What makes more sense to power an irrigation pump - solar or running a line?

[rsilvers]

I was asked about running a well pump for lawn watering off solar.

It would cost $2250 to run a power line to the house. I suggested he should do that, as solar could cost maybe 3-4x that.

He is not sure what size his well pump is, but if it is 1.5HP, that is 9.6 amps at 230v. Pump would run for 4 hours a day.

Location is near Boston. Based on what kind of panels and batteries this would need, what is a rough estimate of how much such a system would cost?

[SunEagle]

I feel it is pretty much cheaper to run the grid to a load then to use a solar/battery system. The bigger the hp of the pump the easier it would be to justify running the grid because the solar/battery system would just grow in size and cost much faster then a grid "extension" cord.

As for the specific issue with a 1.5hp motor running 4 hours a day. That calculates to ~ 2200 VA (9.6a x 230v = 2208va). But if you figure a .70 PF the wattage is lower at around 1600 watts.

So for 4 hours he would be using 6400wh or 6.4kWh a day. We have seen some figures between $2000 - $3000/kWh for a solar/battery off grid system so it could cost anywhere between $12k to $20k for a solar/ battery system.

That is a lot more expensive then the $2250 to run power from the house.

[azdave]

No question that connecting to the grid is the best choice, even if it were double or triple the cost to run grid power. With off-grid solar you will always pay much more for maintenance, repair and battery replacement. No need to do the solar math further when you have cheap grid access.

[Sunking]

I was asked about running a well pump for lawn watering off solar.

You should have laughed and walked away. No contest go $olar

He is not sure what size his well pump is, but if it is 1.5HP, that is 9.6 amps at 230v. Pump would run for 4 hours a day.

Location is near Boston. Based on what kind of panels and batteries this would need, what is a rough estimate of how much such a system would cost?

Panel Wattage = 4000 wattts. = Roughly $5000 to $8000
80 Amp MPPT Charge Controllers = $600
48 volt @ 900 AH = $9000 = 2500 pound = replace every 4 to 6 years ar higher cost
Pad and building to Hold batteries and equipment = $4000
3000 watt Pure Sine Wave Inverter = $1500
Misc Materials and hardware = $2000
Labor and Permits = Who gives a crap what it cost, it's Solar.

Total estimate without labor and permits = $22,000

Go Solar as it is a much better deal than that mean ole power company charging you $2 a month.

[rsilvers]

I guessed $8000 and told him that, but said I would ask for him and send him a link to the answers.

[SunEagle]

I guessed $8000 and told him that, but said I would ask for him and send him a link to the answers.

He might be able to find used or cheap batteries or very low costing panels but more than likely you get what you pay for and the system will stop working in a year or so.

Even going cheap on the solar / battery hardware will still cost him more than that $8k but then again he might not believe you until he goes out and does the purchase and install and then comes back to ask why the system isn't working. That has happened more time then I can count because a lot of people with zero solar experience do not believe what we tell them.

Heck I was one that went ahead to build a small portable system. I spent more than $2500 for a system that will safely get me about 600watt hours a day. If I had listened I could have built a better system (700wh) for $1500. Live and learn but boy the loss of the money can hurt someone.

[solarix]

A reasonable solar solution involves doing the water pumping differently from a grid AC method. A solar, low-flow pump feeding a low flow irrigation system would be practical if no batteries are involved. There are lawn irrigation systems that are under-turf drip irrigated that could be fed by a small DC pump running directly (well - needs a controller) off a couple solar panels.

[SunEagle]

A reasonable solar solution involves doing the water pumping differently from a grid AC method. A solar, low-flow pump feeding a low flow irrigation system would be practical if no batteries are involved. There are lawn irrigation systems that are under-turf drip irrigated that could be fed by a small DC pump running directly (well - needs a controller) off a couple solar panels.

True. You can find a DC pump that runs directly from a solar panel through it's controller and use it to fill a storage tank. But the reference was for a 1.5hp 230v AC motor.

[Sunking]

Windmill comes to mind. Farmers have used them for centuries.

[SunEagle]

Windmill comes to mind. Farmers have used them for centuries.

Burros have also been used to pump water but the cost to feed them is very high.

[Sunking]

Burros have also been used to pump water but the cost to feed them is very high.

Its India. You can get a Laborer 16 hours a day for sandwich. Heck in India you don't even need meat in the bun, just some weeds, sour stuff, and a hot pepper.

Seriously hand cranks are used widely. Go to any large construction site using heavy equipment. You will see one of two things. Either a Pickup and a guy with a Hand Crank pumping fuel. or a elevated tanks. Here in Panama you see a lot of elevated tanks at gas stations. All gravity fed. The delivery trucks have engine PTO's to pump the fuel out of the truck to an elevated tank. All this guys needs is an elevated tank, engine pump, and use less than a gallon of the fuel to pump it up to a elevated tank. No engine pump, no problem a Hand Crank pump and a sandwich.