well pump

sewerattseweratt Registered Users Posts: 1
looking to run a well pump 1 hp 230 volt single phase 13amps on start up drops to 9.5 on the run. wanting to run it all day to help keep my pond full.  doesn't have to run at night not wanting to buy expensive battery set up   has about 75 ft of lift and then gravity feed from top of well down to pond 

Any thoughts

Comments

  • BB.BB. Super Moderators, Administrators Posts: 32,639 admin
    Welcome to the forum Seweratt.

    That is a lot of energy... Something like:
    • 9.5 amps * 240 VAC * 0.8 Power Factor (guess) = ~1,824 Watts average load
    • 1,824 Watts * 10 hours a day = 18,240 WH = 18.24 kWH per day
    And what is your electric bill? Say $0.15 per kWH (ranges from under $0.10 to over $0.40 depending on where you live and your local state's energy policies:
    • 18.24 kWH per day * $0.15 per kWH * 30 days per month = $82.08 per month (wild guess)
    Finding very efficient well pumps (and motors) can save you a lot of money.

    Or you can buy a very efficient solar friendly pump that can even run directly from solar panels (pump when the sun is up)--Not cheap for the pumps.

    There are now VFDs (variable frequency drives) that can run directly from solar panels. Are becoming more popular with farmers and other countries where the option are diesel or petrol powered gensets.

    Some discussions/links to solar water pumping:

    https://forum.solar-electric.com/discussion/comment/191136#Comment_191136

    Moving water can consume quite a bit of energy... Any way you can reduce the water loss from the pond (or is the pump used as an irrigation source?)?

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • MichaelKMichaelK Registered Users Posts: 225 ✭✭✭
    edited June 2020 #3
    What kind of instrumentation did you use to come up with your pump numbers?  I would suspect they are wrong.  I'm powering a 1hp 240VAC Grunfos pump, so I have very good data on what a 1hp pump needs.  The 9.5 amps running number looks about right, but I very much question the 13amps startup number.  Was this with a regular clamp meter?  Did it blink at 13 for one second before dropping down to 9.5A?  A regular meter does not respond fast enough to capture the real starting amperage.  You need a meter that has "inrush current" capability.  I would predict your real startup amperage to be 37 to 40 amps.
    In any case, there are both AC and DC solutions to your problem.  One way is to build an AC system capable of running that pump.  With AC, about 3000W of panels might run your pump from about 9am till about 3pm.  I have 4500W of panels on rotating mounts, so I can pump from about 8am till 4pm.
    The DC method is to replace the pump with a DC version and attach it to a solar pump controller,  The controller starts the pump sloooowly in the morning, reaches full power at noon, and then slowly tapers off in the afternoon.  The pump manufacturer will have charts telling you how many watts are needed for so many gallons at such and such depth.
    The DC version will let you set it up and walk away.  You just need to check every couple of days to see if output is what you expected.  The AC version will need monitoring in real-time, unless you have an automatic timing system.
    System 1) 15 Renogy 300w + 4 250W Astronergy panels,  Midnight 200 CC, 8 Trojan L16 bat., Schneider XW6848 NA inverter, AC-Delco 6000w gen.
    System 2) 8 YingLi 250W panels, Midnight 200CC, three 8V Rolls batteries, Schneider Conext 4024 inverter (workshop)
  • mcgivormcgivor Solar Expert Posts: 3,854 ✭✭✭✭✭✭
    MichaelK said:
    What kind of instrumentation did you use to come up with your pump numbers?  I would suspect they are wrong.  I'm powering a 1hp 240VAC Grunfos pump, so I have very good data on what a 1hp pump needs.  The 9.5 amps running number looks about right, but I very much question the 13amps startup number.  Was this with a regular clamp meter?  Did it blink at 13 for one second before dropping down to 9.5A?  A regular meter does not respond fast enough to capture the real starting amperage.  You need a meter that has "inrush current" capability.  I would predict your real startup amperage to be 37 to 40 amps.
    In any case, there are both AC and DC solutions to your problem.  One way is to build an AC system capable of running that pump.  With AC, about 3000W of panels might run your pump from about 9am till about 3pm.  I have 4500W of panels on rotating mounts, so I can pump from about 8am till 4pm.
    The DC method is to replace the pump with a DC version and attach it to a solar pump controller,  The controller starts the pump sloooowly in the morning, reaches full power at noon, and then slowly tapers off in the afternoon.  The pump manufacturer will have charts telling you how many watts are needed for so many gallons at such and such depth.
    The DC version will let you set it up and walk away.  You just need to check every couple of days to see if output is what you expected.  The AC version will need monitoring in real-time, unless you have an automatic timing system.

    The inrush occurs when the rotor is at stall, usually for less than 10 miliseconds, gradually dropping for around 70 miliseconds until the run current settles to its rated value, which will be influenced by load, the greater the total head the higher the run current. 

    These are the values taken from a 230V 1hp single phase submersible pump with a total head of ~24 feet, inrush 42A, run 4.6A, maximum rated current is 8.9A. The biggest problem using an AC single phase pump with solar is the inrush, since an inverter would be required a battery would also be required along with a charge controller. The battery would have to be sufficiently sized to not only support the running when a cloud passes for example, but also the inrush demands during start up. In the above example the 42A inrush at 230V would mean ~420A at 24V which is what I was using, if the battery is too small in capacity the voltage will drop causing the inverter to fault, needless to say the inverter itself needs to be capable of supporting the required current demands

    The DC pump is one option usually with a DC - DC controller to restrict low voltage starting attempts, this  eliminates the need for the battery, and inverter. The other is a solar MPPT / VFD driving a 3 phase AC pump, the benefit of this method is the pump will operate at lower speeds outside the solar peak allowing better overall pumping performance.
    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery with Battery Bodyguard BMS 
    Second system 1890W  3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah LFP 24V nominal battery with Daly BMS, used for water pumping and day time air conditioning.  
    5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
  • mike95490mike95490 Solar Expert Posts: 9,581 ✭✭✭✭✭
    You have to rethink your power usage, the numbers look way rong


    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
    gen: http://tinyurl.com/LMR-Lister ,

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