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Advise on emergency backup with well pump

D

DonnieT

New Member
Joined
Oct 3, 2024
Messages
44
Location
North MISSISSIPPI
I’m want to build a generator for emergency backup, I do have a 3/4hp 240v 2-wire well pump that runs at 7.4a per leg. I didn’t check inrush but I will in the morning. I’m looking at the Sigineer 48v 12k split phase low frequency inverter/charger/MPPT and Growatt 48v 12k splf model too .Im ordering 10 Aptos 400w bifacials and also 16-304ah lifepo4 cells with 200aBMS. Besides the well pump I want to run other loads in the house as well ,during an outage ,nothing too big all LED on lights. I am an electrician and have been for 30+ years but NEVER done any solar. I know the math ohms law and such ,just not how it all correlates .i will continue to grow the battery storage as money allows just don’t think a 6k will suit my needs and don’t want to outgrow it . Any thoughts?thanks
 
Expect 5X INRUSH on pump.

Sigineer LF is an absolute beast. Their 24V/6kW unit started my neighbor's Grundfos 3hp deep well pump with a run current of 18A.

They are also HUNGRY. They consume power and will burn 200W just being on and powering no loads. That's 4.8kWh/day or about 31% of the capacity of your 304Ah battery just to feed the inverter itself.

It will also take about 25% of your array to feed the beast.

Just remember to include the 200W load of the inverter 24/7 when you do your energy audit.
 
Nice plan. I recommend high quality equipment with low idle draw, like victron transformer based units.

Why only 10 panels?
 
I have replaced two sigineer inverters in the last 8 months. One because of the amount of power consumed by the inverter while sitting idle.
The other was from a manufacturing defect that caused a short and let the magic smoke out of it.

One was replaced with a midnite AIO, the midnite inverter is a work of art compared to the sigineer.
The other was replaced with a Victron paired to an auto transformer, and a victron charge controller. Also a very high quality.

I am a bit old school (older) and wouldn't install a system unless the solar panel output watts were approximately equal to 80% of inverter max output. Had a lot of happy customers because of this.
With a cheap as solar panels are now, I would reccomend the solar panel output watts to be able to match the inverter output watts.
 
1201 said:
Nice plan. I recommend high quality equipment with low idle draw, like victron transformer based units.

Why only 10 panels?
Click to expand...
Thanks for the tip, Because the $6000 for all the other stuff wiped my wallet out this month and I just want to get started this month ,plan to get many more just need the money to accumulate back up
 
sumpower said:
I have replaced two sigineer inverters in the last 8 months. One because of the amount of power consumed by the inverter while sitting idle.
The other was from a manufacturing defect that caused a short and let the magic smoke out of it.

One was replaced with a midnite AIO, the midnite inverter is a work of art compared to the sigineer.
The other was replaced with a Victron paired to an auto transformer, and a victron charge controller. Also a very high quality.

I am a bit old school (older) and wouldn't install a system unless the solar panel output watts were approximately equal to 80% of inverter max output. Had a lot of happy customers because of this.
With a cheap as solar panels are now, I would reccomend the solar panel output watts to be able to match the inverter output watts.
Click to expand...
That’s good to know I haven’t clicked the button on the inverter yet I wanted to here what the folks here had to say first., I’m old school too and old .i plan to build this thing up as I go and as money rolls in. My wife is finishing her masters degree so most of the extra $$ goes to university tuition right now
 
sumpower said:
I have replaced two sigineer inverters in the last 8 months. One because of the amount of power consumed by the inverter while sitting idle.
The other was from a manufacturing defect that caused a short and let the magic smoke out of it.

One was replaced with a midnite AIO, the midnite inverter is a work of art compared to the sigineer.
The other was replaced with a Victron paired to an auto transformer, and a victron charge controller. Also a very high quality.

I am a bit old school (older) and wouldn't install a system unless the solar panel output watts were approximately equal to 80% of inverter max output. Had a lot of happy customers because of this.
With a cheap as solar panels are now, I would reccomend the solar panel output watts to be able to match the inverter output watts.
Click to expand...

sunshine_eggo said:
Expect 5X INRUSH on pump.

Sigineer LF is an absolute beast. Their 24V/6kW unit started my neighbor's Grundfos 3hp deep well pump with a run current of 18A.

They are also HUNGRY. They consume power and will burn 200W just being on and powering no loads. That's 4.8kWh/day or about 31% of the capacity of your 304Ah battery just to feed the inverter itself.

It will also take about 25% of your array to feed the beast.

Just remember to include the 200W load of the inverter 24/7 when you do your energy audit.
Click to expand...
Wow that is a hungry unit ,do you know anything about Genetry inverters?
 
For now since you are in the planning stage. I’d go ahead and buy the Emporia View 3 and install it in your breaker panel. This can give you a real world idea of exactly what you’re using and how much power you can conserve in priority only exercise. It can also be used to control smart switches and plugs. I thought it would be kinda junky but I’m surprised buy it’s accuracy. The only thing is it’s cloud based so you got that data out there. Of every app/device I own, this was the easiest to register, access and zero issues after two years (view 2 older units). If you have an older tight panel the sensor can be a challenge to install so I had to temporarily remove some breaker wires to place some current sensor. The antenna can be out of a knockout and the WiFi signal is the strongest yet the furthest from the modem. After Solar Assistant, it probably one of my best investments for initial info but it doesn’t get used as much as it used to. Still nice check things remotely, like did someone remember to put the clothes in the dryer.?
 
sunshine_eggo said:
Expect 5X INRUSH on pump.

Sigineer LF is an absolute beast. Their 24V/6kW unit started my neighbor's Grundfos 3hp deep well pump with a run current of 18A.

They are also HUNGRY. They consume power and will burn 200W just being on and powering no loads. That's 4.8kWh/day or about 31% of the capacity of your 304Ah battery just to feed the inverter itself.

It will also take about 25% of your array to feed the beast.

Just remember to include the 200W load of the inverter 24/7 when you do your energy audit.
Click to expand...
I have an AIMS 24v 4k LF, I think its made by Sigineer. Shaped like a twinkie. The transformer is MASSIVE. It pulls about 90w idle and probably under 80% efficient on its best day. Needless to say, its only on when I'm running the air compressor, and other power hungry tools. Luckily my well is a soft start and runs off another inverter otherwise that AIMS would eat all my solar.

If I had it just on a well, I would make the inverter cycle with the pump. That would save a ton of power. Yes, its cycling the inverter more but I dont think its worth the power trade-off
 
sunsurfer said:
I have an AIMS 24v 4k LF, I think its made by Sigineer. Shaped like a twinkie. The transformer is MASSIVE. It pulls about 90w idle and probably under 80% efficient on its best day. Needless to say, its only on when I'm running the air compressor, and other power hungry tools. Luckily my well is a soft start and runs off another inverter otherwise that AIMS would eat all my solar.

If I had it just on a well, I would make the inverter cycle with the pump. That would save a ton of power. Yes, its cycling the inverter more but I dont think its worth the power trade-off
Click to expand...

Yep. AIMS = Sigineer made
 
sunsurfer said:
I have an AIMS 24v 4k LF, I think its made by Sigineer. Shaped like a twinkie. The transformer is MASSIVE. It pulls about 90w idle and probably under 80% efficient on its best day. Needless to say, its only on when I'm running the air compressor, and other power hungry tools. Luckily my well is a soft start and runs off another inverter otherwise that AIMS would eat all my solar.

If I had it just on a well, I would make the inverter cycle with the pump. That would save a ton of power. Yes, its cycling the inverter more but I dont think its worth the power trade-off
Click to expand...
I have the sungold 24/4k running a standalone 3/4hp. Both it and the AIMS have soft start on the power saver mode. As it's a standalone unit, the idle usage is a non issue in power saver.
 
DIYrich said:
I assume you have a large tank for the well water. Consider how long the pump has to run each day to top off the tank.

Manually turn on/off the Sigineer to run the pump each day during an outtage. Use one of the other inverters for your normal needs. That will cut down on the standby losses.
Click to expand...

This is how my neighbor runs his. 2000 gallons above ground. Sigineer on when pumping desired, breaker closed to power pump. Fill-er-up and shut it down. 2-3 times/week.
 
Being emergency backup, you're only going to turn it on when you need it right? Personally, I wouldn't worry about the idle consumption when you have 4000w of solar and its part time use.

I have been happy with my Aims inverters and wouldn't hesitate to buy a Sigineer product. I currently have a 6k split phase/24v and 4k/24v Aims along with a new 3k/24v Sigineer. All are solid, no frills, high surge inverters that (so far) can take a beating. My oldest one is the 4k and its over 7 years old.

Now, going larger than a 6k inverter....... Id be looking at the Midnite Rosie 7k or if going larger than that it makes sense to parallel Victron in split phase.
 
seneysolar said:
Being emergency backup, you're only going to turn it on when you need it right? Personally, I wouldn't worry about the idle consumption when you have 4000w of solar and its part time use.
Click to expand...
200w is 4.8kWh per day. That is more than 10% of my house daily consumption.

 
DIYrich said:
200w is 4.8kWh per day. That is more than 10% of my house daily consumption.
Click to expand...
Right, but for a backup system and a 4k array, he will be caught up the next day in an hour of PV production.
Im in the same boat, and my batteries are in float by 1pm, life is good.
Assuming hes not running water all day for irrigation purposes and no other large continuous loads.
If the OP decides to run air conditioning, bake a turkey and connect electric hot water, he will need more pv and battery regardless of his inverter choice.
 
BarracudaBob said:
I used the Growatt SPI 2200 TL2-HV 2.2KW on a 1.24 HP single phase capacitor start pool pump with zero issues. There are many post on this form about it. They make it in larger output versions. Never tried it on a well pump. It will switch from Shore Power to PV and uses PWM to ramp up speed.
Click to expand...

Very curious. You say it acts like a VFD? Does it actually modulate the frequency?
 
sunshine_eggo said:
Very curious. You say it acts like a VFD? Does it actually modulate the frequency
Click to expand...
YES, it ramped up the frequency to full and if not enough sun it would slow down and hold. No sun it would stop, wait, and switch to grid. I put a timer on the grid and the salt water generator to only run during peek heat time. In dawn or dusk it would run up and down until it quit. It worried me in the beginning but was ok after that. I even ran the same panels on another MPPT and it worked fine until the grid turned on and failed out GFI so dedicated panels only. It did overvoltage on me under the set limit. I believe it was around 380VDC it would fault out. Had it on 3.6K array for playing around.
 
BarracudaBob said:
YES, it ramped up the frequency to full and if not enough sun it would slow down and hold. No sun it would stop, wait, and switch to grid. I put a timer on the grid and the salt water generator to only run during peek heat time. In dawn or dusk it would run up and down until it quit. It worried me in the beginning but was ok after that. I even ran the same panels on another MPPT and it worked fine until the grid turned on and failed out GFI so dedicated panels only. It did overvoltage on me under the set limit. I believe it was around 380VDC it would fault out. Had it on 3.6K array for playing around.
Click to expand...

Yeah... A little digging into the manual certainly implied that. My neighbor just did a big upgrade and got a Grundfos CUE 100 20 VFD (AC single phase and DC input capable) and a new 3 phase 2hp pump. It's amazing, but it's about 6X more expensive than the Growatt.

IMHO, it looks like the Growatt has pretty similar capabilities, but I can't find a setting for minimum frequency. The Grundfos pump explicitly requires the motor not be run below 30Hz.

The Grundfos is astoundingly simple. App interface with Bluetooth to program/monitor the unit. Found that 58Hz was his sweet spot for balancing gpm vs. load at about 5 gpm at about 2100W consumption.
 
It started up pretty low and it wasn't uncommon to see it in the upper 30 hz in dim sun. If the slow running and stopping isn't going to work for you you can also put a timer on the pump Tank Fill contacts. I have home automatic relay on it that would start/stop it otherwise if you bridge the connection it gets flaky at dim light. I wanted to tie it to a 240V breaker and have the pool timer do it but never got there. Left the chlorinator on the utility time clock. It didn't like the frequency change. Pump no issues. Funny is it used to squeal when on the grid but now it doesn't.
 
DonnieT said:
I’m want to build a generator for emergency backup, I do have a 3/4hp 240v 2-wire well pump that runs at 7.4a per leg. I didn’t check inrush but I will in the morning. I’m looking at the Sigineer 48v 12k split phase low frequency inverter/charger/MPPT and Growatt 48v 12k splf model too .Im ordering 10 Aptos 400w bifacials and also 16-304ah lifepo4 cells with 200aBMS. Besides the well pump I want to run other loads in the house as well ,during an outage ,nothing too big all LED on lights. I am an electrician and have been for 30+ years but NEVER done any solar. I know the math ohms law and such ,just not how it all correlates .i will continue to grow the battery storage as money allows just don’t think a 6k will suit my needs and don’t want to outgrow it . Any thoughts?thanks
Click to expand...
How old is your pump , what's the depth ?
Might consider installing a grundfos sq pump , no start up / inrush amps ( soft start built in ) .
I ended up going with an sq pump it let me use a smaller inverter and battery bank . Might be worth the trade off .
 
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