Yet another newbie water pumping question

azrcazrc Solar Expert Posts: 43
For one of the wells that I would like to do (140', 3", 7hrs sun/day, 100% off grid), the users would like the maximum amount of water and to be able to occasionally sell some to neighbors for farming.

The first thing I came across in searching are the DC, brushless panel to pump solution (1HP pump), but then I was thinking that there will is a 3kw outback inverter available. Since 230v AC pumps are less than 1/2 the price of a comparable DC option, does it make sense to go this way and power a 1.7HP pump from the inverter and just buy extra panels with the savings? There are more system losses but in the majority of time when the pump is not being used you have extra energy to the buildings (not that they use that much, but would give them the option).

I'm assuming the outback (3048T) would not have a problem delivering this power? The pump is 230v, but I think I can just add a transformer to boost the voltage (are there any problems with doing this)?

I've read the information at NAWS, but would like to hear experiences from anyone who does or attempted this.

Thanks again for all of the help.

Comments

  • Dave AngeliniDave Angelini Solar Expert Posts: 5,956 ✭✭✭✭✭
    Re: Yet another newbie water pumping question

    Assuming your outback inverter/charger will run a fairly deep well pump is what I did once. Never again though! Do the math on the pump requirements and quadruple the amount for surge if you want the inverter to last. Even then, I would use an XW from Xantrex because they are built for deep wells and the SW before as well.
    "we go where power lines don't" Sierra Mountains near Mariposa/Yosemite CA
     http://members.sti.net/offgridsolar/
    E-mail [email protected]

  • stephendvstephendv Solar Expert Posts: 1,571 ✭✭
    Re: Yet another newbie water pumping question

    Another option is to use a variable frequency drive (VFD) that converts single phase 110V into 3 phase 230V, and then use a 3 phase pump. Or transformer for 110V to 230V then 230V single to three phase VFD (which are more common) and then 3 phase pump.
    The VFD prevents the starting surge and prolongs motor life.

    These have been discussed before, try a search for "variable frequency drive".
  • azrcazrc Solar Expert Posts: 43
    Re: Yet another newbie water pumping question
    Assuming your outback inverter/charger will run a fairly deep well pump is what I did once. Never again though! Do the math on the pump requirements and quadruple the amount for surge if you want the inverter to last. Even then, I would use an XW from Xantrex because they are built for deep wells and the SW before as well.

    One of the pumps that I'm looking at is the Grundfos 30SQ10-130 (claims of 28GPM at 140') and has a 'softstart' feature. Big inductor? Anyway, one of my routers has this (very nice). Do you know if this would be nicer to the inverter?

    Thanks for the info.
  • azrcazrc Solar Expert Posts: 43
    Re: Yet another newbie water pumping question
    stephendv wrote: »
    Another option is to use a variable frequency drive (VFD)

    Thanks, I've looked at these and what I was thinking about, but then found higher capacity 'non-solar' pumps and was wondering the feasibility of going that route.
  • Dave AngeliniDave Angelini Solar Expert Posts: 5,956 ✭✭✭✭✭
    Re: Yet another newbie water pumping question
    azrc wrote: »
    One of the pumps that I'm looking at is the Grundfos 30SQ10-130 (claims of 28GPM at 140') and has a 'softstart' feature. Big inductor? Anyway, one of my routers has this (very nice). Do you know if this would be nicer to the inverter?

    Thanks for the info.

    The DC pumps are fine for what you want. The 240vac is where you get into trouble fast with your inverter. Good Luck!
    "we go where power lines don't" Sierra Mountains near Mariposa/Yosemite CA
     http://members.sti.net/offgridsolar/
    E-mail [email protected]

  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Yet another newbie water pumping question

    Just a couple of notes about using the OB 3048.
    The 3kW rating is slightly optimistic for continuous use.
    The power surge on that 1.7 HP pump is no doubt going to be over 4kW.
    As Dave said, it'll fry the inverter. Maybe not right away, but it's pretty rough demand.
    Also, step-up transformers can create their own problems. Especially if not wired right.

    Anytime you're planning off-grid pumping it will pay to investigate changing the pump to exactly suit the needs rather than just trying to come up with the equivalent grid power to run an "off the shelf" unit. The bigger the pumping requirement, the more it will pay.

    In case you're wondering, my FX3524 has a step-up transformer to run the 240 VAC 1 HP digester pump. It works, but it doesn't have to lift water 100+ feet and it only runs 1 minute or so per day.
  • azrcazrc Solar Expert Posts: 43
    Re: Yet another newbie water pumping question
    Just a couple of notes about using the OB 3048.
    The 3kW rating is slightly optimistic for continuous use.
    The power surge on that 1.7 HP pump is no doubt going to be over 4kW.

    Anytime you're planning off-grid pumping it will pay to investigate changing the pump to .

    Wouldn't an appropriate inrush limiter eliminate this problem? I've worked on big power supplies in the past that could (and did) take down a building because turning the thing on looked just like a short until we limited current on startup. Just learning...it's a whole new area for me.

    Thanks
    :D
  • mike95490mike95490 Solar Expert Posts: 9,298 ✭✭✭✭✭
    Re: Yet another newbie water pumping question

    Motors, pumps with 200' of water stacked up on top of them, either need a slow-start VFD 3 phase circuit, to get them spinning, or you really have to punch the STARTER WINDING hard for a couple seconds, to get it spinning to normal speed where the RUN winding can take over. Trying to limit the starter winding will just burn it up. That is the big inverter killer surge. There are 2 wire and 3 wire single phase pumps that differ in their start winding control, 3 wire is supposed to be just a little gentler on inverters.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
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  • Dave AngeliniDave Angelini Solar Expert Posts: 5,956 ✭✭✭✭✭
    Re: Yet another newbie water pumping question

    Nice Mike! And I'll add that most designers installers and welldriller folks do not look kindly at playing R&D with a pump that is "way down there". If there is not 10 years+ of history with a system nearly as critical as your battery they walk. I certainly do! If you want to pump deep water fast it will cost you !
    "we go where power lines don't" Sierra Mountains near Mariposa/Yosemite CA
     http://members.sti.net/offgridsolar/
    E-mail [email protected]

  • wild01wild01 Solar Expert Posts: 100 ✭✭✭
    Re: Yet another newbie water pumping question
    azrc wrote: »
    One of the pumps that I'm looking at is the Grundfos 30SQ10-130 (claims of 28GPM at 140') and has a 'softstart' feature. Big inductor? Anyway, one of my routers has this (very nice). Do you know if this would be nicer to the inverter?

    Thanks for the info.


    that is at 0 psi

    a good grundfos sq spec manual can be found here

    http://www.pumpsofoklahoma.com/Websites/pumpsofoklahoma/images/pdfs/sqbook.pdf

    don't know if they are a good company just the first real graph I found!

    looks like the best you will do with that setup is a 22SQ/SQE10C-190
    which will put out 16.5 gpm @ 140feet with 40 psi of pressure use a 20/40 pressure switch and it should work for you.

    I have a 5gpm 1/2 hp sq and it really does have a zero surge start, they work great and if my 1/2 hp pump is any indication, I would expect this pump to pull 2kw when running full blast ( my 1/2hp NEVER pulls more than 1kw) again zero surge start.

    I would bet money th ob inverter will push this fine as my vfx3236 pushes my 1/2 hp pump fine even when I am using my 1800w induction cooktop on high.

    the sq I use actually starts out lower than 1kw (about 750w) and climbs there over several seconds.

    well that's 3 posts in a row plugging the sq guess I better back off

    swear I'm not affiliated w/grundfos in any way I just love my well pump. It works exactly as advertised. and I'm tired of seeing the extremely overcomplicated systems many installers push for, when the sq is reasonably priced and works great. (I know it's not as efficient as some but it is cheaper and higher quality take the money you save and buy more panels)
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