16]

40' of head is close to 18 PSI of pressure.

The length of pipe is not a real issue unless you want to go fast.

Sounds like you have already done some of the math saying you want about 1/2 gal a min.

660 Gallons in an 8 hour period (I'm assuming you're running this off solar)

A typical 8 hour day is 960 min....so you really need to pump .6 Gal a min to get done in a hour day.

I would not go below 1/2" pipe/tubing. That should keep the line losses down....and let you run a smaller pump. If you get one rated for 1 gal/min at 50 PSI, I would think you would be fine. I would add a valve on the output so you can throttle the rate back as needed.

I would also suggest a check valve to prevent water from turning the pump backwards when you turn it off. It will also help with startup.

 

[Bigblockyeti]

I'll certainly use a check valve to keep the water from back flowing, or a foot valve if I end up using a non-submersible pump. The tubing diameter will likely be between 1/2" & 3/4" whatever I can get costing the least. I'll be feeding the tanks at the top to remove the chance of a plumbing failure draining all water from them. The tentative plan is to use drip irrigation gravity feed from the tanks, timing controls haven't been completely determined yet, but it'll be something that will also run on 12V. The pump specs are just rough and close to what an RV (only ~$30) should cost. I've also seen where the less the pump costs, the harder it is to get flow/pressure specs. Depending on how much excess capacity the pump ends up with beyond what I need, I might put a float switch in one of the totes so it doesn't just make a mud hole around it. I could also incorporate a flow sensor on the output drip line with a tank level sensor and throttle the pump with a PVM controller. I could get complicated enough quickly to make it into a very expensive system which at this point isn't necessary.

 

[kbs2244]

This guy talks you through the math and reasoning behind it.

https://survivalblog.com/diy-solar-well-pump-pja/

 

[ddawg16]

This guy talks you through the math and reasoning behind it.

https://survivalblog.com/diy-solar-well-pump-pja/

Nice write-up....and sanity check.

I'll certainly use a check valve to keep the water from back flowing, or a foot valve if I end up using a non-submersible pump. The tubing diameter will likely be between 1/2" & 3/4" whatever I can get costing the least. I'll be feeding the tanks at the top to remove the chance of a plumbing failure draining all water from them. The tentative plan is to use drip irrigation gravity feed from the tanks, timing controls haven't been completely determined yet, but it'll be something that will also run on 12V. The pump specs are just rough and close to what an RV (only ~$30) should cost. I've also seen where the less the pump costs, the harder it is to get flow/pressure specs. Depending on how much excess capacity the pump ends up with beyond what I need, I might put a float switch in one of the totes so it doesn't just make a mud hole around it. I could also incorporate a flow sensor on the output drip line with a tank level sensor and throttle the pump with a PVM controller. I could get complicated enough quickly to make it into a very expensive system which at this point isn't necessary.

If it was me....

I'd plumb the two tanks in parallel at the bottom....that way they both keep the same level at all times....

The float is a good idea....
For simplicity, you could use a mechanical switch at the pump source to shut off the pump when the pressure goes above, say 50 PSI....like when the float shuts off the output? You could also add a timer timer so it can only run during certain times.

One issue you want to avoid is a cut line making a bigger mud hole.

Down side of a pressure switch, if you have a leak anywhere, it could cause undesirable results.

 

[Bigblockyeti]

That is a good write up and has some of the hurdles I'm looking at too. Keeping the city water turned on would be $26/mo. if I used zero water and that would be another perpetual bill, likely worth it if we lived there, but we don't. Another is the $1800 tap fee as we don't have one yet and I'm not convinced it would be a good ROI if we decided to sell instead of building. The repackaged diaphragm pump makes sense to me as centrifugal pumps just don't have the pressure unless spinning at a higher and constant speed. Taking a ~$50 pump and adding $170 to make it submersible probably is something I don't need but some kind of enclosure would be needed for it to sit in the weather next to the creek. Whatever pump I end up going with, I want to make sure they offer enough support to get me all required filtration information and stock replacement parts if/when needed.

 

[Jarwop]

Thanks for mentioning the ram pump. I googled it and have spent a couple hours watching youtube videos about how they work. Very interesting!

 

[JAYoung]

Hydraulic ram pumps are pretty cool, but they can be annoyingly noisy unless you insulate the sound they make.
Also, once saw an Amishman who built a waterwheel with an offset crank, hooked to a 100-yard cable that made the handle of his old-style hand pump go up and down. That was pretty noisy too.

 

[theoldwizard1]

Thanks for mentioning the ram pump. I googled it and have spent a couple hours watching youtube videos about how they work. Very interesting!

A ram pump works by recovering energy from falling water (so the outlet must be below the inlet) and using that energy to push SOME water back up hill.

Lots of video on ram pumps, some are pretty large. Frequently, the water is piped from more than 100 yards upstream to get adequate pressure to run the ram pump.

Another YouTube channel to check out is Engineer775.

 

[zeke67]

I haven't purchased anything yet, but I need to move lake water with about 40' of head somewhere between 300 and 400 feet uphill. Remote application, no grid. As pointed out already, it's the height, not the distance. There are several brands of 12V solar pumps that are for direct connection to one or more PV panels. You can add linear current boosters to them to improve performance and accommodate options like float switches. Others will require batter storage. Some are submersible, others are surface pump styles. Most of them are positive displacement and depending on the manufacturer either require filtered clean water to prevent pump damage or have components that are regular maintenance items. Prices range from a few hundred for a solar pump. Which means for a simple system with one PV panel you can be in the game for around $500 (assuming it moves the amount of water you need and meets your head requirements). Other types start at a few thousand. I've looked at brands like Dankoff, Grundfoss and Shureflo seriously and there are others as well.

 

[Bretny]

Solar pumps sound cool and all but they are expensive and very limited.

If all you need to do is fill a few IBC totes every now and then maby a generator and a real well pump is in order. You also have the benifit of having 120v if needed. All these things can be bought used becids the piping. I see well pumps for $50 quite often. Never saw a used solar pump...ever.

 

[Bigblockyeti]

Well I bought this: https://www.amazon.com/gp/product/B00WYMC492/?tag=atomicindus08-20

It was cheap enough and running off a regulated 12V power supply it pulls less than 1 amp running no head pressure. Next is a 50W or 100W solar panel that will be connected directly with a low voltage cutoff module ~100' of 12ga. wire and a 600' roll of 1/2" drip irrigation tubing to fill the totes. I'll use a float valve, much like a toilet cut-off to keep it from just constantly overfilling by triggering the built in pressure switch to turn the motor off. I've assembled a rudimentary filter with a pre-filter that will be changed monthly. I made a dirty water slurry in my garage sink to make sure less than perfect water wouldn't be an issue and it's working well under less than ideal circumstances. Max current was right at 2.7amps just before the pressure cutoff. Given my head pressure under normal filling, it shouldn't ever exceed 2 amps except as the fill valve closes. The pump and cutoff module will both be enclosed in a waterproof project box to keep them out of the elements.

Total investment minus the totes will be under $220 all said and done. Even if an $18 pump has to be replaced every 6 months, it will be far less expensive than a monthly municipal water bill.

 

[theoldwizard1]

Buy a rebuild kit. Diaphragms don't last forever.

 

[Aerospace Eng]

It sounds like you have found a solution, but if you have decent flow in the creek, you can always build a completely mechanical solution (paddlewheel powering a positive displacement pump). You just need a large enough diameter to produce the torque you need to run the pump.

It will work 24/7.

 

[Bigblockyeti]

Not much flow in the creek, just a trickle after a couple weeks with no rain. I'll likely dig out a little well for the filter to sit under a rock in a deeper spot. It can swell pretty big after days of constant heavy rain but I'm planning on tying everything off to a tree or two so it won't be swept away if/when that happens.

 

[Aerospace Eng]

An alternative to a paddlewheel driving a pump is just a coil on the paddlewheel. I didn't think these would have the head you require, but they apparently do.....

https://lurkertech.com/water/pump/tailer/

Didn't see your reply as to flow.....

Ignore all after "click."

 

[zeke67]

Check the 50 or 100 Watt panel you are going to use for the volts at maximum output. If it's much above 12V, which it may very well be at 100W, you will need a charge controller and battery or boost controller. As mentioned, solar pumps are expensive. But...they allow direct connection to your array.

 

[theoldwizard1]

Expensive, but it allows you to run a 120VAC pump directly from a solar panel.

PicoCell 2000

 

[Bigblockyeti]

Check the 50 or 100 Watt panel you are going to use for the volts at maximum output. If it's much above 12V, which it may very well be at 100W, you will need a charge controller and battery or boost controller. As mentioned, solar pumps are expensive. But...they allow direct connection to your array.

I'm going with a 100W panel to ensure adequate capacity, the two pumps I have pull 2.8A & 3.1A respectively at cutoff pressure. The panel puts out a maximum of 100W at just under 18V, I'll be regulating it down to 12V and under less than idea sun I should be just a little over what I need to run whichever pump I install. I don't need a battery based on what I'm trying to accomplish, it's just another unnecessary expense. I bought a small splash resistant tool box for under $4 to protect the pump and voltage regulator from the weather. Still looking like everything should fall under my $220 targeted project budget.

 

[Bigblockyeti]

I'm well aware of my limitations, all I'm trying to do is get a couple hundred gallons per day of lightly filtered creek water into storage which will likely be two 330 gallon IBC totes ultimately used for drip irrigation. I'm well aware the pump won't last long, that's budgeted as an on going operation. The solar panel, wiring and tubing I expect to last quite a while. I'm a long time subscriber to the KISS design principle and it's not going to get any simpler and still function deviating from the design I've described.