Power setup for 220 volt deep well pump

hhbartlett · April 23, 2012, 09:33:25 AM

On my land I already have a well in place (house burnt down previously). It's a fairly new well, 7 years old, and apparently good quality and quantity of water. In fact, the well gear is still in it, including the submersible pump.

I have a problem, however. First, I'm not sure if & when we can get power hooked up from the grid. And in fact, we're not sure we want it. I'd like to at least have the option of being off grid, if not now, then later. The problem is, the well is 300 feet deep. Assuming they used a properly sized pump when installing it, which I'm sure they did, that means it's at least a 1hp. I know it's 220v (4 wire). That means it probably pulls 7 or 8 amps @ 220V. Another problem I have is this is a best guess; I have no documentation or information on it. I do know it's a 300 foot deep well, that's it.

So if not on grid power, what kind of inverter can you get to run something like that? Something less than several thousand dollars, I mean. The vast majority of inverters I've seen are 110 volt only. Or do you go for a 3000 watt inverter, and then add some kind of transformer for the 220V load?

zion-diy · April 23, 2012, 09:54:21 AM

Being 4 wire and 300 ft, I'm guessing the pump is 1 1/2 hp. I don't know of any inverter or battery bank that would run that. (others may chime in on that). on my 1 1/2 pump, I wired a 5500 watt generator for back up power. It barely got the job done. (grunted a bit on start). future calls for 6500 watt gen.

April 23, 2012, 10:00:19 AM

Quote from: zion-diy on April 23, 2012, 09:54:21 AM
Being 4 wire and 300 ft, I'm guessing the pump is 1 1/2 hp. I don't know of any inverter or battery bank that would run that. (others may chime in on that). on my 1 1/2 pump, I wired a 5500 watt generator for back up power. It barely got the job done. (grunted a bit on start). future calls for 6500 watt gen.

Ya, that was my worry. I'm thinking that if it's going to be off-grid, then I'd need a holding tank "up top" and occasionally run a generator to fill it from the well. Sucks. The thing is, there's another well on the property, the old hand dug well and I can see water maybe 15 to 20 feet down. However, I don't know how well that would work with regular use, or how good the water is (looks clear but that doesn't mean anything). I'm also told there as a spring somewhere up in the woods in back they used to use. Maybe I'd have to find that, although I wouldn't have the first clue about how.

davidj · April 23, 2012, 10:03:09 AM

Also remember it's not just the inverter - you need decent batteries to pull that much power for any amount of time too.

MountainDon · April 23, 2012, 02:00:46 PM

If you are going to be off grid it may be best to replace the present pump with something like a Grudfoss that is designed for off grid / solar PV.

Also cheap inverters will not cut it; The Outback, Magnum and bigger Xantrex can all drive a pump. Most of those will stack two inverters to get the 220/240 VAC, though there are some models that produce 120/240 from a single unit. $$$$

April 23, 2012, 02:45:06 PM

Probably the least expensive solution might be to buy a larger generator and run it to a holding tank or cistern. My 6500 watt gen only cost a few hundred $$ from HF and has a 240 receptacle on it.

Watch with shallow wells and springs. They can easily pick up whatever pollution there may have been in the surrounding area that you don't know if it exists. Also in the old days people used to have cesspools and didn't realize they could leak into a shallow well. You can have the shallow well tested for really cheap in most places (like $100). As long as there is no pollution or fecal bacteria, you can treat it like a rainwater catchment cistern. With a .1 micron filter and a UV sterilizer, it should be safe to drink on a regular basis.

hhbartlett · April 23, 2012, 02:51:59 PM

Quote from: Squirl on April 23, 2012, 02:45:06 PM
Probably the least expensive solution might be to buy a larger generator and run it to a holding tank or cistern. My 6500 watt gen only cost a few hundred $$ from HF and has a 240 receptacle on it.

Watch with shallow wells and springs. They can easily pick up whatever pollution there may have been in the surrounding area that you don't know if it exists. Also in the old days people used to have cesspools and didn't realize they could leak into a shallow well. You can have the shallow well tested for really cheap in most places (like $100). As long as there is no pollution or fecal bacteria, you can treat it like a rainwater catchment cistern. With a .1 micron filter and a UV sterilizer, it should be safe to drink on a regular basis.

I'm thinking that's probably going to be the solution (generator to holding tank). If I go that route, it will be a buried cistern and I'll supplement it with rain water too.

Redoverfarm · April 23, 2012, 08:05:48 PM

I went for the Grundfos 240 volt slow start pump and the Magnum inverter just for the mere fact that you only need one inverter to invert into 240 volts. Yes they are a little pricey (Each) but when you need it and need it for long term it is a trade off verse Grid Power.

LuvHartwell · October 19, 2013, 07:11:58 AM

I'm in a similar situation. I've been researching what I need to put together to build a solar backup system for my small house http://countryplans.com/smf/index.php?topic=5501.msg70345#msg70345 . There was an existing drill well on my property with 220v submersible pump that was only a few years old.

The guys at Missouri Wind and Solar turned me on to a newer inverter/charger made by AIMS. It's 6000 Watt Low Frequency Solar Inverter Charger(Pure Sine Wave) - 24 volt- Split Phase.

The built-in split phase allow you to do 220 power without having to buy a second inverter or a transformer. It has a 6000 Watt continuous output with 18,000 Watt serge capability for 20 seconds. That will run everything in my small house except for the range/oven which I wouldn't want to run off a battery bank anyway.

It's also a built in MPPT charge controller and has automatic transfer switch capabilities. It appears to do everything I would need and then some.

Here's a link to the product page http://www.aimscorp.net/6000-Watt-Pure-Sine-Low-Frequency-Solar-Inverter-Charger-24-Volt.html

It sells for around $1,999 which includes shipping. I know that sounds expensive. In my situation it was actually cheaper to buy this unit then to purchase a charge controller, Inverter, and transformer separately.

I purchased my solar panels and the AIMS Inverter/charger earlier this week on 10/16. Nothings arrived yet.

I'm planning to buy my batteries from a local electrical supply company that can get me Trojan L16RE's at a good price.

I'll start posting more about this project on my Owner Project page as things progress.

Best,

Tony

October 19, 2013, 11:05:05 AM

Here's a question along this same subject line.

What's the minimum size generator (surge watts/continuous watts) that I would need
to start and run a 1/2 hp, 240 volt, 4 amp submersible pump ?

I'm looking at the Harbor Freight 4000/3200 watt model
and was wondering if it would do the job.

Thanks,
Arky

upa · October 21, 2013, 10:32:47 AM

Quote from: Arky217 on October 19, 2013, 11:05:05 AM
Here's a question along this same subject line.

What's the minimum size generator (surge watts/continuous watts) that I would need
to start and run a 1/2 hp, 240 volt, 4 amp submersible pump ?

I'm looking at the Harbor Freight 4000/3200 watt model
and was wondering if it would do the job.

Thanks,
Arky

Its probably ok but I think it might be marginally suitable, the 4 amp rating @240v is a constant draw rating and the generator could easily handle that constant load. What you really need is the LRA rating or what amperage it takes at start up which can be easily 4x the run rating. It just may not have enough power to start the pump or it may, hard to tell with available info.

Patrick · October 21, 2013, 12:16:19 PM

Don't forget when you under power motors and they cant start properly they just sit and smoke, Burned up an air compressor using a generator that was not strong enough. I think those well pumps can get expensive.

Redoverfarm · October 21, 2013, 05:18:23 PM

Quote from: Redoverfarm on April 23, 2012, 08:05:48 PM
I went for the Grundfos 240 volt slow start pump and the Magnum inverter just for the mere fact that you only need one inverter to invert into 240 volts. Yes they are a little pricey (Each) but when you need it and need it for long term it is a trade off verse Grid Power.

Another tid-bit concerning your well pump. Mine draws 9.8 amps which is a slow start and no surge. But even then when you convert DC power to AC that amounts to almost 31 amps of DC to reach that 9.8 amps.