Best Inverter for deep well pump

WilliamC

New Member
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.
Which inverter specifically?
 

offgriddle

"FOREVER BEGINNING"
Which inverter specifically?
Inverter or possibly inverters, for example I like what Will did here with two MPP inverters connected in parallel, in phase with each other to make 240 VAC at 4,800 watts which would be plenty for me.
 

MichaelK

Solar Addict
My understanding is the Mpp inverters would be a very poor choice for running a well pump. I just watched another YouTube video of a guy testing a 48V Mpp 5000. It could not start his miter saw, which would not be as high a wattage as my well pump. You will be far better off getting an Outback Radian, or Schneider XW, both serious low-frequency inverters. For a well pump, you really need to focus your attention on the surge watts of whatever unit you buy.
 

WilliamC

New Member
My understanding is the Mpp inverters would be a very poor choice for running a well pump. I just watched another YouTube video of a guy testing a 48V Mpp 5000. It could not start his miter saw, which would not be as high a wattage as my well pump. You will be far better off getting an Outback Radian, or Schneider XW, both serious low-frequency inverters. For a well pump, you really need to focus your attention on the surge watts of whatever unit you buy.
I agree. I watched Wills video with interest but realized that these inverters are high frequency with very little surge capability. As I understand it you need to up-size the low frequency inverter so that any surge load is within the continuous rating of the inverter. That negates any cost advantage of the high frequency inverter. I would love to own either the Schneider or the Outback but the cost was a big factor. All I really need for continuous power is 4000 watts. both the Schneider and the Outback 4000 watt offerings fell just a tad short in the surge capability for my well pump. Either one of these would have fit in my budget. Unfortunately the next step up in size bumped the price beyond what I could justify.
I settled on the Aims 4000W UL 458/1012/1741 CSA inverter. This Inverter boasts a 30 second 12000W surge which handles my Well pump. It costs a bit more than the standard 4000W version. I think it will work for me as a Backup power source.

 

offgriddle

"FOREVER BEGINNING"
I never even considered that a pair of beefy looking MPP inverters creating a combined of 4,800 watts could falter in the face of surge current even if it's less than 4,800 watts. This is valuable information to consider when growing my solar power system, thank you all.

Size of Pump MotorRunning WattageStarting Wattage
1/3 HP750 to 8001,500 to 2,400
1/2 HP900 to 1,0501,800 to 3,150
3/4 HP1,500 to 1,8003,000 to 5,400
1 HP2,000 to 2,4004,000 to 7,200
1.5 HP2,500 to 2,8005,000 to 8,400
2 HP3,750 to 4,0007,500 to 12,000
3 HP5,000 to 5,50010,000 to 16,500
5 HP7,500 to 8,00015,000 to 24,000
7.5 HP10,000 to 11,00020,000 to 33,000
10 HP15,000 to 16,00030,000 to 48,000
 
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WilliamC

New Member
I never even considered that a pair of beefy lookig MPP inverters creating a combined of 4,800 watts could falter in the face of surge current even if it's less than 4,800 watts. This is valuable information to consider when growing my solar power system, thank you all.

Size of Pump MotorRunning WattageStarting Wattage
1/3 HP750 to 8001,500 to 2,400
1/2 HP900 to 1,0501,800 to 3,150
3/4 HP1,500 to 1,8003,000 to 5,400
1 HP2,000 to 2,4004,000 to 7,200
1.5 HP2,500 to 2,8005,000 to 8,400
2 HP3,750 to 4,0007,500 to 12,000
3 HP5,000 to 5,50010,000 to 16,500
5 HP7,500 to 8,00015,000 to 24,000
7.5 HP10,000 to 11,00020,000 to 33,000
10 HP15,000 to 16,00030,000 to 48,000
Good chart but it may be a little optimistic. My well pump runs at 2000W but start surges to 9000W. Actual measured.
 

MichaelK

Solar Addict
I never even considered that a pair of beefy looking MPP inverters creating a combined of 4,800 watts could falter in the face of surge current even if it's less than 4,800 watts. This is valuable information to consider when growing my solar power system, thank you all.

Size of Pump MotorRunning WattageStarting Wattage
1/3 HP750 to 8001,500 to 2,400
1/2 HP900 to 1,0501,800 to 3,150
3/4 HP1,500 to 1,8003,000 to 5,400
1 HP2,000 to 2,4004,000 to 7,200
1.5 HP2,500 to 2,8005,000 to 8,400
2 HP3,750 to 4,0007,500 to 12,000
3 HP5,000 to 5,50010,000 to 16,500
5 HP7,500 to 8,00015,000 to 24,000
7.5 HP10,000 to 11,00020,000 to 33,000
10 HP15,000 to 16,00030,000 to 48,000
This is why having numbers in hand BEFORE you start buying things is so important. BTW, I would say your chart above is overly optimistic. I have a 1hp pump, and it's MEASURED starting surge is 38A X 240V =9120AV. After getting my numbers, I was on the phone with each company's engineers to talk to them about what their units could power.

It's likely that four of your Mpp inverters couldn't start my pump. This is why the low-frequency inverters cost so much more. Because they are actually designed for serious off-grid loads, not just your TV.
 

offgriddle

"FOREVER BEGINNING"
This is why having numbers in hand BEFORE you start buying things is so important. BTW, I would say your chart above is overly optimistic. I have a 1hp pump, and it's MEASURED starting surge is 38A X 240V =9120AV. After getting my numbers, I was on the phone with each company's engineers to talk to them about what their units could power.

It's likely that four of your Mpp inverters couldn't start my pump. This is why the low-frequency inverters cost so much more. Because they are actually designed for serious off-grid loads, not just your TV.
HOLY TOLEDO, i didn't even know that low frequency and high frequency inverters existed, once again my hats off to you Michael for sharing this information and everyone else that takes the time to share what they know and of course ultimately Will for hosting this forum.

Thank You Thank You Thank You
 
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