Best Inverter for deep well pump

[mvonw]

Looking for advice (preferably from someone who has actually done this) used an inverter to power my cabin. My primary draw is a 240 volt 1hp well pump @ 500 feet depth. I have been running it for years with a 6500 watt Honda generator, but even with that the generator pulls pretty hard when the pump kicks in. I would guess I need an inverter that would handle 4000 watt surges, at least.
Is one 48 volt 240 volt inverter better, or two 120 volt inverters ganged together better/more advantageous?

 

[kernel]

One inverter is usually less expensive and definitely less work and parts to install.

For a 1hp pump and other overlapping loads, you are about right on with 4000W.

A 120V inverter can also have a transformer added to output 240V to a circuit, line to line especially.

A typical 4000W house inverter will likely have more surge capacity than your 6kW generator and your pump will thank you, so will the neighbors/ other occupants if they are within earshot

 

[kernel]

I have done this many times...... our company builds offgrid outfits "from the well pump, up."

 

[offgriddle]

The only reason why I run my generator is to pump water and other heavy loads. I've toyed with the idea of replacing my perfectly fine, 240 VAC deep well pump with a dreamy, and expensive, grundfos soft start pump. I'm leaning towards going with a 24 vdc in, 240 VAC 5,000 watt invertor to run the existing pump and cabin when I've grown my solar farm enough to support it.

 

[Steve_S]

Looking for advice (preferably from someone who has actually done this) used an inverter to power my cabin. My primary draw is a 240 volt 1hp well pump @ 500 feet depth. I have been running it for years with a 6500 watt Honda generator, but even with that the generator pulls pretty hard when the pump kicks in. I would guess I need an inverter that would handle 4000 watt surges, at least.
Is one 48 volt 240 volt inverter better, or two 120 volt inverters ganged together better/more advantageous?

To keep the existing pump while providing the most per dollar, I would recommend a MINIMUM 24V system with a 4000W Inverter/Charger that outputs 240VAC Split Phase giving you two 120V legs as is standard in North America. I say MIN 24V because at 4Kw your at the end of the 24VDC threshold pretty much. Ideally, 48V/6000W/240VAC Split Phase would be the way to go and not have to stress any equipment at all. Also Pure Sine Wave LOW FREQUENCY is a virtual must because of the pump motor and tbh, it's the safest & best overall for all modern electronics.

Some Inverter/Chargers allow for Grid-AC Input, Genset Input and even Solar Input. Pricing of course is all over the place depending on what exactly you want and IF your wanting UL/ETL/CSA certified (seriously affects pricing but if you want insurance you might just have to)

You haven't mentioned using a battery pack nor if your installing solar as well. If your looking to just run the pump, that's one thing. If you think you may want to use this for more then a proper sit down with paper & pen + calculator will be needed to determine the loads, amperage & watts used. Then working out the battery sizing etc to handle that as well as figuring how much autonomy you want (if no sun or external power source is available)

 

[mvonw]

To keep the existing pump while providing the most per dollar, I would recommend a MINIMUM 24V system with a 4000W Inverter/Charger that outputs 240VAC Split Phase giving you two 120V legs as is standard in North America. I say MIN 24V because at 4Kw your at the end of the 24VDC threshold pretty much. Ideally, 48V/6000W/240VAC Split Phase would be the way to go and not have to stress any equipment at all. Also Pure Sine Wave LOW FREQUENCY is a virtual must because of the pump motor and tbh, it's the safest & best overall for all modern electronics.

Some Inverter/Chargers allow for Grid-AC Input, Genset Input and even Solar Input. Pricing of course is all over the place depending on what exactly you want and IF your wanting UL/ETL/CSA certified (seriously affects pricing but if you want insurance you might just have to)

You haven't mentioned using a battery pack nor if your installing solar as well. If your looking to just run the pump, that's one thing. If you think you may want to use this for more then a proper sit down with paper & pen + calculator will be needed to determine the loads, amperage & watts used. Then working out the battery sizing etc to handle that as well as figuring how much autonomy you want (if no sun or external power source is available)

Thank-you. Your recommendations pretty much align with my research. Yes, I am planning a 48 volt battery bank (size tbd, but the pump is my primary electrical draw along with minor lighting and a TV) . I think a 6000 watt inverter would handle it. I'm completely off grid, but I do want to interconnect with my generator and definitely a solar array. My general inclination is to over-spec it by a large margin to handle growth or estimation errors. I would love to find an independent consultant who wouldn't rip me off to help me design it. Unfortunately, the solar industry is full of people looking to rip you off and/or learn on your dime

 

[KauaiMolokai]

Hi MV, Well, you at the right place. There are a lot of very experienced, very smart people on here. And its FREE. ;-) The price you pay though is that you have to be very involved, and you have to be able to wade thru a lot of contradictory suggestions. But after a while you can pretty much figure out who thinks in a manner you respect and which conforms with your ideas. So, you won't get ripped off here. And you will learn a lot. And you don't have to trust one consultant who you'd have to pay and whose expertise you cannot know in a few days/weeks. In the end you will understand better than any consultant what you have designed and built. DIY rocks! My 0.2c worth is design with a large margin, no, larger than that, and don't try to save $25 here and there, but also don't buy "the best, super expensive" stuff. Because everything breaks. Be careful, but don't be paranoid ;-)

 

[mvonw]

Hi MV, Well, you at the right place. There are a lot of very experienced, very smart people on here. And its FREE. ;-) The price you pay though is that you have to be very involved, and you have to be able to wade thru a lot of contradictory suggestions. But after a while you can pretty much figure out who thinks in a manner you respect and which conforms with your ideas. So, you won't get ripped off here. And you will learn a lot. And you don't have to trust one consultant who you'd have to pay and whose expertise you cannot know in a few days/weeks. In the end you will understand better than any consultant what you have designed and built. DIY rocks! My 0.2c worth is design with a large margin, no, larger than that, and don't try to save $25 here and there, but also don't buy "the best, super expensive" stuff. Because everything breaks. Be careful, but don't be paranoid ;-)

Those are some remarkably reasonable and encouraging words of advice. But, yeah, wading through all the advice is the hard part. I'm not gullible, so I'm pretty immune to obvious silliness, but some internet armchair experts who've never actually done it are pretty darn convincing..

 

[Steve_S]

There are some of living & doing the offgrid life and have for years, some even decades and there are many lessons learned to be shared... There are also Armchair experts and a few youtube University graduates who wouldn't know which end of a screw driver to use... God help'em if they ever get a hammer hehehe...

First things First: DONT BUY ANYTHING !
- Make a PLAN because without a plan, you are planning for failure.
- Figure out for yourself what you are willing to invest into offgrid Freedom & Independence.
- Always keep in mind that you should have a 20% cash buffer above & beyond what you think you need to budget.
- Decide if you want to go all Tier-1 High Quality products. they cost more BUT you get what you pay for. Also down the road sometime, when the place you have get's sold, Name Brand Tier-1 products increase value, which 3rd Tier Value stuff does not. Tier One is Midnite Solar, Magnum, Victron (really nice) and so on. 3rd Tier is the cheapo value stuff that has no UL/ETL/CSA certifications either.
- Decide if you want everything to be "New" or is previously enjoyed acceptable ? There are phenomal deals on solar panels.
- As you are offgrid and intend to stay Free, you won't have to worry about special permits & grid installation inspections BONUS !
- ask questions, consider the answers & "opinions" with critical, logical rational thinking. Engage Common Sense and have a Cow Lick at hand.
- NO SUCH THING AS A STUPID QUESTION, Except for the one that is unasked !

Have a look at the various links in my signature, starting with "About my system", (needs to be updated, will be soon) and you may get a few ideas from there from practical application. Also do watch Will's Videos (great introduction to the basics) and look at the main website for more "docs" and reference info. NOTE: Will's main focus on Mobile, RV and such, residential is a tad more involved and he's just starting down that path.

BTW, One of our good members bought out a bankrupted solar installer and got all the inventory. @JeepHammer has the various pieces listed for sale to the membership at extremely reasonable prices, see links below. He is also a Treasure Trove of information as he has been an offgridder for decades and knows his stuff ! Threads related to JH's goodies and such.

I Now Have Two Semi Truck Loads Of Solar Equipment... Now What?

An entire semi truck load of panels that are nearly 6 feet tall, 250-350W An entire semi truck load of inverters, meters, combiner boxes, etc. So much I can't even inventory most of it. This most definitely is NOT the 'Hobby' stuff, all high end panels, high end, but older inverters, all...

diysolarforum.com

Whole House Inverters I've Checked So Far...

*IF* You want a big 'OFF GRID' (battery backup or powered) system, WATCH THIS VIDEO FOR AC COUPLING instead of all DC wiring, and save money on big systems... ===================================================== As per Will's approval, I'm posting here. I'm going to share with forum users...

diysolarforum.com

Hope that helps.
Steve

 

[svetz]

I always suggest replacing it with a DC pump (esp. if the current pump is elderly) so you can skip the inverter all together.

 

[mvonw]

A dual AC/DC pump might be a good idea. I don't know much about them and the well driller in my area is pretty stone age. Might be worth looking into. From my limited research, it looks like the DC pumps need 120 volt to run properly, how would that work with with 48volt battery?

 

[boondox]

That is pretty deep for most DC well pumps. What is the distance from the top of the water in the well to the surface? I'd stick with the pump you down the hole. There are already some great inverter/power suggestions above to run it.

 

[Steve_S]

Well, if your pondering replacing the pump, then dive right in, get a Grundfos SoftStart SQ series and never worry about it again. They have 120V & 240V with various capacities. They are NOT cheap but they are the cat's meow.

Submersible Well Pumps

Grundfos submersible well pumps are available in a wide range of sizes and materials to fit your application needs.

ca.grundfos.com

 

[MichaelK]

I've been running my well pump solely off of solar for three years now, and I'm very pleased with the results. I have a 1hp Grunfos 240VAC pump, that's similar to yours. I would disagree with the 24V suggestions given above. Using a clamp meter on the control box, I found the my wellpump draws about 10amps while running, but 37-38amps right at startup. This was measured with a Fluke meter with the ability to measure "inrush current". That's 9000+ watts at startup. I install a 48V Schneider XW+6848 to power my pump, and it has performed flawlessly the last three years. My panels are on rotating mounts, so I can face them eastward in the morning, then turn west in the afternoon. With my panels, I can keep the pump running with no battery depletion from about 8:30am till 4:30pm. If sticking with 24V is important, one alternative that might work is a Dual-Conext SW4024s wired in parallel. It's also a 120/240VAC inverter, but when two are linked in parallel, they will match phases and double output.

 

[Steve_S]

I have a Grundfos SQ-5, 120V Soft-Start.
I use a Samlex EVO 4024 (24V/4000W) Inverter Charger.
It's 250' deep and has to push to 50 Gal Pressure Tank in Pumphouse & then 75' to house.
PSI is set to 45.
At start, it's pulls 550W and stages up to 1100W when reaching set pressure. (never measure the amps with a clamp, W displayed on EVO)
Never ever notice pressure drop, never been a problem. This is the Winning BONUS for Solar & using an SQ Soft-Start !
* not all Grundfos pumps are soft-start though.

As previously stated though, with 24VDC the top side is pretty much the 4000-5000W after that better go with 48VDC if you need more Inverter wattage to be delivered.

 

[MountainMatt]

The only reason why I run my generator is to pump water and other heavy loads. I've toyed with the idea of replacing my perfectly fine, 240 VAC deep well pump with a dreamy, and expensive, grundfos soft start pump. I'm leaning towards going with a 24 vdc in, 240 VAC 5,000 watt invertor to run the existing pump and cabin when I've grown my solar farm enough to support it.

I've got a Grundfos 6 SQF 3 540ft deep running off 4S 275W 36v panels on the shed roof and and IO 101 switch with generator backup, which is just a Honda 2200. Works great.

 

[offgriddle]

I've got a Grundfos 6 SQF 3 540ft deep running off 4S 275W 36v panels on the shed roof and and IO 101 switch with generator backup, which is just a Honda 2200. Works great.

Thank you MM for sharing your water pump set up, very inspiring & duly noted. OG

 

[mvonw]

I've got a Grundfos 6 SQF 3 540ft deep running off 4S 275W 36v panels on the shed roof and and IO 101 switch with generator backup, which is just a Honda 2200. Works great.

Thank you for sharing that! I was looking at this pump. It looks like it will do 2 gpm at the depth, is that consistent with what you are seeing? I have a eu2200 also, I’m superprised that pump doesn’t surge beyond that, my current pump definitely needs 6500watts..

 

[MountainMatt]

Thank you for sharing that! I was looking at this pump. It looks like it will do 2 gpm at the depth, is that consistent with what you are seeing? I have a eu2200 also, I’m superprised that pump doesn’t surge beyond that, my current pump definitely needs 6500watts..

I am getting about 8 gallons a minute on the generator and 5gl easy during summer midday sun. It's a darn good pump!

 

[mvonw]

I am getting about 8 gallons a minute on the generator and 5gl easy during summer midday sun. It's a darn good pump!

Whoa, that's awesome. Too bad my well doesn't recharge that fast! I'm gonna git me one of them Grundfos pumps!!