solar to pump distance of 150ft...??? Help

System
System Posts: 2,511 admin
I am helping a farmer run a 12 vdc 7.0 amp water pump that is 150 ft. from six - 15 wt solar panels (90 wats dc) total amperage produced should be about 7.5...from the panels (90 wts from 12v) . This will be my first solar as well as dc experience. Soon after I am going to try to run my 220vac 4.5 amp well pump at my house with similar equipment.
Question...what kind of issues will I have with the distance of 150 ft. running 12v DC...? Any suggestions or advice.
Greatly appreciated.
I have been doing tons of research and am getting ready to jump in the solar world in a big way, albeit slow, but steady.
Any info or suggestions will be GREATLY appreciated!!!
bassist

Comments

  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    Re: solar to pump distance of 150ft...??? Help

    First question is why are you using so many small panels,, instead of one or 2 larger panels? A 90 watt Sun panel can be had for ~$2.50-3.00/watt retail. I would think the wiring headache, and wiring loses with so many smaller panels would out weight any cost savings.

    My next intuition is that you don't really have enough power. If the pump draws 7 amp, and the max amps from you panels is 7.5 you don't have much headroom,, not to mention that the panels won't put out that 7.5 amp except under absolutely ideal conditions. Just for example, my ~200 watt system should put put out ~16 amps max into 12 volts,,, but it usually puts out around 12.

    Since you really haven't asked a question,, I don't know what else to say. I would suggest that you give us some numbers,,, gpm/gpd, is the 150' a horizontal measurement or vertical,,, etc.


    Tony.

    PS up sizing the pipe in most cases makes pumping water easier by reducing friction loses.
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: solar to pump distance of 150ft...??? Help

    Here is a wire loss calculator for solar panels (you can use the data for pump wire loss too--or simply use other voltage drop calculators on the web).

    The problem with 12 vdc is you need a very heavy gauge wire to keep the voltage drop low... For example, you have almost the same requirement--but 240 VAC--A two volt drop at 240 gives you 238--not a problem. And, you will have 20x as much power available at the pump (because the voltage is 20x higher).

    A two volt drop at 12 volts--gives you 10 volts at the load--not much will work will at that voltage level.

    If you can place the panels/batteries next to the pump--it would be much better.

    Larger diameter piping with no right angle bends is good--but if there is sediment in the water, too large of pipe will allow the sediment to collect (mud in bottom of pipe)... So, there is a minimum recommended velocity of the water to keep the debris suspended.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • System2
    System2 Posts: 6,290 admin
    Re: solar to pump distance of 150ft...??? Help

    Thanks to all
    Icarus...I didnt have to ask a question...you knew where I was going...Moderator, you hit it on the head. I know there is a problem loss in ac over 100'...you gave the the actual number in ac. Thanks to all.
    our second plan might be to dig a trench to the water table UNDER the panels...just feet away. Then pump it 150 feet to the cestern.
    I didnt plan this...it's how he started to set it up before consulting with me...after looking at it, I suggested we'd probably need a plan B.
    About 3 -4 acre field running norht south about 50 yards wide. Cistern is on the norhtern end...panel "decking" is 10' high about 150 feet into middle of field. Cant place system next to systern because of tree...nuts and fruit in close proximity.
    I told him he hadnt planned it well...he agreed but wants to try it this way and modify as needed. I think the modification need is now..!!! hehe
    The number of panels is due to the harbor freight kit and the price. watts per dollar.
    My situation wont be as drastic at home...plan on using an inverter anyway.
    Not sure wich panels I will use at first...considering very similar panels but with the 20yr80% rating...I know HF panels arent that...cant be.
    Any suggestions...would like to slowly take sections of my house off grid slowly but surely.
    Thanks to all again.
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: solar to pump distance of 150ft...??? Help

    If you have grid--stay on grid... You are paying around $0.10 per kWhr... Grid Tied can be $0.20-$0.35 per kWhr (less with rebates and tax credits). Off-Grid, ~$1.00-$2.00 per kWhr...

    So, the first three things we recommend here (broken record time)--is 1. Conserve, 2. Conserve some more, 3. A bit more conservation...

    Get yourself a kill-a-watt meter... The best tool for checking your 120 VAC 15 amp loads for how many kWhrs / day or month each device uses. You will very quickly focus on your top energy users (excluding A/C, electric heat/hot water).

    Basically, it is almost always cheaper to spend money saving power than it is to spend money making power.

    Typically--that is lots of insulation--especially in the roof. I like double pane vinyl windows. Energy Star Appliances. And a high SEER (~18?) A/C compressor... If you need heating, make it a heat pump.

    And, depending on your energy source and pricing--e.g., natural gas vs electric hotwater/heating... Things becoming more common are domestic hot water from a heat pump., a heat recovery ventilator, and such.

    Domestic Solar Hot water should be a good value for $$$/kW of heat collected... But the systems can be complex and need a bit of tweaking/maintenance to keep running well.

    Then Grid Tied Solar PV electricity. Especially if you have 1 year net metering type billing plan available.

    If you are in an area that gets hit badly by hurricanes (frequent/long power outages)--and off-grid capable solar PV system is very nice (assuming your home remains safe during the storms).

    However, instead of an off-grid system--look at a hybrid Grid Tie / Off-Grid system... Normally, it operates as a grid tied inverter (efficient, batteries don't cycle). But when AC mains are lost, the system switches over to become a giant whole house Solar Powered UPS (still not cheap, and you will have battery maintenance).

    In the end, you will find that it is very difficult and not very cost effective to "grow" from a small to whole house solar system.

    Many people will start with a small system as an educational tool (power for their cabin/camping, small building site or shed). Then do the "big" system for the home when they have the knowledge and money available.

    For the most part, you buy the panels/equipment for the load you are going to support. And adding batteries to an existing bank is an issue--typically the new batteries are dragged down to near the end of life date of the existing battery bank.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: solar to pump distance of 150ft...??? Help

    1) your 6 panels are likely pretty cheap things, with a short warranty. Consider a single, larger panel.

    2) 90W of panels, will actually produce about 80% of nameplate power (72W)

    3) it's not the "distance" you pump, but the hight, elevation gain, is what requires real work. depending on how deep the well is, maybe have 2 pumps/PV arrays. #1 pumps to surface storage tank. #2 pumps along distance, and up to the hight of the usage/gravity feed tank. Solar is no good for pressure tanks, as it won't re-pressurize after dark.

    4) expensive copper wire for that long of a run.

    5) you will likely need a "Current Booster" for each pump. (read description)
    http://store.solar-electric.com/7amplincurbo.html
    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 ,

  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    Re: solar to pump distance of 150ft...??? Help

    Just so I'm clear, It sounds like you are pumping water a few feet vertically, but 150' horizontally. If that is the case, it makes it much easier than the other way around. Moving the water the horizontal distance is far easier, and ergo takes way less energy.

    If you are going to use a direct panel operated pump, consider adding a linear current booster, to run the pump on 24vdc. The net result of which is higher volumes, lower wiring loses and possibly longer pump life.http://store.solar-electric.com/7amplincurbo.html

    Place the panels near the water source and you will have minimal line loss. As for the pipe, pipe with the largest diameter pipe you can. (You still haven't suggested what kind of volume you are looking for).

    Tony

    PS As I suggest below,,, Name brand panels,, Evergreens etc can be had for ~$3.50 per watt,,, your harbor freight panels work out to be $4.42/watt. I would never install a Harbor freight panel on a customers job. I just don't think they have a reliable reputation.
  • System2
    System2 Posts: 6,290 admin
    Re: solar to pump distance of 150ft...??? Help

    Thanks again everyone for all the help, advice and info. I couldnt have hoped for this much help. Thank you all very very much.
    It is a shurflo 8000 series 12vdc 7.0 amp 1.6gpm pump. The panels will be 10 ' in the air...over tops of crops. It is then aprox. 150' to the cistern wich the top of is 10' in the air. Water will flow to top of cistern and fall through a filtration system.
    Should mention the initial filter will be a sealed bucket with filtering wrapped around it and on the insdie will be more filtering and the intake.
    He (farmer) is considering my idea of running the pump directly below the panels.
    He states if he takes a backhoe and digs down 3-4 feet, the water tabel comes through. that is how he plans on accessing water for the system. Gettint the water 150' to the cistern then up ten feet might be a challenge also.
    Ive included a rough drawing for your entertainment.
    As for the harbor freight panels...he bought two sets to give him 90 watts...I understand totally the argument of price per watt and the longevity and bleed off of efficiency over time...He spent $400 for the two sets...Im not sure if you can buy a 90watt panel for $400. I did find a web site that has similar panels for similar price...chinese still, but the do mention a 20 year 80% efficiency guarantee.
    http://www.ultimatesolarshop.com/album1_003.htm
    thanks again everyone.
  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: solar to pump distance of 150ft...??? Help

    if he has water table at 3', the crops can get it. Pumping will only evaporate more of it.
    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 ,

  • System2
    System2 Posts: 6,290 admin
    Re: solar to pump distance of 150ft...??? Help

    Thanks to all...Mike the only problem with that is its Louisiana...water table one week might be good...next month not there at all...one month later....we're flooded from a hurricane. Actually the area where he's at is around the corner from where I grew up...Im surprised he'd even want to risk it due to the un-predictability of the water table there. Once again, he did a poor planning and setup process from the beginning...didnt take into account of the power loss over distance, nor the water level situation...at least in my opinion...but what do I know about farming. He basically bought some swampish land on the west bank of New Olreans, cleared it and let it dry. He wants to raise a whole food farm for market. Asking me to help him with solar and elect. How could I refuse...??? Especially right before I build My own. Active research. Whatever the case, Im gonna help him make the best of what he's got, work. Somehow...!!! Live and learn, right?
    This site and all of your input has been nothing but invaluable!!! Always willing to listen and absorb.
    Thanks
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: solar to pump distance of 150ft...??? Help

    How much water does he really need (volume and pressure?).

    A 12v*7a=74 watts is a pretty small pump (1/10 HP)...

    You with a 240 VAC * 4.5 amp = 1,080 watt pump (approaching 1 HP)--at least is in the ball-park for some useful amount of water for a commercial installation (isn't it?).

    Also, big difference between flooded type irrigation vs spray/drip too (higher the pressure, more energy needed to move the water).

    Solar is only cheap if everthing else is expensive (cost to lay in grid power, cost of delivered fuel for gasoline/diesel powered pump, etc.)...

    Also, Solar, to be most cost effective, is best if used some 9 months (or more) of the year. If there is only a 3 month growing/watering season--then the panels sit there doing nothing...

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset