Could anyone see my offgrid system sketch

konstantin.neo
konstantin.neo Registered Users Posts: 19
I am trying to draft up an off-grid system for medium size house of 3 people. I have a GE fridge with a label on the side that reads 485Kwh of yearly consumption, I have a desktop computer that uses about 350W which I plan to use maybe 2.5 hour a day, a 75w laptop that could be used more often than the desktop for browsing, some lightning at night, tv.
I am located in Mexico and I have this dealer named ERDM-Solar which manufacturers PV panels in mexico and also deals Wiosun (german/austria) PV panels.

So far this is the list of products I have choosen:

Solar Panels Wiosun C235P (in strings of 2 by 2)
Charge Controller OUTBACK FLEXMAX 60
ROLLS S-530 Serie 4000 (8 batteries wired 2 series 4 parallel)
Inverter OUTBACK FX 2524 T
OUTBACK MATE 2

Would this setup allow for batteries to recharge during the day or I need to add more PV panels?

Please advice.
Thank you.

Comments

  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: Could anyone see my offgrid system sketch

    I don't see a sketch attached

    Input your data into PV watts http://www.nrel.gov/rredc/pvwatts/ for your location and panel setup, and if in the shortest months, you can harvest 2x your daily consumption, you are good.

    Mesure all your loads in WATT HOURS. 80 watts for 3 hours = 240 watt hours
    Measure your harvest in watt hours 600W of PV for 4 hours = 2400wh.
    All losses generally add up to 50%, so if your harvest is 2x your load, OK. If less, you need to run generator. You need a generator for bad weather too
    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 ,

  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: Could anyone see my offgrid system sketch

    Do yourself a big favour and buy a Kill-A-Watt meter before you buy anything else. The power consumption ratings on appliances and computers are notoriously inaccurate. Sometimes they use more, sometimes less. Running them through the K-A-W for a few days (at least - refrigerator consumption varies with the season) will give you much more accurate expected loads, and that is key to creating a viable system.

    From there you will know your maximum load, which will dictate the inverter size, and your daily Watt hour consumption, which will dictate the size of the battery bank.

    Of that, you propose four parallel battery strings. This is not a good idea. It is better to use higher Amp hour batteries in series and/or increase the system Voltage if you need that much storage capacity.
    Rolls-Surrette S530 batteries are 6 Volt 400 Amp hour, to my knowledge. You would need four in series to get 24 Volts. With eight total, you'd have two strings of four resulting in 24 Volts and 800 Amp hours. That would be up to 9 kW hours of capacity, which is large for an off-grid application. You would also need around 2.5 kW of PV array, and the FM60 would not be sufficient for the current. Furthermore, Surrette batteries have had some serious problems of late. I personally don't recommend them anymore. Feel free to disagree.

    Outback equipment on the other hand is very dependable. But you need to accurately evaluate your loads first, then pick the batteries & inverter, then size the array for recharging the batteries.

    For what it's worth, I run about 2.4 kW loads hours per day off-grid including 'frige and computer (go for laptop if you can; they consume far less power for the same use) using a 24 Volt system. It has 320 Amp hours of battery and 700 Watts of PV. Ideally I would increase both the battery and PV as it is a bit marginal at times.
  • remtzi
    remtzi Registered Users Posts: 3
    Re: Could anyone see my offgrid system sketch

    You can write the reading of your power meter, turn on all the devices you want, wait for 1 hour and write the new reading of the power meter.
    Calculate the consumed power. I made the same calculation in my home- 1 deskop computer + 2 TVs + 1 fridge + 4 CFL lamps consumed 600W for 1 hour.


    Regards.
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: Could anyone see my offgrid system sketch

    Yes, you can... In fact do it for 24 hours and get the daily estimated load.

    Also, most meters (mechanical dial, and LCD Bar) have a rotating disk (or flashing bar) that you can time... Say it takes 30 seconds for one "rotation", you then divide that into time and multiply by a conversion factor for your meter.

    Take the Kh number on the face of the meter and:
    • Kh * 3,600 sec/hour / (# of seconds for 1 revolution of meter "dial") = watts
    (Kh is the watt*hours per revolution)

    Example with Kh=12 WH/Rev and Time = 28 seconds per revolution
    • 12 wh/rev * 3,600 sec/hour / 28 second per 1 revolution = 1,543 Watts
    Your "Kh" number may be 12 or it may be some other number.

    At least this way, you can estimate your power usage in a few minutes or less.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • bmet
    bmet Solar Expert Posts: 630 ✭✭
    Re: Could anyone see my offgrid system sketch

    B.B.

    Thank you for that breakdown on the meter math. I put one on my new(to me) RV to isolate it from Ranch use. I have 1800 W of 24V panels that I would like to power the RV with, and this should help me to figure out if its possible.

    BB. wrote: »
    Yes, you can... In fact do it for 24 hours and get the daily estimated load.

    Also, most meters (mechanical dial, and LCD Bar) have a rotating disk (or flashing bar) that you can time... Say it takes 30 seconds for one "rotation", you then divide that into time and multiply by a conversion factor for your meter.

    Take the Kh number on the face of the meter and:
    • Kh * 3,600 sec/hour / (# of seconds for 1 revolution of meter "dial") = watts
    (Kh is the watt*hours per revolution)

    Example with Kh=12 WH/Rev and Time = 28 seconds per revolution
    • 12 wh/rev * 3,600 sec/hour / 28 second per 1 revolution = 1,543 Watts
    Your "Kh" number may be 12 or it may be some other number.

    At least this way, you can estimate your power usage in a few minutes or less.

    -Bill