Dominica post Hurricane Maria

In_the_darkIn_the_dark Registered Users Posts: 1
I am trying to learn this subject but feel I could use some advice.
Currently I am in London shopping for rebuilding materials to ship to Dominica. At the time I write only 3.6% of the island is connected to the grid. We expect to be without power for up to two years.
Could anyone suggest a shopping list for a solar panel system capable up providing sufficient power for a fridge, microwave, lighting and power tools.
We are on a latitude of 15 degrees.
Thanks

Comments

  • mike95490mike95490 Solar Expert Posts: 7,284 ✭✭✭✭
    First is to buy an efficient Fridge, instead of installing 2x the solar array
    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 ,

  • jonrjonr Solar Expert Posts: 858 ✭✭✭✭
    You might run a generator for a day or two and measure your average kWh/day usage. In a hot climate, consider lithium batteries (probably too early) or lead acid batteries that are actively cooled. Propane is the cheapest generator fuel?
  • 706jim706jim Solar Expert Posts: 168 ✭✭✭
    1500 + watts of panels and batteries to match
    Island cottage solar system with 1400 watts of panels, Trace DR1524 MSW inverter, Trace C40 PWM controller 8 Trojan L16's. My 24th year.
  • bill von novakbill von novak Solar Expert Posts: 706 ✭✭✭✭
    edited November 13 #5
    I am trying to learn this subject but feel I could use some advice.
    Currently I am in London shopping for rebuilding materials to ship to Dominica. At the time I write only 3.6% of the island is connected to the grid. We expect to be without power for up to two years.
    Could anyone suggest a shopping list for a solar panel system capable up providing sufficient power for a fridge, microwave, lighting and power tools.
    We are on a latitude of 15 degrees.
    Thanks
    Let's make a wild guess of 10kwhr/day (less than half US average, assumes very efficient fridge.)  That's a 30-40kwhr battery with a ~4kW inverter.  You'd need about 3kw worth of solar panels to charge that.  Go for 48V; it will be easier overall.

    Choose battery types.  Do you want cheap and short-lived (a few years) or more expensive but lasting 10-20 years?  Maybe cheap is the way to go since you don't anticipate this lasting forever.  There are lots of options out there now.

    Make sure you get a hybrid inverter capable of doing grid tie, so when the power comes back you can still get benefit out of the system.
  • westbranchwestbranch Solar Expert Posts: 4,860 ✭✭✭✭
    We do quite satisfactorily on 1680W of panels  and a 1500W inverter in the summer, in fact I can run the following at the same time:  fridge and lights , battery powered -  drills & impact screw drivers plus an induction cook top (just - if power level kept low); but not the power skill saw, nor Microwave.    This is using a 24V system...

    My suggestion would be go for a:
     good  2000W PURE SINE WAVE  Inverter,
     ~ 1500W of panels,
    a MidNite Solar Classic MPPT Charge Controller or one similar capacity and quality,
    a 24Volt  battery of 2 x ( 4 - 6 volt cells) Golf Cart battery,
    if needed this can be reconfigured into a 48 V setup but would need a different Inverter, the Classic CC  will do either voltage, no problem.

    The biggest issue , all the time is having 2 or more large loads that turn on at the same time, that is when you need a bigger capacity Inverter

     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge, Hughes1100 Sat Modem
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
  • mcgivormcgivor Registered Users Posts: 1,280 ✭✭✭✭
    The idea of a hybrid system as @bill von novak mentioned  is a good suggestion, an inverter charger is a cost effective way to go, it allows future grid support , generator support and battery backup during outages. When the cost of purchasing all separate components is considered, a good inverter and battery charger, the cost is almost the same. With the inverter charger, it is a "system which is designed to work together, wether it can feed into the grid or not, in the future, depens on local regulation. The future  grid reliability will probably be questionable after such extensive damage, for some time after restoration.
      1500W, 6× Schutten 250W Poly panels , Schneider 150 60 CC, Schneider SW 2524 inverter, 8×T105 GC 24V nominal 

  • BB.BB. Super Moderators Posts: 26,837 admin
    I suggest that you may wish to build a minimum size system. A 3.3 kWH per day (3,300 Watt*Hour) per day system should be enough to run an Energy Star refrigerator, LED lighting, a small/efficient well pump, washing machine a couple times a week, LED TV, and a laptop/cellphone charger. Such a system may look like:
    • 3,300 WH per day * 1/0.85 AC inverter eff * 2 days storage * 1/0.50 maximum discharge * 1/24 volts = 647 AH @ 24 volt flooded cell lead acid battery bank
    Charging the battery with solar--Two calculation. First 5% to 13% rate of charge. 5% for weekend/seasonal system. 10%+ is better for full time off grid systems:
    • 647 AH * 29.0 volts * 1/0.77 panel+controller derating * 0.05 rate of charge = 1,218 Watt array minimum
    • 647 AH * 29.0 volts * 1/0.77 panel+controller derating * 0.10 rate of charge = 2,437 Watt array nominal
    • 647 AH * 29.0 volts * 1/0.77 panel+controller derating * 0.13 rate of charge = 3,168 Watt array typical "cost effective" maximum
    And there is the amount of array you need by hours of sun per day by month. Assuming fixed array and random city in Dominica:
    http://www.solarelectricityhandbook.com/solar-irradiance.html


    Berekua
    Average Solar Insolation figures

    Measured in kWh/m2/day - panels set at an angle of 75° for best year round performance.
    Jan Feb Mar Apr May Jun
    6.68
     
    6.94
     
    6.99
     
    6.44
     
    6.55
     
    6.60
     
    Jul Aug Sep Oct Nov Dec
    6.55
     
    5.95
     
    6.16
     
    6.39
     
    6.31
     
    6.55
     
    Nice amount of sun (on average):
    • 3,300 WH per day * 1/0.52 AC system off grid eff * 1/5.95 hours of sun (August minimum) = 1,067 Watt array minimum
    I would suggest 2,437 watt as being a nice size array, plus it does give you more power during daytime (tools, washer, computer, etc.)... Such an array would supply (on an average August day):
    • 2,437 Watt array * 0.52 off grid AC system eff * 5.95 hours of sun per day (Aug) = 7,540 WH per avg sunny day
    A lot of "excess power" that you can "burn up" during the day (more loads, power tools, water pumping, etc.).

    The minimum AC inverter should be (typically) a minimum of 1,200 to 1,500 Watts (typically the refrigerator is the worst case load--Although, if you have a well pump, that could be much higher surge current).

    The basic scaling of the system--If you want 9.9 kWH per day--Take the above and multiply by 3x. If you want 1 kWH per day, divide by 3.3 will give you equivalent battery bank and solar array sizing (with my above guesstimates of your needs).

    Note that the battery bank voltage--If battery bank AH rating is >~800 AH, to go the next higher voltage is suggested (i.e. 800 AH @ 24 volts vs 400 AH @ 48 volts)--The two example battery banks, are the same "size" in terms of energy storage--Just reconfigured series/parallel cells and/or different size (AH and Voltage) batteries to make up banks.

    The nominal 24 volt AC inverter would be in the ~2,400 Watt range, and ~3,250 Watt maximum for that size battery bank. Too large of AC inverter wastes energy (larger inverters take more energy just to turn on) and the battery bank will be quickly discharged if run at high rate of discharge. Smaller AC inverters use less wattage to "turn on" and stress the battery bank less.

    The above is a suggested starting point. How does it look for you (costs, size to ship, capabilities, etc.)?

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • jonrjonr Solar Expert Posts: 858 ✭✭✭✭
    edited November 14 #9
    At $.39+/kWh, I'd avoid ever making much use of the grid. Ie select your system and loads for continued use even after two years. Evidently net metering is an option, although in general I'm skeptical about utilities continuing to pay attractive rates.

    Maybe an OutBack FXR series inverter?
  • BB.BB. Super Moderators Posts: 26,837 admin
    "Golf Cart" batteries in warm weather tend to last ~3-5 years even if you take good care of them.

    What you do after the batteries wear/age out... It depends on how reliable your power grid is/will be. In many regions, it is not uncommon for folks to lose power in the afternoons for ~4+ hours per random day... You can keep the system up and running, and use a "fail over" relay (or nice inverter or inverter/charger) to automatically switch over to battery backed power during utility failures.

    Many times, you can use the grid as a "backup genset" to recharge at night/morning (especially during bad weather) if you have semi-reliable AC power (with or without solar panels--Typical Caribbean home backup up power installation).

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