Solar-powered water supply

[rd_macgregor]

I'm working to fence in some new pasture for horses, but it is nowhere near a power supply or well. I'd like to pump water into a water tank (about 150gal) from a stream and am thinking of setting up a solar-charged battery system to run a marine bilge pump (I'd need less than 2m of head). Ideally, I'd alter the switching so it pumps when the water level is down, rather than up (as in a bilge), but I'm hoping for insights about the pitfalls of doing this water supply the way I'm envisioning it.
Any special advice, caveats, etc.??
Thanks.

 

[RNeumann]

Use a dc 12g pump.

Figure out a float switch that the horses won’t destroy.

Use a submersible pump as pulling a vacuum will take more power. And, in general, the type of pump that pulls a vacuum has relatively delicate impellers.

 

[CMV]

Subscribing for ideas. Have a similar need, but getting water from IBC tote to water large garden areas. Gravity with standard hose bib is such low flow that it takes forever....12V solar pump would be perfect since no electric utility service.

Right now I'm thinking that or a gasoline trash pump. Either has pros/cons.

To OP - one thought is does it need a switch? Could it be something smaller like a fountain pump on a timer to just run a few hrs per day? Regardless of demand, fresh water always being pumped in daily and excess can just overflow. Wouldn't need a lot of GPM or current draw that way - just slowly feed in ~5 GPH over a few hrs daily? A return line from top of trough back to stream even - pump in, excess goes back to stream, water "exchanged" for fresh daily, but pump not running long enough that solar can't recover.

 

[721]

If the stream has sufficient flow you could use a ram pump.

 

[TomIre]

I've seen setups with two float switches in the tank. The bottom one turns the pump on and the top float switch turns it off.

 

[rd_macgregor]

My other pastures have springs in them and, when I put in drain tiles to get rid of the springs, I installed "Y" fittings in the drain tiles to send some of the water into water tanks. The overflow then goes back into the tile drain.
This new field doesn't have any springs, though.
I thought of using a small fountain pump, but didn't think it would have enough head to fill the tank (I figure I need about 2 m of head). A marine bilge pump has huge capacity, but I would only need it to pump intermittently, so a solar trickle-charged battery should last a long time. I was thinking of putting a vertical pipe out the back (ie fence) side of the tank with a float in it and a covered/contained switch on top. A lag between on and off could be arranged any number of ways, eg, with slop or wobble in the connection between the float and the switch.

Even on a hot day, I doubt that I'd need to run more than 20 or 30 gallons into the tank, so I don't need a large flow capacity...if I knew for sure that a fountain pump had enough head, I'd try for continuous pumping whenever the sun shines, and let the overflow go back into the stream.

 

[CMV]

I use a small fountain pump for my home made lathe flood coolant system. Only lifting about 4', but I have the thing dialed all the way down and seems it could do much more. They can do a lot - only 1/2" tubing so not like other types of pumps trying to make the water flow thru much larger diameter. OTher stuff might work a lot better for you - was the lowest electrical drain thing I could think of to do it

 

[rd_macgregor]

I was thinking of something like this: Marine Electric Bilge Pump 12v. 5 gph for Boat, Caravan . Five Oceans (BC 3614), Bilge Pumps - Amazon Canada
Despite the link heading, the specs claim 500 gph...if this is correct, it would only have to run about 10 minutes per day (at full capacity) to supply all the water I'd need. Would something like this run automatically off a 12 solar array, whenever the array was producing full voltage, or would it have to be buffered through a battery, with an on-demand switch?

 

[CMV]

Would want a battery...and charge controller. A solar panel is going to put out all over the place depending on conditions - I would assume that would quickly destroy an electric motor continually giving it way too high and way too low voltage.

 

[oosik]

Neighbor has two very remote cattle watering stations. 2 foot by 3 foot solar panel - some kind of electronic charge controller - one 12 volt deep cycle battery - 12 volt pump - its only 12 to 15 feet to water. On/off float system had to be modified. It was an open two float system in the large watering tank. Cattle were knocking it around and it wouldn't activate the pump. Easy fix - put both floats and float mechanism in a metal box and bolted box to the side of the watering tank. Works like a champ. This summer will be the third year its been operating.

When he brings the cattle in for the winter - pulls the pump, controller, floats and battery. Leaves the solar panel out there - nothing out there to hurt it. He does tip the solar panel in the opposite direction so the "solar" side is protected from adverse weather and snow.