Solar for $15,000 budget?

nnsharda
nnsharda Registered Users Posts: 10 ✭
in Solar Beginners Corner #1
So what if I had 15,000 to spend on a new house construction, and wanted to go solar? I am grid tied of course.

Panels are confusing, what is the difference between a 275 watt which produces 30V and 8 amp vs a 275 Watt which produces 60 Volt and 5.5 amp? I understand that higher voltage means less line loss....and hot panels seem to lose voltage in the desert heat on top of a concrete house roof.

What about the battery array? why not get a 48 V or even a 120 V array so you can have the least conversion loss when it goes to the house appliances...I may just wait on real Deka Unigy batteries until later, but want to putter around so see if I can actually run the air conditioners, washer/dryer and large screen TV system off just solar.

Still new guy on block so any recommendations with explanation would be appreciated.
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #2
    Re: Solar for $15,000 budget?

    Okay I moved this off to its own thread because it could become a very long thread on its own. :cool:

    To start with there are three different types of solar electric systems: Grid-Tied, Off-Grid, and Hybrid (Grid-tie with battery back-up). Off-Grid and Hybrid systems use batteries; Grid-Tie does not. If your house is/will be grid-tied the you would either have the straight Grid-Tie system or Hybrid type. Any system that uses batteries will be more expensive than one that doesn't.

    Likewise the system type will effect the panel choice. Grid-Tie systems that utilize central inverters (as opposed to micro-inverters) will have arrays with very high Voltage, usually in the neighbourhood of 400 Volts. These are the systems that typically use the high Voltage panels.

    Systems that use batteries usually have panels/arrays of lower Voltage, with nominal numbers of 12 or 24 (panels have 3 Voltages: nominal, Voc, and Vmp). Higher Voltage arrays can be used with MPPT type controllers, but even so most of them will not have 400 Volt arrays (there's only one controller that can utilize such arrays).

    Grid-Tie systems are efficient because they can 'push' all the power they can collect from the panels to the grid.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,642 admin
    #3
    Re: Help me spend $3,000
    nnsharda wrote: »
    So what if I had 15,000 to spend on a new house construction, and wanted to go solar? I am grid tied of course.
    The big things--Roof angle and clear of obstructions (trees, neighboring structures, etc.). And a large enough main panel to connect the size of solar system you think you will need.

    Otherwise--Conservation, conservation, conservation...

    Lots of insulation, energy start appliances, picking stuff that uses less power (laptop computer vs desktop, high efficiency AC/Heat Pump/possibly a heat pump water heater--especially if you don't have natural gas)...

    Take a look through this thread--Lots of random information and links regarding various solar and DYI conservation projects.
    Panels are confusing, what is the difference between a 275 watt which produces 30V and 8 amp vs a 275 Watt which produces 60 Volt and 5.5 amp? I understand that higher voltage means less line loss....and hot panels seem to lose voltage in the desert heat on top of a concrete house roof.
    More or less, not a lot of difference to you, the end user.

    Electric Power's equation is:
    • Power = Volts * Amps (basic equation)
    So, if you double the voltage, you can cut the current by 1/2 and still have the same amount of power.


    What does matter, as you have said, the higher the voltage and the lower the current, the farther you can run your power and/or use smaller gauge wiring.


    Grid Tied solar is usually setup around 400 VDC for Vmp (voltage maximum power). But, it does depend on the vendor/model and some other issues (plus there are "micro" inverters that connect directly to one or two solar panels, then to your 240 VAC power line/branch circuit).

    What about the battery array? why not get a 48 V or even a 120 V array so you can have the least conversion loss when it goes to the house appliances...I may just wait on real Deka Unigy batteries until later, but want to putter around so see if I can actually run the air conditioners, washer/dryer and large screen TV system off just solar.
    In general, you design either for Grid Tied Solar (no batteries, just solar panels and a GT inverter--the lowest costs, most efficient, and least amount of maintenance)--Or you go for a battery system... Pure off grid solar (usually no power lines nearby) or a Hybrid System--Which is (more or less) a Hybrid inverter that can do both off grid and grid tied solar, plus a large battery bank (lots of costs, losses, and maintenance issues).

    It is very difficult to, cost effectively, add to a small system; and it is not usually practical to convert from GT to Off Grid/Hybrid (the hardware is too different, and of course, there are the batteries). Yes, you can use the solar panels over (usually with re-wiring)--but that is about it.
    Still new guy on block so any recommendations with explanation would be appreciated.
    Design/build your home with conservation in mind, measure your power needs, and define your requirements (save money, emergency power with Grid Tied, off grid, backup power + genset, etc.).

    Home Power Magazine is an interesting read... Tilted towards off-grid--but has lots of information that you can use for conservation projects too.

    Home Power Magazine

    And read/plan/do cost roll-ups before you spend your first dollar...

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • nnsharda
    nnsharda Registered Users Posts: 10 ✭
    #4
    Re: Solar for $15,000 budget?

    1)R-60 in the ceiling.
    2)R-24 walls.
    3)Passive attic ventilation with air grills under all eaves and a ridge vent to exhaust the hottest air in the attic, thinking about attic fan. Extra insulation around the air ducting and all piping....the installers rolled their eyes but I checked everything every day...
    4)American Standard SEER 22 split system electric air conditioners (the "bomb" according to my builder.)
    5)Gas hot water and subfloor heating with hot water, coupled with 75 square feet solar hot water panels my plumber made for me off the builditsolar.com website.
    6)Large deciduous trees in the south/west.
    7)Full basement almost always 15degrees cooler than main floor in summer.
    8) CFL bulbs and LED rope lighting per the electrician, a personal friend.
    8)11,000 square foot multifamily house...two sets of parents, all four with health problems so will be having continuous moderate electical loads for wheelchairs etc. Nursing homes are truly filthy places....

    The area for placement of panels is top of roof, south facing, 30 degree slope, approximately 600 square feet. An additional 500 square feet available on west facing rooftop, also virtually no sun.

    Generally no problems with the grid reliability in Las Vegas, but the new "digital" meters seem to always read more usage than anybody was paying for before the forced upgrade, would be nice to have a way to verify the actual electricity usage...

    I estimate the daily usage to be 75-100kwatt. So would need a really, really large system. Probably not possible to get fully off grid?
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #5
    Re: Solar for $15,000 budget?

    75 to 100 kW hours per day?
    You could do that, but not with 500 square feet of panel space. And not without winning some serious money at the casino.

    Grid-Tie is probably your best bet here. Hopefully there's some rebates or tax breaks available to help defray some of the capital expense.
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  • nnsharda
    nnsharda Registered Users Posts: 10 ✭
    #6
    Re: Solar for $15,000 budget?

    1000 square feet of panel space.

    40 panels of 275 watt panels at .9/watt is $10,000. Will request the higher voltage panels to cut down on wire sizing and line loss. 11kw-hr for 6 hrs gets 66KW/Day average. Cut 30% for efficiency loss, now at 44Kw/day....maybe half the daily usage?

    Would appear that hybrid and off grid are impossible...so stay with grid tie.

    Now the questions are:

    Inverters, which one(s)?
    Charge controllers, which one(s)?
    What else needed for system?
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  • solar_dave
    solar_dave Solar Expert Posts: 2,397 ✭✭✭✭
    #7
    Re: Solar for $15,000 budget?

    If you are going grid tie find out about your utilities net metering plan.

    Is that 75-100 kWh your peak summer usage or are you using that now? That is where a net metering plan plays in, you generate now for use later. Get your annual usage and use those figures in your planning.
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  • rollandelliott
    rollandelliott Solar Expert Posts: 834 ✭✭
    #8
    Re: Solar for $15,000 budget?

    "Inverters, which one(s)?
    Charge controllers, which one(s)?
    What else needed for system? "

    Are you planning on installing this yourself? and speding a lot of time researching all the components and putting it together......or hiring someone?

    if you are going to hire someone I'd just let them give you recommendations and then double check with the board members.
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  • nnsharda
    nnsharda Registered Users Posts: 10 ✭
    #9
    Re: Solar for $15,000 budget?

    R&E:

    Have read several of the threads, show very clearly that the "installers" don't have much clue yet. Also met with several of the solar companies here, either they won't specify what exact components they will install up front or they don't understand either when pushed for details and explanations. Only reputable company that seemed to know what to do wanted nearly 100K for the installation....a little research here and at library and speaking with a Chinese friend looks to cut that down to 15-20K (Hope). Of course I won't be installing myself, but some knowledge when dealing with and finalizing contract sure helps keep the cost down to a point where solar may become cost neutral over 5 yrs. Well thanks anyway guys.
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  • solar_dave
    solar_dave Solar Expert Posts: 2,397 ✭✭✭✭
    #10
    Re: Solar for $15,000 budget?

    You should be able to get an installer to do it for about $4.00-$4.25 a watt. That is about a 5000 watt system before any rebates or tax credits at $20,000.
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  • rollandelliott
    rollandelliott Solar Expert Posts: 834 ✭✭
    #11
    Re: Solar for $15,000 budget?

    and if you are going to do it yourself I'd say around $2/watt for everything or about a 10kw system which is typically big enough to take care of an entire family's electricity needs and then some.

    Might want to consider getting all the components and then doing a partial install like mounting all the panels and having an electrician do the final touches., that route will probably give you most bang for buck.
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