How to install Solar Panal for 24 Fuel Pumps for 20hrs daily

Details from anyone


  • VeichiElectricVeichiElectric Posts: 2Registered Users
    u really should read this article about solar pumps:
    In your case I wonder if a solar PV inverter would help or not.

  • BB.BB. Posts: 27,882Super Moderators, Administrators admin
    Can you tell us more about the pump? For example, what is the average current?

    We need Amps * Hours of use, how many days of use in bad weather (sizing of battery bank), and where the system will be installed (hours of sun per day), seasonal usage (lots of sun in summer, not so much in winter).

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • JohnnyJohnny Posts: 8Registered Users ✭✭
    Yea Bill, Pumps is normal 750va Petrol Pump each. Here we have Sun up to 8-10 hours daily. Our weather is usually hot and dry. Not much of Bad weather, there is almost daily Sun here, quite hot and Dry. Usage is expected to run 24hous daily would just last for maximum of 18hours bad weather, maybe once or twice a week. Its completely off Grid. Battery Size is 200Ah each. Please kindly advice
  • JohnnyJohnny Posts: 8Registered Users ✭✭
    Veichi, please did you really understood my question? Kindly look at it again. Thanks
  • BB.BB. Posts: 27,882Super Moderators, Administrators admin
    edited May 2016 #6
    Is this a retail petrol fueling station? With 24x pumps used 20 hours per day each?

    Or, on average, do you run 4-5 pumps x 20 hours per day average? 230 vac @ 50 Hz?

    Are you near Port Harcourt Nigeria?

    How are you running now? Gensets?

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • KeithWHareKeithWHare Posts: 140Solar Expert ✭✭✭
    Johnny, some additional information would be:
    • How many pumps? One per installation or multiple per installation?
    • What percentage of the time is each pump actually pumping?
    • What voltage are the pumps?
    • What is the surge when a pump starts pumping?
    • What's the voltage on the 200Ah

  • JohnnyJohnny Posts: 8Registered Users ✭✭
    Yea its a Retail Petrol Fueling Station. Each Pump Runs for 18hours daily. The Pumps only stops working when a Full-Tank vehicle leaves for the Next Vehicle behind to move closer to the Pump. Like I said, we are running on 230VAC. No am not near PortHoarcourt-Nigeria. Yes for now we are runing on Genset but we want to change to Solar System.
  • JohnnyJohnny Posts: 8Registered Users ✭✭
    # Keith,

    I said I have 24 Fuel Pumps, its multiple installation (Two pumps in one Stand)
    Each Pump runs for 18hours per day. (Our Petrol Station runs for 24hours)
    Each Pump is 750A
    When a Pump Starts, its surge goes upto +_ 10A
    Am running 0n 220VAC

    Thanks Keith
  • BB.BB. Posts: 27,882Super Moderators, Administrators admin

    Where (roughly) is (are) the pumps (figure out "hours of sun" per day)? For example, we will use a website like this to figure out available sun (by season):

    Is this one installation, or 12/24x separate locations--Each retail location with 2 pair of pump motors?


    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • JohnnyJohnny Posts: 8Registered Users ✭✭

    We have 8hours Sun daily. In extreme bad weather, it could drop to 5hours, but thats maximally once week
  • BB.BB. Posts: 27,882Super Moderators, Administrators admin

    Can you pick a country+city from the list here?

    Very few locations have much more than 7 hours per day of sun with a fixed solar array...

    And do you need 1x big system or 12-24 separate systems?

    With your existing installation, do you have any direct measurements of Watt*Hours per day or kWH per day (or month) for "the station"?


    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • JohnnyJohnny Posts: 8Registered Users ✭✭
    # Bill,

    Thanks for your time. All you are asking have been answered previosly. Please kindly look upwards you will see. In my City we have upto 8hours Sun. Some places have upto 12hours. Thanks
  • BB.BB. Posts: 27,882Super Moderators, Administrators admin

    We are having a bit of a miss-communications going on here...

    First, "hours of sun" in our (engineering terms) is not how many hours per day the sun shines on the panels--But instead based on equivalent hours of 1,000 Watt*Hours per sq meter of full noon time sun.

    So, you may have (for example) 10 hours of sun shining on the panel, but when you add up all of the energy actually collected (sun is only 90 degrees to panel at noon/12:00, the rest of the time the sun is at an angle to fixed solar panels and morning/evening, the sun is going through more atmosphere (distance sun travels through earth's atmosphere is longer, therefore less intense light).

    We use charts built up from local weather measurements and/or satellite estimates on amount of energy per day, variations due to weather, and even how you tilt the panels (mounted flat, tilted 45 degrees, etc.), elevation, humidity, dust/clouds, etc. You can even adjust the panels 2-4 times per year (more flat in summer, more tilt in winter), to collect more energy (or you can use full tracking panels too).

    If you cannot tell me where the system is installed--You can just cut and past the chart in your post without the city name:

    Average Solar Insolation figures

    Measured in kWh/m2/day -  set at an angle of 79° from vertical for best year round performance.

    Jan Feb Mar Apr May Jun
    Jul Aug Sep Oct Nov Dec
    Also, I still did not understand if this is one big system or 12 separate systems (different locations around the country).

    What is the average Watt (or kWatt, kVA, etc.) reading(s) from the genset?


    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • JohnnyJohnny Posts: 8Registered Users ✭✭


    Ok I think I now understand what you mean.

    Firstly, highest intense Sun light is 4hours per day.

    Then we are trying to acquire full tracking panels.

    Thirdly there is nothing am hiding my dear. You asked if I were in Port Harcourt, no, am in Enugu and i deal on Solar. So the installation is not done yet but it would be done here in Nigeria, in two Cities of Enugu and Kano. Kano has more intense Sun than Enugu.

    I can see you mentioned Zaria, are you in Nigeria? 

    Don’t you think that setting a Panel at an angle of 79° from vertical may actually not be applicable to all locations, especially with the two cities I mentioned, Enugu and Kano?

    Yes this is one big System, am working on a Load of 28000watts

    Hope these answered your questions



  • BB.BB. Posts: 27,882Super Moderators, Administrators admin
    Good Day Johnny,

    OK, just trying to work with the best information on your needs/location. I understand that sometimes there is security and/or commercial contracts involved and putting details of "bids" on an open forum is not always a good thing.

    Personally, I am just south of San Francisco California. I was guessing Port Harcourt based on your IP Address and Geobytes. I am a "Moderator" on the forum (and I can "see" your IP Address) and I use this to estimate (guess) where folks are located so that I/we can give best answers to your needs.

    Regarding panel tilt... Angle is based on location and power needs... If you are looking for 1 or 2 axis tracking--That could help you some--But you will have to look at the economics of a tracking system (tracking mounts, motors, maintenance). Tracking can be a big help closer to the poles of the earth, for for those near the equator, may not be as much. For off grid systems, we talk about installing "virtual trackers"--Face 1/2 of your arrays east and others west. This gives you a longer "window" of high(er) charging current for your battery bank vs possible lower installation/maintenance costs (tracking mounts are not usually "cheap", where extra solar power are not that expensive).

    As you know, solar power is not cheap--And trying to both figure out how to conserve energy usage (efficient pumps, lighting, computer usage, turn stuff off when not used) and having accurate load measurements helps to design a system that will best meet your needs.

    Next post will be with the math (too big for one post).

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • BB.BB. Posts: 27,882Super Moderators, Administrators admin
    The following is a "rules of thumb" (or "rules of thumbs") first pass at what, I think, you are asking about. Here is my work. Assuming 28,000 Watts peak load, and say (worst case) 750 Watts (Volts*Amp is >= Watts) * 24 pumps * 18 hours per day, 48 volt battery bank (unless you can get higher voltage inverters+chargers), and you want a minimum of 10% charging current to batteries (~13% maximum "typical cost effective" for solar charging). For Lead Acid Batteries, 2 days of storage (1-3 is typical) and 50% maximum discharge (for longer battery life). This will be for Enugu Nigeria.

    First, the battery bank. Typical "off grid home" assumes charging during the day and discharging at night (and/or bad weather). For your installation, you will be using power both day/not daytime, and during bad weather. So, a typical 48 volt system would look like:
    • 750 "Watts" * 24 pumps * 1/0.85 AC inverter eff * 18 hours per day = 324,000 Watt*Hours per day
    • 324,000 WH per day * 1/0.85 inverter eff * 2 days * 1/0.50 max discharge * 1/48 volt battery bank = 31,764 AH @ 48 volt battery bank
    Note: While I will continue the math/design--More than likely such a large system may do better (and safer) if divided up into multiple smaller systems--Worry about that in later posts once you have the "basic needs" designed.

    Now, charging current. Nominally, the batteries need a 10%-13% charging current (lead acid deep cycle/industrial flooded cell). In your case, you also have loads on the system during the day--So, the solar array should supply both charging current and daytime loads. This may "over size" your solar array trying to give your batteries a "long life" (makes initial install more expensive vs longer battery life).
    • 31,764 AH batter bank * 59 volts charging * 1/0.77 panel+controller derating * 0.10 rate of charge = 243,386 array "nominal"
    • 31,764 AH batter bank * 59 volts charging * 1/0.77 panel+controller derating * 0.13 rate of charge = 316,402 array "cost effective maximum"
    • 750 "Watt" load * 24 pumps * 1/0.77 panel+controller derating * 1/0.85 inverter eff = 27,502 Watt array added to above to support pumps running during daytime
    Then there is sizing the array based on "hours of sun" per day. For a fixed array in Enugu:

    Average Solar Insolation figures

    Measured in kWh/m2/day onto a solar panel set at a 84° angle from vertical:
    (For best year-round performance)
    Jan Feb Mar Apr May Jun
    Jul Aug Sep Oct Nov Dec
    Note, if you have different Winter vs Summer loading (say more loads in summer, then 99 degree from vertical, pointing north, may be a better fixed tilt).
    • 324,000 Watt*Hours * 0.52 off grid system eff * 1/4.0 hours of sun per day (little backup genset support) = 155,769 Watt array minimum
    If you use a full 2 axis tracking array:
    MonthSolar Radiation
    ( kWh / m2 / day )
    Or if you go fixed array (80 degree from vertical, facing south):
    MonthSolar Radiation
    ( kWh / m2 / day )

    If you use July for this second calculator, the July increase is roughly 29% more power from 2 axis tracker vs fixed array--So that gives you a rough idea of how much sizing difference there would be--And you can look at the increased costs from mechanical tracking vs fixed array, and see is worth it.

    For a fixed array, I would suggest that you look at minimum tilt of ~85 degrees from vertical so that panels are somewhat self cleaning (rain washes off dust).

    So--That is where I would start. The above is probably over sized by, at least, 20-30% due to secondary issues. Typically and electric motor runs at a PV of ~70-80%, so that VA*0.7=Watts would reduce electrical loads. Also, during "typical" sunny days, you don't have the ~20% losses of cycling the batery bank (array is powering pumps while sun is ~9:00 to 15:00). But, we have not accounted for lighting, power for billing computer(s), possible fan/Air Conditioning, etc.

    It would probably make sense to design+build a ~1,000 AH battery bank+10,000 Watt array and connect it to 2-4 pumps and see how the system works out--Then build it out once you have better information.

    I would also look at alternative solutions (look for more efficient pump motors/controllers) and simply using solar to reduce genset fuel usage (i.e., solar to support 60-80% of loads). Or even a "hybrid" generator system. Genset to support "peak loading" and use inverter+battery bank to support off peak (possibly early morning/late evening loads)--Genset runs during peak time+recharges battery bank--And add solar panels as needed to reduce genset run time overall.

    Your thoughts?

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