Off-grid 2000w recomendations

Hi, new here
would like recomendations on a off-grid 2000watt system w/generator
for emergency charging.

Comments

  • System2System2 Posts: 6,290 admin
    Re: Off-grid 2000w recomendations

    that would be a 24v system
  • AntronXAntronX Solar Expert Posts: 462 ✭✭
    Re: Off-grid 2000w recomendations
    laldebot wrote: »
    Hi, new here
    would like recomendations on a off-grid 2000watt system w/generator
    for emergency charging.

    Location? Budget? What loads you are powering?

    Best value for money:
    Panels: SUN ES-A-205-fa3 panels at $1.74 per Watt
    charge controller: Morningstar TriStar MPPT
  • System2System2 Posts: 6,290 admin
    Re: Off-grid 2000w recomendations

    baja california, med budget, small LG hi efficient fridge, 4 60watt bulb([email protected]),laptop 3 hrs, 1/3hp well pump.
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Off-grid 2000w recomendations
    laldebot wrote: »
    baja california, med budget, small LG hi efficient fridge, 4 60watt bulb([email protected]),laptop 3 hrs, 1/3hp well pump.

    My 'frige is 'hi effciency'. It uses approximately 1600 Watts per day. I also have a 1/3 HP well pump: 850 Watts running, triple that on start-up (your results may vary: pumps are somewhat unpredictable on current draw) but it only runs about 6 minutes per day (very large pressure tank).
    When you say "4 60 Watt bulbs" I assume you mean incandescent? Replacing with CFL's will cut that from a variable 240 Watt load to a variable 52 Watts (variable due to time of use).
    Laptop is less consuming than any of those other loads. Ours uses about 50 Watts peak. Yours may be different.

    Now I also run a satellite set-up and desktop computer: roughly 200 Watts peak and minimum 25 Watts when just idle. And there's a whopping 1 HP septic pump, but that runs 1 minute per day. Sometimes we use a microwave (1000 Watts). My sig will tell you what system I've got, and it needs more battery and panel to really handle the loads.

    Now as to the cost ... Well, this is BC and everything costs too much here. That set-up, installed myself, was roughly $10,000 - and bought over time as needs grew and money became available.

    Just a little real-world data from someone who's been there, done that. :D
  • BB.BB. Super Moderators, Administrators Posts: 32,016 admin
    Re: Off-grid 2000w recomendations

    You do want to design your system to support your loads... A 2kW system, assuming 5 hours of sun per day (good, weather average over a year) and a derating of 0.52 (end to end system efficiency) would give you a useful daily average power for 120 VAC of:
    • 2,000 watts * 5 hours sun * 0.52 derating = 5,200 Watt*Hours a day (average)
    Assuming you want to plan on 4,000 WH per day, a 24 volt battery bank, 85% efficient inverter, would be sized for (assuming 3 days no sun, 50% max discharge):
    • 4,000 WH * 1/24 volts * 3 days * 1/0.50 * 1/0.85 = 1,176 AH battery at 24 volts
    This is a large system...

    Looking at a genset... What fuel works best for you (diesel, propane, gasoline)?

    And sizing the genset--Especially for diesel, but ideally for most generators, it is best to size them to run (on average) at least at 50% of rated output capacity for long life (diesels) and good fuel economy (all generators).

    Most people tend to get over-sized generators for their systems. In a few cases, it may make sense (to run a shop full of wood/metal working tools). In many cases, all it does is cost the owner 2-4 times as much fuel to charge their battery banks.

    Lets assume your batteries will be charged between 5% and 13% of AH capacity. Run the genset at 50% of capacity, 24 volt bank (29 volts charging) and the battery charger is 80% efficient. The Generator Rating and Battery Charger output current min/max would be:
    • 1,176 AH * 0.05 * 29 volts * 1/0.80 chrg eff * 1/0.50 gen load = 4,263 watts minimum generator
    • 1,176 AH * 0.05 = 59 amps recommended minimum battery charger minimum
    • 1,176 AH * 0.13 * 29 volts * 1/0.80 chrg eff * 1/0.50 gen load =11,084 watts maximum generator
    • 1,176 AH * 0.13 = 153 amps recommended maximum battery charger minimum
    Please note, all of the above is just wild guesses on my part. Knowing more about your loads and needs, and how much sun you get locally (coastal/marine layer, or more desert), etc. will change the above assumptions.

    Also, these are just rough rules of thumbs to quickly size a system. You may want more solar panels or less batteries.... You may use more power in the winter vs summer (or the oposite). May only be occupied on summer weekends, etc...

    Just a starting point for discussions.

    For pricing, you can start with our host Northern Arizona Wind & Sun webstore--in Flagstaff Arizona--So I am sure they can help you with any Baja related questions too.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • System2System2 Posts: 6,290 admin
    Re: Off-grid 2000w recomendations

    i'm only there 6 weeks a year
  • BB.BB. Super Moderators, Administrators Posts: 32,016 admin
    Re: Off-grid 2000w recomendations

    If you are there only 6 weeks a year, look at minimizing your electrical loads... Such as a propane fridge...

    Build a small battery + generator system to handle your evening loads--and for large loads during the day, plan on using the genset. You can install as much or as little solar panels as you want (start small to maintain the batteries during off season).

    Solar Panels make economic sense when you are using their power for 9 months of the year... For use 1.5 months of the year--the rest of the year, the panels will generate power you will never use. High Capital costs without any return.

    A genset is relatively cheap and only costs your fuel when you need the power.

    A 2kW set of panels + batteries is difficult to justify (unless you are renting the space out for the rest of the year).

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