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Thread: How many Batteries and Panels I need

  1. #1
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    Apr 2012
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    Unhappy How many Batteries and Panels I need

    Dear all I am residing in sunny area. I want to use solar system for my house . I want to run a Refrigeration, 03 fans 03 energy savers of 20 watts each 01 LCD TV,
    my questions are
    How many solar panels of what watts I need?
    How many batteries do I need and what power? that is required day time and night time also I need 12 hours back up.
    which type or model invert er & Charge control I should buy ?
    what is better tie grid, off grid ?
    Which circuit is better 24 or 12 volts
    Thanks in advance for cooperation

  2. #2
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    off grid retirement in Northern Calif
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    First, you need to calculate your loads -

    Then look up your sun hours on PV watts http://www.nrel.gov/rredc/pvwatts/ (has global listings too)
    (for calculating, use a 1Kw array, and then we can divide that down)

    Then when you have your loads calculated in WATT HOURS, and how many hours of sun you have in the short winter days.

    But until we know what watt hours you use, it would just be wild guesses.

    First, read this
    http://www.solarpaneltalk.com/showth...Battery-Design


    then:
    Start by calculating Watt Hours for everything. a 80 watt laptop for 4 hours is 320 watt hours.
    A 7 watt night light for 24 hours is 168 watt hours. Half as much power as a laptop, but nowhere near as fun. A 1200w microwave for 3 minutes is 60 watt hours. Hey - you CAN haz popcorn.

    Add the watt hours for everything you have, and then we can advise you what is reasonable.

    If this is just for weekends, we're likely to advise just one panel, and a small generator to keep the battery charged while you are there. As you increase your time living in the place, the cost of the expensive panels pays back sooner.

    Panels work the same way - 180W for 5 sunny hours gives 900watt hours on paper, but after you calculate all the system losses, you only have 450 watt hours. A full half of what the panel nameplate implys.
    Since the dawn of time it has been mankind's dream to blot out the sun.
    Montgomery Burns

    "Always listen to experts. They'll tell you what can't be done and why. Then do it."

    spreadsheet based voltage drop calculator:
    http://www.solar-guppy.com/download/...calculator.zip
    http://www.solarpaneltalk.com/showth...oss-calculator

    http://www.mike-burgess.org/PVinfo_2.html

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,
    battery lugs http://tinyurl.com/LMR-BigLug
    Setting up batteries http://tinyurl.com/LMR-NiFe

    gear :
    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 || || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

  3. #3
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    Apr 2012
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    Smile How many Batteries and Panels I need

    Thanks for your cooperation in this regards. In my area sun in winter is almost 8 hours clear and in summer about 11 hours. I need load from solar initially,
    03 energy saver bulb of 20 watt each up to 12 hours
    02 ceiling fans for 12 hours
    01 pedestal fan for 12 hours
    01 refrigerator medium for 24 hours
    This is all what I want let me help to choose the correct number of panels and batteries and types of batteries. later on I can increase the system if its good.
    Thanks in advance and again thanks for reply waiting for your reply

  4. #4
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    Quote Originally Posted by ayyaz View Post
    Thanks for your cooperation in this regards. In my area sun in winter is almost 8 hours clear and in summer about 11 hours. I need load from solar initially,
    03 energy saver bulb of 20 watt each up to 12 hours
    02 ceiling fans for 12 hours
    01 pedestal fan for 12 hours
    01 refrigerator medium for 24 hours
    This is all what I want let me help to choose the correct number of panels and batteries and types of batteries. later on I can increase the system if its good.
    Thanks in advance and again thanks for reply waiting for your reply
    Again missing information
    we got the lights but the other things we need are the draw on the fans in watt hours and the refrigerator for a normal day of running.
    Simply stating a medium refrigerator is not enough information and you will either spend too much on a system to power it or you will be left in the dark with no power.
    Rich
    WWW.solarsaves.net

    NABCEP certified Technical Sales Professional

    http://www.solarpaneltalk.com/showth...Battery-Design

    http://www.calculator.net/voltage-drop-calculator.html (Voltage drop Calculator among others)

    www.gaisma.com

  5. #5
    Solar Fanatic
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    Quote Originally Posted by ayyaz View Post
    Thanks for your cooperation in this regards. In my area sun in winter is almost 8 hours clear and in summer about 11 hours.
    No you do not. No place on earth receives 8 Sun Hours in winter. more like 2 or 3.
    MSEE, PE

  6. #6
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    Oct 2011
    Location
    Wyoming
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    549

    Default

    Quote Originally Posted by ayyaz View Post
    Thanks for your cooperation in this regards. In my area sun in winter is almost 8 hours clear and in summer about 11 hours. I need load from solar initially,
    03 energy saver bulb of 20 watt each up to 12 hours
    02 ceiling fans for 12 hours
    01 pedestal fan for 12 hours
    01 refrigerator medium for 24 hours
    This is all what I want let me help to choose the correct number of panels and batteries and types of batteries. later on I can increase the system if its good.
    Thanks in advance and again thanks for reply waiting for your reply
    Daylight hours and solar insolation are 2 different things. As SK stated, no place on earth has those kind of numbers for solar insolation.

    As for usage we sill onlt have part of the equation. How many watts (amps and voltage) does the ceiling fans, pedistal fan, and frig use?

    You might want to get a "kill-a-watt" meter to measure each item over the course of a week or 2 to get an daily average.

    WWW

  7. #7
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    This misconception comes from the 'salesman's' term of sun hours which is meaningless but refers to insolation in kW per day - kind of dumbed down to where it creates confusion

    Much better to use insolation in kWh/day - which any science or engineering discussion would use.

  8. #8
    Junior Member
    Join Date
    Apr 2012
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    Default Full Information....

    Quote Originally Posted by ayyaz View Post
    Dear all I am residing in sunny area. I want to use solar system for my house . I want to run a Refrigeration, 03 fans 03 energy savers of 20 watts each 01 LCD TV,
    my questions are
    How many solar panels of what watts I need?
    How many batteries do I need and what power? that is required day time and night time also I need 12 hours back up.
    which type or model invert er & Charge control I should buy ?
    what is better tie grid, off grid ?
    Which circuit is better 24 or 12 volts
    Thanks in advance for cooperation
    I see you want to replace grid to off-grid independence...
    1 Before please tell where you stay
    2 Watt of each appliance
    3 Energy backup of how many days you need..

    Ill let you know exact configuration...

  9. #9
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    May 2009
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    off grid retirement in Northern Calif
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    I see you want to replace grid to off-grid independence... ...
    You do understand this will co$t you a lot of money. Grid power at 10 cents per KW hour, and self generated and stored in batteries that have to be replaced, costs about 10x as much. Much more cost effective to use Grid-Inter-Tie (Grid-Tie) and have a small generator for power outages.
    Since the dawn of time it has been mankind's dream to blot out the sun.
    Montgomery Burns

    "Always listen to experts. They'll tell you what can't be done and why. Then do it."

    spreadsheet based voltage drop calculator:
    http://www.solar-guppy.com/download/...calculator.zip
    http://www.solarpaneltalk.com/showth...oss-calculator

    http://www.mike-burgess.org/PVinfo_2.html

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,
    battery lugs http://tinyurl.com/LMR-BigLug
    Setting up batteries http://tinyurl.com/LMR-NiFe

    gear :
    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 || || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

  10. #10
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    May 2012
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    Default

    Quote Originally Posted by Mike90250 View Post
    That thread is missing information,

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