solar generator

System
System Posts: 2,511 admin
in General Solar Power Topics #1
I am trying to plan for a diaster. gasoline generator wont be worth nothing after a couple of weeks if we have no gas. so far a long time disaster would i get a solar one so i can run a window ac unit my well and ice box. please help me.astromom2005@aol.com
· Share on Twitter

Comments

  • System2
    System2 Posts: 6,290 admin
    #2
    Re: Small A/C problems with off-grid solar
    CVN-71 wrote: »
    Last week during the "heat wave", we lost power here at the house, on two days. I used my off grid 24v battery bank to run the a/c, and two refers, plus aquarium. Fortunately it was during peak sun and the batteries did not get depleted much, at 7pm I was still at 90%. My system didn't have problems running the 600w a/c on low and 2 fridges. I'm assuming my 4000w inverter was powerful enough to do the job. Boy was i glad I had this set up. I simply can't run a generator and then go to work leaving it unattended.

    help me i want to see about getting a solar generator.i am wanting it for a long disaster.like months to run my well and ac unit and refrig. what do you think and what size?
    · Share on Twitter
  • ssun
    ssun Registered Users Posts: 5 ✭
    #3
    Re: Small A/C problems with off-grid solar

    astromom,

    You're going to need to know what your load is, specifically what current (and at what voltage) is required and the duty cycle (how long it is actually on every day). If you're interested in a report I wrote up for my own needs, PM me your e-addy and I can send it to you.

    ~Dan
    · Share on Twitter
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #4
    Re: solar generator

    I've consolidated these posts under one thread to try and keep it organized.

    Like Dan said, you need to know your loads: how many Watts and how many Watt hours per day.

    In short form I can tell you that refrigeration equipment, including air conditioners, generally have big start-up demands and use quite a bit of energy per day. In terms of back-up power, solar is a pretty poor value. This could be a lot of expense for very little "insurance".

    There are many threads on the forum dealing with this; I search about when I have time and add some links.
    · Share on Twitter
  • arkieoscar
    arkieoscar Solar Expert Posts: 101 ✭✭
    #5
    Re: solar generator

    Easily and quickly done. Just budget between $25K-$30K. That's cheaper than it would have been a couple of years ago and the equipment it better too.
    · Share on Twitter
  • deacon
    deacon Solar Expert Posts: 33 ✭
    #6
    Re: solar generator

    I built a system to do what you are seeking to do. It runs, 3 A/C units during daylight hrs along with 2 refrigerators and a freezer 24X7, also runs my TV, Sat dish, computers, ceiling fans, bla bla bla. Total cost for the off grid system was about $22K. The batteries were $6K alone. I hope to recover some cost with the federal and state tax incentives.
    Off grid is not a cheap way to go.
    The same system but Grid-Tied would have been about $12K.
    Here's why.
    Progress Energy would have paid for $4K of it. It is a 5.3 KW system but they would rate it @ 4KW. They provide a check for $1000.00 per KW for your system.
    Then I would have saved $6000.00 in Batteries.
    That is not what I wanted. I wanted Off-Grid so It cost me.
    · Share on Twitter
  • Vic
    Vic Solar Expert Posts: 3,208 ✭✭✭✭
    #7
    Re: solar generator

    As has been noted here in a number of threads, a generator with a large enough fuel supply, integrated with some batteries and some solar can be an effective solution to this need.

    As posted above, to do this only with solar, batteries and an inverter can be very expensive. But this system would be "nicer", generator run-time could be minimized with this approach.

    The inverter-generators are quiet, fuel-efficient, and can handle fairly large motor start loads, for their size.

    Vic
    Off Grid - Two systems -- 4 SW+ 5548 Inverters, Surrette 4KS25 1280 AH X2@48V, 11.1 KW STC PV, 4X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  25 KVA Polyphase Kubota diesel,  Honda Eu6500isa,  Eu3000is-es, Eu2000,  Eu1000 gensets.  Thanks Wind-Sun for this great Forum.
    · Share on Twitter
  • ggunn
    ggunn Solar Expert Posts: 1,973 ✭✭✭
    #8
    Re: solar generator
    astromom wrote: »
    I am trying to plan for a diaster. gasoline generator wont be worth nothing after a couple of weeks if we have no gas. so far a long time disaster would i get a solar one so i can run a window ac unit my well and ice box. please help me.astromom2005@aol.com
    Basically, what you want is battery backup. In a battery backup with solar, the only role of the solar is to charge the batteries; you cannot run from solar alone when the grid is down.
    · Share on Twitter
  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #9
    Re: solar generator
    ggunn wrote: »
    Basically, what you want is battery backup. In a battery backup with solar, the only role of the solar is to charge the batteries; you cannot run from solar alone when the grid is down.
    Had to read "ggunn"'s answer twice to make sure--But read it closely, for solar panels, most applications need a battery bank to buffer the power from the panels (variable, daytime only) to loads (fixed power requirements, 24x7 need). And batteries are expensive and have limited life (very dependent on application, batteries purchased, etc...

    However there is one solar PV only application that does work out nicely... That is pumping water from a well. There are setups where the pump only pumps as much water as there is solar power available (Grundfos and a few others), and fans that use a linear current booster to optimize air movement when not middle of the day (motors need lots of current but not too much voltage to get moving--LCB's convert high voltage/low current from arrays not under full sun to low voltage/high current to get the motor running under cloudy weather, etc.).

    Obviously, does not address a refrigerator and A/C, but battery-less solar has been done for swamp coolers, a couple (expensive) off-grid refrigerators (typically used for medication storage and such), and well pumping.

    Does not make for a "comfortable" off grid home, but could be the difference between life and no-life for many people.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
    · Share on Twitter
  • techntrek
    techntrek Solar Expert Posts: 1,372 ✭✭✭
    #10
    Re: solar generator

    Something to think about with a long-term disaster, you won't need to run a fridge or freezer after a few weeks (your first goal for food is to use up all the perishable stuff first, leave the canned/dried stuff for later). And while having a room with A/C would be a luxury you would do far better long-term with a fan and a spray bottle with water.

    You can support these loads - plus a CFL or two - with a solar off-grid system, yes. But as others have said it won't be cheap. Far cheaper would be an inverter-genset as someone else mentioned above, maybe a 1000 watt model, coupled with a 400-500 amp battery bank plus inverter, and enough fuel to last you just beyond your frozen food supply. Maybe a month's worth. You would drop your fuel consumption by only running the genset 8 hours each day spaced out over several intervals, then the inverter from the battery bank over a few more intervals, for a max of maybe 12-16 hours each day of run-time. Thermal carryover in the fridge will take you the rest of the way in-between the off times. Just make sure you take up the empty space in the fridge or freezer with jugs of water to help with the carryover.

    You could add to this let's say 2-4 pv panels and a small charger - more than enough to keep the batteries at float (topped-off) before the disaster, and then just enough after your fuel is gone to let you run a fan during the day and a CFL or two for a few hours at night.

    After a disaster big enough to take out the grid for more than a month you are going to have bigger worries than sitting in an air-conditioned room. Like where your food and water is going to come from once your supplies run out, and how you are going to keep others from taking the food and water you have. Or worse.
    4.5 kw APC UPS powered by a Prius, 12 kw Generac, Honda EU3000is
    · Share on Twitter
  • ggunn
    ggunn Solar Expert Posts: 1,973 ✭✭✭
    #11
    Re: solar generator
    BB. wrote: »
    Had to read "ggunn"'s answer twice to make sure--But read it closely, for solar panels, most applications need a battery bank to buffer the power from the panels (variable, daytime only) to loads (fixed power requirements, 24x7 need). And batteries are expensive and have limited life (very dependent on application, batteries purchased, etc...

    My sense of the question is that behind it was the idea I have heard so many times - I want to run all my appliances off solar panels when the power goes out. Most folks who ask it have not yet become familiar with the basics of PV systems, so I try to cut to the chase. Yes, my answer is simplistic and there are indeed some things you can do with solar sans batteries, but there is significant understanding which needs to be gained before getting into those applications. I believe that to a first approximation "you can't do it without batteries" is the right answer. The caveats come later.
    · Share on Twitter

Categories