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240v well pump -> offgrid

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FightThePower

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Sep 2, 2021
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Guys I have a 2HP 240v well pump that has surge current of 23A and run current of 13A. I am looking for an all in one inverter to run it. Or even better a batteryless inveter to run it. Any ideas what type of inverter will do the job? Anyone have experience running 2HP well pumps with an inverter? The well pump is on its own circuit and will not have other house loads on the inverter.

Thank you!
 
Where did the surge current value of 23A come from? The motor label or testing. Seems low for a 2hp induction motor. Usually LRA is 4 to 6 times Run Load Amps. Does it have a soft starter or VFD built in.
1) Inductive motor loads are the most demanding item you can connect to an Inverter. Batteryless is probably not going to work, you really need the storage capacity of a battery to handle the surge.
2) For your application a Low Frequency inverter with a big transformer is recommended. Something in the 5kW size range.
3) Verify the surge current of your motor and consider adding soft starter unless it already has one or a VFD built in.
 
That's pretty low of a surge current. Most low freq inverters will start it. Mine is 3/4 hp but 61a surge and the lvx6048 started it just fine.
 
I feel like that number is really low too. I may have to go and check that again. I got a clamp meter and checked it but was surprised at the low start current.
 
FightThePower said:
I feel like that number is really low too. I may have to go and check that again. I got a clamp meter and checked it but was surprised at the low start current.
Click to expand...
I know my meters all have different ways they need to be set to measure things so take a minute to study those settings. I have at least three clamp on meters. Also I am often surprised by what a new set of batteries does to make my meter behave regardless if the meter is giving a low battery warning or not.
 
The meter does do inrush "max hold". I have another 2HP above ground booster pump that reads 44 amps surge so I think the clamp is working. But I will try it again. The well pump has a start cap and run cap in a box above ground and it may be one of the soft start grandfos pumps. I need to try and dig up the model number on the pump.
 
FightThePower said:
The meter does do inrush "max hold". I have another 2HP above ground booster pump that reads 44 amps surge so I think the clamp is working. But I will try it again. The well pump has a start cap and run cap in a box above ground and it may be one of the soft start grandfos pumps. I need to try and dig up the model number on the pump.
Click to expand...
if it has a soft start than that would explain the low draw
 
Im not sure it has a soft start, it probably does not but I will try and dig up the model number and see what I have. Im pretty sure its a grandfos pump. Maybe i got lucky and they put in a SQ model when we did it 8 years ago.

I will report back on that and twke more readings. But I am pretty sure its only pulling 22-23amps at startup. I measure it a few times today.

I have a champion dual fuel gen that makes around 6000 running and 7000 starting watts on propane. And it will fire up the well pump and the booster pump one after the other and run both at the same time.

Im just trying to get a backup for the backup for this well in case grid is down and Im out of propane to run a gen. I already have 5000w of solar panels grid tied on the well pump main panel. I just want to throw an offgrid capable inverter and battery in ther in case things go bad. Im watering several acres of fruit trees with the well and need it to be working no matter what happens. If its 100F out and the power is off for several days at a time, the trees get damaged. It was off for 2 weeks one time we had a wildfire.
 
Hello, fight thepower
I have an irrigation system consisting of three pumps. Two pressure pumps 1.5 and one horsepower and a deep well at 1.5 hp Growatt SPF 6000T with 3x EG4 batteries and 5kw solar will run any combination of two pumps but not the third. The system pumps about 1500 gallons of water every day for 9 acres of landscaping. Has been in service for 4 months now with no issues (other than overload on third pump due to well pump timer running at the wrong time)
Happy with performance. not quite the two HP your looking at but all three pumps are across the line starting, no soft start. I have not checked starting current.

Bruce
 
FightThePower said:
The pump is a goulds 7gs20412cl. No soft start.
Click to expand...
I am running the 10gs15, pump starts at approximately 13 gpm and 2200 watts and tapering to rated flow of 10. Gpm at about 1850 watts. Pump goes to gravity storage so no pressure head, I would guess about 10kw starting power. 6000t has no problem with that.
 
Last edited:
I would look at running a 3 phase pump off an inverter - gives you speed control (pressure regulation) & none of the single phase inrush nightmares.
 
brucenolan said:
I am running the 10gs15, pump starts at approximately 13 gpm and 2200 watts and tapering to rated flow of 10. Gpm at about 1850 watts. Pump goes to gravity storage so no pressure head, I would guess about 10kw starting power. 6000t has no problem with that.
Click to expand...
My system also goes to a big holding tank and has only the head pressure working against it. Do you know the depth to water in your well?

I was studying the performance chart for these pumps and it looks like I could be getting a lot more water out of a pumpmwith less stages. Or a lot less power usage and same water flow from a smaller motor on a pump with less stages.
Quattrohead said:
Have a look at the LVX6048 does not need a battery, or the Growatt SPF 6000T that does need a battery.
Both are 6kW big heavy transformer output units.
Click to expand...
Thanks, I will check those out. I probably want something thats UL listed and outdoor rated. Theres no building near the well. Im considering building some kind of pump shack.
 
FightThePower said:
My system also goes to a big holding tank and has only the head pressure working against it. Do you know the depth to water in your well?

I was studying the performance chart for these pumps and it looks like I could be getting a lot more water out of a pumpmwith less stages. Or a lot less power usage and same water flow from a smaller motor on a pump with less stages.

Thanks, I will check those out. I probably want something thats UL listed and outdoor rated. Theres no building near the well. Im considering building some kind of pump shack.
Click to expand...
Static water level is 140' pump is at 480' about 20' additional head to top of 3000 gal tank
 
I just did what what you are asking about. I took my 1.5hp deep well off grid with grid backup. I have it set to prefer the batteries, and some may laugh at the 12v batteries running a 1.5hp pump, but I have no issues in 4 months. Pump only runs for about 70 seconds at a time to fill with pressure tank from 35-55psig.
I used this site as a blueprint for equipment, but purchased the following individually:
4Kw Aims 12Vdc-240V low frequency inverter
Two, 440W panels with tamarack racking on my well pump house roof
80A charge controller (could get away with 60A as I've never seen >65amps charging)
2X Ampere Time, 200AH 12V batteries in parallel

I took the house supply 240VAC and plugged it into the Aims inverter/charger
I installed a new sub panel which is fed from the inverter (now I have 120V out there as well!)
I adjusted my 9 zone sprinklers to run 2 zones a day, staggering them.
I have not seen my batteries below 40%.
Now I'm working on insulating and wiring 12V self heating as everything is in an un-insulated pump house.


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Complete Off-Grid Solar Kit - 4,000W 120/240V Output [2.4kWh-5.2kWh 12 - ShopSolar.com

RPK-MAX will power just about anything you need in an off-grid situation. Free shipping included! Shop Now. Experience flexibility and customization with our Remote Power Kits [RPK]. These solar kits were designed for those seeking a more traditional and customizable solar solution. With simple...
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OGK-8 kit
 
cigal.stephen said:
I just did what what you are asking about. I took my 1.5hp deep well off grid with grid backup. I have it set to prefer the batteries, and some may laugh at the 12v batteries running a 1.5hp pump, but I have no issues in 4 months. Pump only runs for about 70 seconds at a time to fill with pressure tank from 35-55psig.
I used this site as a blueprint for equipment, but purchased the following individually:
4Kw Aims 12Vdc-240V low frequency inverter
Two, 440W panels with tamarack racking on my well pump house roof
80A charge controller (could get away with 60A as I've never seen >65amps charging)
2X Ampere Time, 200AH 12V batteries in parallel

I took the house supply 240VAC and plugged it into the Aims inverter/charger
I installed a new sub panel which is fed from the inverter (now I have 120V out there as well!)
I adjusted my 9 zone sprinklers to run 2 zones a day, staggering them.
I have not seen my batteries below 40%.
Now I'm working on insulating and wiring 12V self heating as everything is in an un-insulated pump house.


shopsolarkits.com

Complete Off-Grid Solar Kit - 4,000W 120/240V Output [2.4kWh-5.2kWh 12 - ShopSolar.com

RPK-MAX will power just about anything you need in an off-grid situation. Free shipping included! Shop Now. Experience flexibility and customization with our Remote Power Kits [RPK]. These solar kits were designed for those seeking a more traditional and customizable solar solution. With simple...
shopsolarkits.com shopsolarkits.com
OGK-8 kit
Click to expand...
I recently installed a similar system for a customer. Although it is a 24V 4Kw Sungold and running a 3/4 horse deep well pump. The system has 2Kw of dedicated panels and two 12V Napa marine SLA. The little batteries provide inrush and then the solar takes over. They can pump water to their above ground tanks (100,000 gallons) all day.
 
brucenolan said:
Static water level is 140' pump is at 480' about 20' additional head to top of 3000 gal tank
Click to expand...
Thanks. My water is at 100ft and pump is sitting at 640ft. Well never draws down at all. Theres no reason for me to have a 7gpm pump. I think a 13 or 18 or even 25 would be totally fine on a 2hp motor. Im even considering going with a 13 or 18 and a 1 or 1.5hp motor.

I know thry put this model in because the well is so deep but it never draws down below 100ft static.
 
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