Need some solar help and advice

Discussion in 'Off Grid Living' started by T. Riley, Jul 24, 2016.

  1. T. Riley

    T. Riley Monkey+++

    I need some help designed a specific use solar system for my well. I want to aim for 300 gallons a day. The pump is 230v and draws 9.6 amps when running. The draw down on my storage tank is 30 gallons before the pump cycles. It takes one and a half minutes for it to refill the tank. The way I see it the pump will have to run 10 times per day x 30 gallons = 300 gallons. At 1.5 minutes that’s 15 minutes run time per day. 230*9.6 = 2,208 watts / 4 = 552 watts per day. The average solar radiation at my location 5.12 hours (3.67 low/5.90 high). Doubling the watts makes it about 1200 watts per day. I was figuring on two 300 watt 12v panels, an Outback FlexMax 60 charge controller, two Vmaxtanks 125ah batteries and I have no idea about the inverter. These components will be backups to my existing small solar system. Any suggestions, criticism, calculation corrections are welcome. You won’t hurt my feelings.
    stg58 likes this.
  2. BTPost

    BTPost Stumpy Old Fart,Deadman Walking, Snow Monkey Moderator

    If it were ME, designing this system, I would be using 2 ea. L16HD, 6 Vdc, 400 AH Batteries in Series for the Battery Bank. Ot at least a Pair of T-105, 6 Vdc, 225 AH, GolfCart Batteries... Batteries in Parallel, are an issue... If you need more AmpHours, buy Bigger Batteries, rather than Paralleling smaller Batteries....
  3. ghrit

    ghrit Bad company Administrator Founding Member

    Agree. Paralleling batteries is a matter of luck that they are identical to the molecule and will age identically. (Slight exaggeration, but not much.)

    I did not check your numbers, but if they are accurate, I'd be inclined to get a larger pressure tank. Cycling the pump for those short operating times could (not certainly) give some problems. Better to run longer and less often.
  4. DKR

    DKR Raconteur of the first stripe

    You might want to consider going up to a 24 volt or even a 48 volt DC feed. A pure sine wave convertor might cost more at initial purchase, it does give you the option for use other than the well pump.

    Inverter Sizing for Well Pump
    This site looks specifically at well pump Solar systems, you may find it useful.

    The math (9.6 A X 230 VAC) says a 2.5 KW is the minimum and I would strongly suggest getting an inverter than can be paired with additional units for more power.
  5. oil pan 4

    oil pan 4 Monkey+++

    A good quality pure sine inverter that can take 24v and turn it into 240v at 2.5kw is going to cost at least $1,000 and go up to $2,000.
    The start up surge will be 3 to 5 times the rated name plate amps.
    Is there any way that you could use DC pump?
    A good DC pump will only cost a few hundred $.
  6. Tevin

    Tevin Monkey+++

    Basically you need to come up with 2200 watts for 15 minutes per day. That's not too bad, but it would take a lot of battery to do it the way you describe. Two 125 aH batteries are not enough to produce 2200 watts for more than maybe a few seconds.

    A rough estimate would be 10-12 batteries, which comes out to each battery producing about 200 watts when the pump runs. It is about the max you could expect from a 125 aH battery, and even that's a generous guess.

    600 watts of solar normally would not be enough to hold up that many batteries, but it might work if the batteries are only used to run the pump 15 minutes a day.

    I would consider getting a smaller pump and running it longer. You would also be able to get away with a smaller inverter. The overall daily power drain would be about the same. 1100 watts for half an hour is the same energy as 2200 watts for fifteen minutes, and it's a lot easier to do.

    Another, easier, less expensive option is to run the pump off a gas generator. You would only need to run the generator when the water level gets low.

    A last choice would be to get enough solar to run the pump without much if any help from the batteries. You would be limited to running the pump only in strong sun but it would let you off the hook for a lot of batteries. Technically, you could have one small battery to support the inverter and let the solar do the rest. Solar panels are mighty cheap these days.

    @oil pan 4 is right. A 240 volt inverter is going to cost you serious money. Lastly, this type of project is not for noobs. If you do not have a lot of experience with electric and proper wiring practices, get someone knowledgeable to help you or hire an electrician.
    T. Riley likes this.
  7. T. Riley

    T. Riley Monkey+++

    Maybe 300 gallons of water storage and running the pump once a day for 15 minutes with my propane generator to fill it would be a better option. I could then run a RV 12 volt water pump to feed the water lines to the house with much less solar. I have 800 gallons of propane and a 10kw genset.
    sec_monkey likes this.
  8. Cruisin Sloth

    Cruisin Sloth Special & Slow

    9.6 amps is AC @ 230Vac ?
    30 gallon tank is a squeeze pressure tank ?
    Depth & type of well
    Where you are in location , Not your address , but in USA TX or AK is totally different in harvest views
    the higher the battery voltage the more watts can be harvested in the same time .
    Location says amount of time to harvest .
    and you measured amps how ?

    @Too Country
    You might want to follow , because your dreaming on some of your posts .

    Last edited: Jul 24, 2016
    sec_monkey likes this.
  9. BTPost

    BTPost Stumpy Old Fart,Deadman Walking, Snow Monkey Moderator

    AlaskaChick & I use about that amount of water (300 USG) in a week, during the winter... We pump from our Insulated Collection Totes into our Cistern, inside our Heated, Insulated, WellHouse, using power from the 20Kw Disel GenSets, that run about 10 Hours a Day...(7 Am-Noon & 5Pm- 10Pm). The Trasfer Pump is a 1/2 HP 120Vac Impeller Pump, We also charge the two Inverter Battery Banks, keep the Freezers cold, & run the Clothes Dryer, during those same 10 Hours a day... Our Cabin Domestic Water System is fed from the Cistern, thru a 12Vdc Stinky Dankof Vane Pump. Thru a Check Valve, and a 30USG 60 PIS Air Bladder Tank. Then thru the 2 Micron Filter, an Activated Charcoal Filter, a 12Vdc UV Irradiation Sterialization Chamber, and the into the Cabin Water System. The Vane Pump & IR Tank run from an 8D Battery charged thru a 12Vdc Constant Voltage Battery Charger, that runs whenever the GenSets run. This Battery also supplies the 12Vdc Emergency Lighting System in the Cabin, whichever was installed back in the early 60s.... We use it for NiteLights...
    T. Riley likes this.
  10. oil pan 4

    oil pan 4 Monkey+++

    An surflo RV diaphragm pump is how I would off grid running water.
    The most common voltage is 12v.
  11. arleigh

    arleigh Goophy monkey

    This might not be your cup of tea but I put my water tank up high and gravity fed the house.
    I built a shop at a higher elevation from the house and put the water tanks up in the loft . no serious pressure is required so less energy is required.
  12. Altoidfishfins

    Altoidfishfins Monkey+++ Site Supporter+

    I use a Grundfos solar well pump. It can run on any voltage from 90-250 VAC, or from 30 to 300 VDC. I connect it directly to ten solar panels in series (through a solid state relay connected to a float switch to control the pump) and use no batteries or inverters. In a pinch, it can be run from a generator.
    Last edited: Jul 25, 2016
    Cruisin Sloth likes this.
  13. Cruisin Sloth

    Cruisin Sloth Special & Slow

    Good setup , but you are pumping water to a holding tank or cistern correct ? this poster I believe is trying to use his deep well pump to pump & pressurize the system , so far If im taking what he posted as 9.6 amps ac @ 230Vac he needs 2500 watts to maintain that load and the start surge on normal DWP's would take a 10KW unit so no damage would be done , batterys to feed that load is huge .

    math is 9.6 amp X 230Vac = watts X time run = watt hours X( % of losses ) that id didn't include
  14. T. Riley

    T. Riley Monkey+++

    I see that is going to be too expensive going the way I proposed. Thinking now a 300-500 gallon storage tank and filling it as needed using the propane generator and then using a Surflo12 volt RV pump to supply the house plumbing. All I would have to buy is the holding tank. I have the 12 volt pump. Does that sound like a doable option? I only use the propane for an on demand water heater and cook stove. I have enough solar for lighting and battery charging with power to spare for the 12v pump.
  15. Altoidfishfins

    Altoidfishfins Monkey+++ Site Supporter+

    WOW! That setup really sucks the power.

    For right now I'm using a holding tank and an RV pump to push the water to a travel trailer. But believe I could run it straight into a pressure tank (or two in parallel for more capacity) and control it with a pressure switch, eliminating the need for the RV pump. The well head has a pressure pop off that releases at 75 lbs. I've forgotten to open the valve while running the well pump and it blows water out of the pop off within 2 or 3 seconds. So I think it probably has enough oomph to pressurize a tank to 50 lbs or so (for a very usable 50/30 pressure range). My pump is set at 580 feet.
  16. oil pan 4

    oil pan 4 Monkey+++

    That is exactly how I would do off grid running water.
    Use a well pump, tanker truck, trailer tanker and/or rain collection to fill a cistern or tank and use 1 or more 12v surflo or the like type diaphragm pump to pressure the system.
  17. Cruisin Sloth

    Cruisin Sloth Special & Slow

    Much better thinking on trying to use the standard deep well pump , once you follow the math & you should have twice as many watts as what you will have as a load . so 1500watt load needs a 3000w inverter MIN.
    Grundfos solar well pump is going to be a must if you want to do it all on solar , and up the battery voltage to 24Vdc min .
    You still can have all the 12Vdc stuff , but you harvest watts .
    first system is 12vdc & same 8 panels & all the stuff is the same . Im using Midnight charge controller that is 12,24,36,48,72,96 voltage in one unit BUT only 96 amps max & 150 max voltage above batterys !!
    BIAB to finish

    8 --350 watt solar panels (40vdc is VOC ,36vdc 8amps IMP ) in parallel to feed the midnight classic CC
    So 8 X 8amps 64 AMPS max & max voltage would be 40 Vdc, alls safe for the CC at 12Vdc and now watts max harvest would be 350w X8 = 2800 in theory but really 24-2500 is what you might see on the best day .from the panels (Just the panels ,NOT harvesting , just what you might see in real life from these 350W panels , any voltage battery bank)
    SO im picking 2500 as in what these panels can grab as in real watts.
    Best day 64 amps X battery voltage 12Vdc = 768 Watts
    Best day 64 amps X battery voltage 24Vdc = 1536 Watts
    Best day 64 amps X battery voltage 48Vdc = 3072 Watts harvested .
    Smaller wires on higher voltage , less voltage drop etc .
    24-12Vdc converters or 48Vdc-12Vdc converters are out there & I run a few.

    One of my systems use's these panels but in series / parallel setup
    2 series in 4 strings parallel
    MidNite Solar Inc. Renewable Energy System Electrical Components and E-Panels
    last week I was punching out 96amps from one of my classics , and then I when in and touched all low voltage connections just to make sure all was still cool & no HOT connections .
    So my classic is MPPT volts in Ive seen 83 but right now 60Vdc in & 85 amps out at 24Vdc so Im 2312 (27.2X 85amps =Watts) Watts harvested . Battery bank is in float at 27.2Vdc The rest of that 85amps is grid-tied to the other systems on our internal grid system .Main internal grid system is a Midnight/Schneider context XW 10kw unit @ 48vdc .
    I take a few pix of the 24Vdc system , as soon as I put it back together tonight .
    I had a outback inverter not having it's internal fan working.
    I run trace Xantrex also , and the new MidNite Special.

    Edit , All back & working . I ran this lower 3524 OB with the top housing off & did some live power diagnosing . Found a bad temp thermistor ..
    Don't try this if your not expecting a shock !!!

    so two 3500 units in single phase is 7000 Watts & will eat 300 amps to make that & needs those 4/0 five foot cables from the 1400 AH battery NCLIPO.
    Just to put many in perspective .
    Diesel/Gas gensets are a different story , and can be used to work together , on times etc.
    TN Andy & Mr Olsen are some who have this setup .,As I also .


    Last edited: Jul 26, 2016
    T. Riley likes this.
  18. Cruisin Sloth

    Cruisin Sloth Special & Slow

    OK so lets try to do a figure out .
    Seeing you posted a like .
    Depth of your well & what state or country for sun vision etc.

    Were just doing water for now !!! the 230Vac deep well pump can have a second pump above as like my well has .
  19. T. Riley

    T. Riley Monkey+++

    165 feet in East Texas. Bison hand pump set above submerged. Pulling the pump and replacing is not an option for me right now. It is my sole source of water that does not require treatment. 230vac at < 10 amps according to installer, have not tested. This is my present solar intended for lighting, battery charging and running the blower on my fireplace insert in winter. I do have a 10kw whole house propane genset with 800 gallons of propane used only for stove and on-demand water heater.
  20. Cruisin Sloth

    Cruisin Sloth Special & Slow

    165 is better , when I saw fish fins 580 , just WOW on start up surge !!!!!!!!!!!!!!


    I see a 12Vdc TOY system 4 batterys in P are killing all 4 .

    DUMP the inverter , someone is selling 48V 3500 outbacks new for 1200-1500 (can't remember) I have so much on !! fleebay or craigs
    put all 4 in series & use 48V & then your moving up.
    NOW , Sorry , a dream . @ what you posted .

    TX,Texas has / needs AC (for me 4 sure , white polar bear) , get a 48V & then run the system to drive a few Mini splits AC units , LIKE ME !!

    I know , Canada the frozen north !!! , 2day 30c and hot for me , AC on & driven all from solar ..!!
    Mini splits seer 21 @19k were 800 each , & needs 1200watts per .
    do the math on driving 2400 w @ 48V with panels up already . if ya need help , pm me a #
    This the TX house with 12Vdc internal wiring?? Or i have a brain fart (normal 4 me)
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