Growatt 6K Off Grid Inverter Running a Deep Well Pump

Johnpaul2275

New Member
Hello All,

I am new to this forum. There is plenty of practical advice here for the novice DIY solar enthusiast.
So...... Here I am seeking advice as well as encouragement.

I want to set up an emergency solar back up system using lithium batteries, off grid inverter/inverters along with a solar array.
The system would power essential household appliances such as, refrigerator, freezer, toaster oven, TV, radio, computer, and
several lights during a 3 or 4 day black out.

The Big Issue for me is the Well. I have a 400' deep well using a 1 1/2 hp pump 220 volt AC. I have been told it will draw
between 30 to 40 amps on start up. I will get the specifics if you guys are interested.

At the moment I have a 9k Wen Generator using propane. It drives the house fairly well but i'm concerned about generator noise.
At half load (approx 4k) it produces 5% distortion into the main breaker box. I've tried running the well pump in conjunction with the
essential appliances and the well pump spits and sputters while the generator revs-up to max load. At this point I shut down the well
immediately. A (Clean) pure sign wave inverter is what I really need and one that can handle the surge loads demanded by a deep well pump.

I was thinking about installing:

2 Growatt 6k 48v off grid low frequency split phase inverters. One would be used strictly for 220 like the deep well and possibly hot water heater;
while the other would be use primarily for 110 household needs. The idea of having 2 inverters is redundancy or back up. If one goes
out, I still have a working unit for essential needs. I like the idea of low frequency inverters for surge power and the price per unit is more than
reasonable considering the functionality these inverters provide.

Note: Naturally I would consult a licensed electrician to check my work and to hook up to the main breaker box.

Question: Does anyone here have experience with the Growatt 6k off grid inverters?

Thanks all
 

Samsonite801

Solar Addict
First, check your actual voltage, is it 220v/110v or actually 240v/120v?

FYI, I have a 6000w inverter (low-frequency) I run off my Prius hybrid HV battery, and it wouldn't start my big air compressor, which is rated at 14.5a (running, not with inrush). I even put a soft-start capacitor replacement on it ( http://www.hypereng.com/ ) and it now turns for a few revolutions and tries but still won't start it (trips the inverter after about 3 seconds).

Do you have an amp clamp probe (capable of measuring inrush), which you could check to see your actual starting amps draw? I might start there, and try to gauge what your motor actually will draw at max inrush, as a starting point.

Then you would still need enough watts surplus on your inverter to be able power the pump, while your hot water heater element is also running.

Are these Growatt 6k stackable (to run together and get more amps)? What is the model number?
 
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Johnpaul2275

New Member
Hello Sam,

Thanks for the reply. The inverter model number is the N6000L-48SP. This particular unit is not stackable, but as you know the other
units that Growatt offers; that are stackable, are not low frequency. I really want the big transformer to aid in power draw.

I didn't think about a soft start capacitor. Great idea. I will check into it.

I do have a clamp meter that measures both AC and DC. I will take some actual measurements on the system to see what
the pump really draws in operation. Another great idea!

As far as the water heater goes. One step at a time. lol but I will take preliminary measurements for future reference.

DavidPoz Has a YouTube Channel https://www.youtube.com/user/greasybrothers/videos He has good ideas and I watch him from time to time
But he doesn't specifically key on well pumps per say. That is one of the reasons I am here on this forum.

What is the name/model of your 6k inverter.
 

Samsonite801

Solar Addict
Hello Sam,

Thanks for the reply. The inverter model number is the N6000L-48SP. This particular unit is not stackable, but as you know the other
units that Growatt offers; that are stackable, are not low frequency. I really want the big transformer to aid in power draw.

I didn't think about a soft start capacitor. Great idea. I will check into it.

I do have a clamp meter that measures both AC and DC. I will take some actual measurements on the system to see what
the pump really draws in operation. Another great idea!

As far as the water heater goes. One step at a time. lol but I will take preliminary measurements for future reference.

DavidPoz Has a YouTube Channel https://www.youtube.com/user/greasybrothers/videos He has good ideas and I watch him from time to time
But he doesn't specifically key on well pumps per say. That is one of the reasons I am here on this forum.

What is the name/model of your 6k inverter.

Just FYI, not all amp clamp meters have an 'Inrush' measurement feature on them, so you will have to check the manual on yours. A lot of them won't have volt sample-rate fast enough, or record highest reading sampled.

I wouldn't necessarily get fixated on a low-frequency inverter to start big motors. Low frequency are also less efficient inverters too. I used to think it mattered a lot, but reading and learning more I find some of the biggest powerhouse inverters like the Sol-Ark 12k are high frequency, and also come with less idle draw, and higher efficiency. And Sol-Arks are considered one of the best inverters on the market, and the only ones I know of that can be ordered with EMP hardened circuits in them.

The MPP LV6548 pair I bought from MPP Solar, the rep told me they are actually a combination of high frequency still with transformer, and it can surge to double amps for 5 seconds. Of course I have not tried my MPPs yet, still in the boxes until I get my shop built on the ranch property.


Here is what the rep told me about the MPP LV6548s:
"
LV 6548 is a 120vac 6500w inverter 48v designed with high PV input 250vdc.
And with built-in two MPPT charge controllers and WiFi card.
Can support batteryless operation when under single inverter usage.
It will also allow to work as split phase 240/120v AC output when user put 2 or up to 6 units of same inverter model in parallel.
"

Then I said:
"
How many watts do you get with 2 in parallel? How many watts on the 240v and on the 120v? Can the 120v power be unbalanced? Can the 240v start up a 14.5a 3.7 hp air compressor? Is this a low frequency inverter or high frequency inverter?
"

Then the MPP rep said:
"
These are High frequency inverter, and still with transformer built in .
As long as your AC load size will not exceed the size of inverter, it will work fine .
Inverter is designed in 6500w continuous power. Surge power 13kW ( withhold 5 seconds ).
And for 2 inverter in parallel , it will be a 13kW inverter system / surge power 26kW ( withhold 5 seconds ).
For working under a 120v AC, the supported output AC current is 118.18a , or under 240v AC output , it is 54.16a .
We have many different model of inverter designed in similar way, unbalance power is confirmed not an issue.
"

I might consider looking at stackable inverter solutions, don't worry so much about low frequency or high frequency, just make sure they are rated with enough margin to run your desired loads. And motor soft-starters always makes sense to run with any inverter, as it smooths out the sudden inrush surges by up to 70%.
 
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Johnpaul2275

New Member
Wow! Thanks again. I will keep all of this in mind. I have seen the MPP inverters on YouTube but looked over them
because they are not low frequency. After reading your post, I will take another look at the MPP LV6548 inverter.

I know that the Growatt 12k is a beast and can drive my house for most of our needs; but if for some reason it goes out
I am dead in the water. In the long run, using 2 MPP LV6548 in parallel might be the perfect solution for my needs.

Good thing I posted my thoughts here in this forum. I will keep everyone posted on future events.
 

Wellbuilt

Solar Addict
How old is your well pump , maybe just change the pump to a soft star unit .
I use a Grundfos unit and pump from 730 feet , it runs effortlessly off a 3600watt inverter
 
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