replacing solar three phase VFD system with single phase + Growatt inverter?

[schmolze]

I have an off grid property with the Franklin Electric SubDrive SolarPAK solar well pump system. The controller/inverter/VFD appears to have died, and Franklin Electric wants about $6k for a replacement!

The motor is a three phase 1.5 hp model, and I have a 2kW array dedicated to the well. I have two extra panels (500W) that are connected to an Ecoflow Delta Pro for my modest power needs as I'm building a cabin. The well is about 400 ft deep I believe.

I'm not too keen on shelling out $6k for a part that may fail again. A friend is willing to give me a Growatt 5000ES, and I'm considering switching over to a single phase well pump powered by the Growatt. I'm not sure I even need a battery since the pump only needs to operate when there is sun. I gather the start-up surge current is an issue, but it seems the Grundfos SQ line with the soft start feature may be an option?

Interested to hear if this sounds like a good idea, or if some other setup would work better.

 

[Samsonite801]

I have a neighbor here on our co-op who bought a Grundfos AC/DC pump that can take pretty much any power (AC or DC, with a wide voltage range), on the input, and he wires it straight to panels. He did also buy the special relay module (box) for it that can handle DC currents without arcing on disconnect.

He likes it a lot, it is soft-start.. I've never toyed with this myself yet, I still don't have my well dug yet, but am looking at this option. I think they are the Grundfos SQFlex line.

SQFlex

Renewable energy submersible pumps with built in inverter for solar, wind and AC powersource. Runs on both AC and DC voltage.

product-selection.grundfos.com

 

[schmolze]

I have a neighbor here on our co-op who bought a Grundfos AC/DC pump that can take pretty much any power (AC or DC, with a wide voltage range), on the input, and he wires it straight to panels. He did also buy the special relay module (box) for it that can handle DC currents without arcing on disconnect.

He likes it a lot, it is soft-start.. I've never toyed with this myself yet, I still don't have my well dug yet, but am looking at this option. I think they are the Grundfos SQFlex line.

SQFlex

Renewable energy submersible pumps with built in inverter for solar, wind and AC powersource. Runs on both AC and DC voltage.

product-selection.grundfos.com

Those do look like a nice option. I'm trying to weigh the pros and cons of the SQFlex vs. the standard SQ with a separate off the shelf inverter (Growatt in my case).

 

[v_brothers_ranch]

Not sure I have a perfect answer here but I think you might want to poke around and see if you can figure out the motor type (if you haven't already solved this!) I had one of those once and my understanding is that it was just a VFD that would allow for solar, and that if you wanted to run that thing off a cheaper traditional VFD for a 3 phase motor (which would run easily on a smaller inverter as it has slow startup) the trick is finding hte specs of that motor so you can program your VFD to that motor and save yourself from pulling it out of the well. Or get another company that does solar VFDs for 3 phase motors and see if they are compatible. A couple systems I have seen had a DC brushless vs. traditional 3 phase motor (induction I believe) so it needed an extra special VFD that was compatible. I'd call around and see if there is someone that could swap in replace the controller without touching the pump. Then in the future you still have all the options - add the inverter from your neighbor or keep it direct on solar... or run in hybrid I guess. If you find out the exact motor specs of what you have shoot me a message - I can only help if its like the one I did but who knows. good luck!

 

[smr.ruby]

I agree with @v_brothers_ranch . I definitely wouldn't replace the pump just because the drive failed. I think the SubDrives and Aquavar's (pump drives) are significantly over priced but that is at $1800-2k

$6K is with some labor or something to replace it right? Not just for the unit?

I have a 2HP Goulds 3-phase pump and I just setup my own VFD. An industrial grade 3HP ABB, Danfoss, or Yaskawa is < $500 and they are also a tiny footprint compared to the pump drives (not an outdoor enclosure though).

To the point of setting them up most of them have auto-tuning where they will run and try to detect pump parameters but even better if you can find the manual or specs for your pump. To the point of surge the VFD will eliminate any surge.