off grid set up details need help

sunspotsunspot Registered Users Posts: 6
I wish to ask about an off grid solar system. im sorry i dont know anything really but want to learn and do it right away. I also apologis that I dont know how to organize this better. I have done my homework and am here to learn with you all. I have a great chest frezer fridge conversion i can tell you about.

I have done much research, lol, but it is a humbling experience.

With 1000 watts from about 16 panels of kaneka 60 watts each, how can i wire them to batteries, inverter, and charge controller? which charge conrtoller and inverter do i need to use? Can you suggest a do it yourself wrack system, since I need to budget carefully. I designed a roof extension that will be a porch roof too for sitting under. it will be wood and sturdy with 6 x 4's and 3/4 plywood, or is that a no no due to rain and snow? what are my options for frugal do it yourself? and i have not designed yet a way to adjust the wrack for winter/ summer differential. all thos panels will be heavy and im a slender but strong girl, still no on can lift all those panels, even just one edge. i wonder about a motorized lift, if inexpensive.

I figure my energy needs are less than 2.2 per day as long as the separate passive solar water heater works well enough, otherwise I may want to use a small water heater, it is 20 or 30 gallons.

I see a panel that is priced good can I mention the name? it comes as 60 watt and is .98/ watt. How many would I need to cover my usage? Like if you use winter as a calc to cover the weaker sun exposure, like then if I get a 1 kw system, do I multiply by 2 hours sun and get 2 kwhours per hour? per day? so would a 1000 watt system give me 2 kw per day or per hour in winter?

And what about tankless water heaters, if I got a small one, they can heat water instantly, but require high energy for a couple minutes so what is the most draw I can get from a 1000 watt system at one time?

What does a 1000 watt system mean, per hour or pr day i will gt about that much?

I wish to have batteries for back up, so how many and what type? where is good to buy them? i need to run these items:
chest freezer 1 kw per day
chest fridge hopefully .1 per day
computer 60 watt x 5 hours =.3kw
stand alones, can be run while freezer is unplugged to spare energy :
vacuum
tools, seldom
radio, seldom
water heater, only if solar water heater not working well, unknown, not built yet, lol
some spare watts in case of anything

Comments

  • RCinFLARCinFLA Solar Expert Posts: 1,461 ✭✭✭✭
    Re: off grid set up details need help

    First, forget the electric hot water heater and tankless hot water heater. Doing this with solar electric is not practical. If you need a backup hot water heater consider a small propane unit.

    Your 960 watts of panels will barely cover your chest freezer. Assume 50% from panels and double your expected kWH consumption.

    1 kW of PV is about the point you should use an MPPT charge controller.

    Also consider what the startup surge may be on the fridge units. The fridge's prefer true sinewave inverters. Be aware of the no load consumption on inverter. A small sinewave inverter can consume 50 watts just sitting there with no output loads.
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭✭
    Re: off grid set up details need help

    Some basic design info for you:

    Starting with the loads is the right thing to do. Getting rid of any and all electric heat loads is a must. Then you need some idea of 1). what will be the maximum Watts at any given time and 2). what will be the total Watt hours used during a 24 hour period. The first will tell you how big an inverter you need. Do not rely on an inverter's "surge rating" for this; it's only there for "oops" situations. If you have any induction loads such as a refrigerator, you will want a pure sine wave inverter as the MSW type doesn't work well wit that kind of load.

    The Watt hours per day will give you an idea of how much battery capacity you need. Basically: Watt hours divided by system Voltage = Amp/hours. You should have enough battery capacity to supply this at a maximum Depth Of Discharge of 50%. In other words if you need 100 Amp/hrs to run things your batteries should be at least 200 Amp/hrs.

    Once you have the batteries figured out you can determine how much solar and what charge controller you need to recharge them. The recommended charge rate is 5% to 13% of the batteries' Amp/hr capacity.

    You need to get this basic design down with some 'ballpark' figures before you start looking at individual components to see what best fits your needs, including budget. Always consider the future with its inevitable increase in loads. Trust me: we've all been there, done that, completely redesigned as a result! :p

    Once you know what panels you're working with you can determine where and how to place them. Where your site is will make a difference in design too; you can run the PV Watts program to see how much power you can expect to harvest in your area.

    You can start by reading this forum 'til you go cross-eyed; lots of info here, but it takes time to digest.
    To start with:
    http://forum.solar-electric.com/forumdisplay.php?f=14
    http://www.windsun.com/Batteries/Battery_FAQ.htm

    P.S.: Glad to see you've found the "thread button". Sorry about the slow response.
  • sunspotsunspot Registered Users Posts: 6
    Re: off grid set up details need help
    RCinFLA wrote: »
    First, forget the electric hot water heater and tankless hot water heater. Doing this with solar electric is not practical. If you need a backup hot water heater consider a small propane unit.

    Your 960 watts of panels will barely cover your chest freezer. Assume 50% from panels and double your expected kWH consumption.

    1 kW of PV is about the point you should use an MPPT charge controller.
    ok please tell me more about this. i know this part costs alot more. can you tell the negatives if i dont use it, due to the cost? maybe i can adjust for it somehow or maybe i need to hold off until i can get a MPPT


    Also consider what the startup surge may be on the fridge units. The fridge's prefer true sinewave inverters. Be aware of the no load consumption on inverter. A small sinewave inverter can consume 50 watts just sitting there with no output loads.

    50 watts per day?

    ok, no hot water for me. i believe i can cope with that. may i ask further about 960 watts - woould this formula be correct: (960 watts x 5 hours minimum sun hours winter x .85 efficiency)/1000 = 4.08 kw per day.

    please help me know for sure about production since your figures and mine do not match at all. do you have a solar system, if so what do you produce and how many watts do you have, thanks

    chest freezer 1.0 kw per day
    960 watts should produce minimum of 4 kw day. if a system produces only half that then it should produce 2 kw but if i need to double my loads then things dont match up. why double loads? i have a fridge on a kil o wat for 1 month to get total kw. isnt kil o wat pretty accurate? if a 960 watt systam wont produce 1 kw per day then i need to know about this for sure. field data is good so anyone have a system and hat production are you getting? thanks
  • sunspotsunspot Registered Users Posts: 6
    Re: off grid set up details need help
    Some basic design info for you:
    thanks alot
    i am messing with the data you sent me
    imade some follow up questions, if you pls to read them
    i will send once i process this more

    i have revised my questions many times
    i wish i didnt have so many of them.
    but your response let me to the battery faq, then to a forum of more tidbits, and had many tips and formulas

    you are so cool

    thanks alot
  • mike95490mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: off grid set up details need help

    Best to take a chance, and try your fridge/freezer on the Morningstar 300W sure sine. I don't know it peak power, they rate it a 600w for 10 min. But the idle/standby/no load power is very low on this unit.
    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 ,

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