What size solar for well pump?

[russ]

NW Washington has pretty cold spells - the brass monkey would be several sizes too small - but they get lots of sun.

You only need to keep the tank at maybe 35

[Mike90250]

The solar collector would be BELOW the elevated tank, so the warm water can RISE (via thermosiphon) to the tank. use Poly tubing, that does not crack if frozen.

In my area, even at 25F, it takes a long time for 1500 gallons & 2" & 3" insulated pipe to freeze. Then spring comes.

I've had unprotected pipes crack, but no ice in the tanks yet.

[russ]

You get good sun there at least - a solar water heating panel (or two) on the structure might do the trick.

[Decidion]

I don't know if you mentioned it before but not everyone lives where it gets cold like your area. NE Washington does get a bit chilly for long periods.

Yeah, but is there some magic trick to keeping them from freezing? Having an elevated tank to provide the water pressure would be very convenient!

What about a small solar water heating system on the top of the elevated tank...something very simple, just enough to keep the water from freezing?

[russ]

How do you keep these from freezing solid as a rock during the winter?

I don't know if you mentioned it before but not everyone lives where it gets cold like your area. NE Washington does get a bit chilly for long periods.

[Decidion]

...You need to consider an elevated tank, that will provide gravity pressure all night long, till the sun is up again to run the pump.

How do you keep these from freezing solid as a rock during the winter?

[Mike90250]

....I have 63psi at tank, with a pressure tank it would run about 3 minutes,what size of array would I need.

Huge. You would need a 48V system, to have enough amps avaibable to feed the inverter DC, as the motor starts (surge reuirement.)

You need to consider an elevated tank, that will provide gravity pressure all night long, till the sun is up again to run the pump.

Or look into an 12 v RV pump that will take ground level water from your storage tank, and pressureise your system.


120V @ 24A starting, a 48V battery has to supply about 3000 watts to the inverter, @ 48V that's 62 amps

[Bigbirdd]

115 volt well pump

Hi . I have been reading tour threads about water well pumping. I am in the same predicament. I live off grid in north Idaho, My well is 240' deep my pump is at 140' I pump the water into a 275 gal water tank. I use a 6000 watt generator to run the pump. I would like to put a pressure tank in and run it on solar power. I build my own panels at 18v 63w 3.5a right now I have 10 panels witch runs my house. My well pump is 120v it draws 24a on start up for 1sec than 10a while running. I have 63psi at tank, with a pressure tank it would run about 3 minutes,what size of array would I need.

[Wy_White_Wolf]

Wow, at the US Dept of Energy avg of $8 - $10 per watt, that comes to about $18,000 just to run my well pump. I'm just shocked that it would cost that much.

If I bought a 1000 gallon propane tank + 800 gallons of propane to fill it = $6500 (roughly)
6Kw propane generator + installation = $3500 (roughly)

So about $10,000 total.

I would only need to run the pump about an hour a day (at 4 gallons of water per minute). The generator consumes .85 gal/hour at 50% load, so if I only used it for the well, I could run that well pump for over 20 years for a little more than half of what it would cost to run it on solar (assuming the batteries lasted 20 years, which I don' think they would).

After everything I have been finding out about solar power, at least for the area I am in (NE Washington state), I don't ever see a break even point (much less getting ahead). This is depressing.

That's why your better off replacing you pump with one that can be run solar direct. A solar slow pump that only pumps 1/2 to 2 gallons per minute but spends all day pumping into your storage. The tanks servive as your storage so no need for batteries. Cost would most likelybe in the $2k to $5k range

Hear are some examples

http://www.builditsolar.com/Projects/WaterPumping/waterpumping.htm

This is a really nice DIY system

http://www.otherpower.com/otherpower_waterpumping.html

[Decidion]

Lots of good input here I'll have to digest. I am thinking I am going to have to start out small and then just deal with only being able to fill our topside tanks on sunny days. This at least gets me started down the solar path, otherwise I might never get there.

Thanks for the feedback!

[Sunking]

Wow, at the US Dept of Energy avg of $8 - $10 per watt, that comes to about $18,000 just to run my well pump. I'm just shocked that it would cost that much.

Well you are comparing Apple to Oranges, and the info you read is old.

DOE is quoting a grid tied system (Apples), you want a Off-Grid Battery system (oranges). $8 - $10 watt sis 3 to 5 year old information for a grid tied system. Today $5 to $7/watt. Again you want a Battery Off-Grid System, not grid tied so forget all that jazz, it does not apply.

Battery systems are priced per Kwh not watts. For a grid tied system in your area will cost you roughly $4000/Kwh. So by your statement of a 1440 watt pump run 1 hour = 1.44 Kwh/day. That will cost you around $6,000, plus a generator and misc equipment.

Don't even try to figure break even point , because it is not possible with a battery system It will cost you at least 10 times more for electricity the rest of your life. Of that $6000 is $1600 battery that needs replace about every 5 years.

[Mike90250]

Propane is a less dense fuel than gasoline, I think it's almost 20% less.

Your startup surge that the inverter needs to supply, is going to be at least 5x the running power

My 1/2 hp pump, running, pulls 1,000w from the inverter (according to the inverters meter)) so that's at least a 5,000w starting surge.

I run 240VAC to my pump, 400', over #6 alum wire. Same as #8 copper.

240V AC 1/2 hp pump is the same watts as 120VAC, but half the amps.

Voltage drop calc in my .sig will help you a lot, figuring distance, amps and wire gauge.

Don't forget the wire splice to the underwater cable in the well, you have about 250' of likely #10 wire, unless you are lucky and they installed #8 down the well.

If you set the pump to only run while the sun is shining, a 600W array could keep batteries charged (making half the power you need) so you can downsize a lot. If you want to pump every day, rain or shine, and night, that's going to cost you.

[TnAndy]

You'd probably be better off to replace your existing pump with a Grundfos SQF series pump, and get the Grundfos CU-200 control box. Then you could run the pump on grid AC, sine wave AC locally produced, or directly off DC from solar arrays.

Since you are pumping into storage now, this is the idea pump to run directly off solar...skipping the conversion to AC, batteries and all that. You simply put a couple hundred watts ( depends on head, and flow you want ), and when the sun shines, the water flows.

They also make a generator interface to make it easy to connect a generator to the pump if solar isn't enough to run it ( like extended clouds ). If the generator runs out of fuel, the interface auto switches back to solar.

[Naptown]

I see where you are going with this, but it's not quite that bad with the propane genny either. Propane is only $2.20/gallon here and the maintenance interval on the genny is 500 hours. So the cost for the generator is probably closer to $20K. But that is still double what you came up with for solar costs.

I'm kind of thinking out loud here...but our house is 300' from the well. How far could I run a line that was pushing 110-120v before the loss was impractical or the size of the cable too expensive to justify?

300' is 300' whether it is the generator or PV. Voltage drop is a function of draw in amps and distance. To reduce voltage drop you would move the generator or the PV closer to the well or increase the wire size to accomodate.

[bluezman]

Maybe...

A Wood Gassifier? They ran trucks with them back in the early '40. Scrounge wood from the forest floor, It's still renewable and doesen't put any more CO2 into the atmosphere than if it were left to rot on it's own,...just does it faster.

Though, I would investagate why that honda won't do the job on propane first. There might be a cheap fix, or at least cheaper than all that money your talking about. Just some thoughts that popped into my head, bounced around a bit, so I had to let them out. Good luck.
Charlie