Energy I'm looking to install grid tied solar with shtf options

Discussion in 'Off Grid Living' started by oil pan 4, Jun 24, 2018.


  1. oil pan 4

    oil pan 4 Monkey+++

    Ideally I would like to get solar panels.
    In a perfect world I would just build an off grid system and be done with it. But I don't have unlimited money or time to do it.

    Need to start some where and end up some where. Ideally I would start with a grid tie setup, but grid tie and going off grid setup couldn't be more different from each other. The only thing they have in common is solar panels and that's it. Even then if you don't get the ideal solar panels for your grid tie they won't exactly be the best for off grid use later on. Often grid tie setups use 60 cell panels just serried together for insane high DC voltages and 24 or 48v off grid setups use various arrangements 72 cell panels. Grid tie can use 72 cell panels, just serried up for insanely high voltage.

    In grid tie the solar panels are typically wired for 100 to 600 volts DC. So this way you can move all your power with one pair of relatively small wires to your grid tie inverter.
    In off grid setups you panel voltage is usually 24 or 48 volts normal working voltage and up to about 150 volts depending on your charge controller or up to 600v if money is no object. You use lots of individual wires or a few real thick ones to move your panel power to a charge controller and the charge controller charges up your batteries.
    A higher volt charge controller can pay for its self just in copper savings, if you pay retail for your wire depending on how far your panels are from the batteries.

    Grid tie inverters are useless when the power goes out. With no power grid input signal they won't make any power that's kind of a key safety feature too. That's just how its always been. And that's what they taught us when I was going to school to earn my associates in applied science for wind and solar power generation. There isn't any reason that a grid tie inverter can't produce at least a little useable 120v AC power off the raw incoming solar power while the sun is up, they just aren't made that way.

    Well sunny boy was like hold my beer and watch this and built a line of grid tie inverters ranging in power output from 3kw to 7kw that have a dedicated off grid power supply. So if the power goes out you can get up to 2,000w out of the secure power supply.
    Meaning you can get up to 2,000w out of the built in receptacle on the side of the inverter after the power goes out, as long as the sun is up. The main power going to your house cuts out when you loose utility power.
    I have a feeling it won't deal with surge currents very well. But it's better than what you get with all the previous generations of grid tie inverter.
    The best part about it is the price is almost the same as any other name brand inverter.

    But for me I think I found what I need. And it's a little expensive. A radian 4kw hybrid inverter.
    These take 48v DC panel power and can be used as a grid tie inverter only, a stand alone inverter with batteries or both. But they are expensive. Around double the price of a typical grid tie inverter.
    When my solar and wind power school books were published, most of them between 2009 and 2012, these things didn't exist or were so new the authors hadn't seen them. So they are fairly new.

    Maybe I will do both. Start out with a sunny boy with secure power supply, 72 cell panels that can easily be reconfigured by easy access junction boxes for different applications later on then next solar upgrade get a radian hybrid system with batteries, then charge controller solar panels and all later on.
     
    Last edited: Sep 16, 2018
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  2. TnAndy

    TnAndy Senior Member Founding Member


    May not have been in your books, but Outback has been making their GTX series hybrid inverters for a long time before that. I set my system up starting in 2008 with a pair of GTX2500 inverters that normally grid tie, but can switch to off grid mode if the grid is down. I have 6,000 watts of 72 cell panels feeding 3 charge controllers and a 1200 amp/hr battery bank. The Radian is simply the next generation of their hybrid inverters.

    Later I added another 5,000 watts of grid tie only using Enphase microinverters (one per solar panel) which do shut down it they sense no grid power. However, I'm convinced those could also be re-configured to provide a daytime boost of power to my base system, using the Outback base as the "grid" power source, and they would provide up to an extra 5k of power during sunny days.
     
    Last edited: Jun 24, 2018
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  3. Altoidfishfins

    Altoidfishfins Monkey+++ Site Supporter+

    Certain solar power companies sell grid tie systems with battery backup. It's all figured out, all you do is connect the dots. Check around on the web.
     
  4. oil pan 4

    oil pan 4 Monkey+++

    The text books were more centered around facility and utility level solar installs.
    That may have been why no mention of hybrid inverters.
     
  5. BenP

    BenP Monkey++ Site Supporter+

    The Schneider 4024 that I use will let you use the grid to supplement your solar as needed.
     
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  6. BTPost

    BTPost Stumpy Old Fart Snow Monkey Moderator

    I have been running an OLD Trace SW4024 since about '95 that has GridTie Capability built-in... I have NO USE for that capability here since there is NO GRID to tie to... So I run the Summer PowerHouse Feed to the Grid Tie IN, and Winter Powerhouse to the Generator IN.... but Setup the configuration for NO Back-feeding the Grid, and call it Good.... Someday I just might install my Backup Trace SW4048 Inverter, and add the Last string of L16HD Batteries so I have a 800 AmpHours @ 48Vdc instead of the 1200 AmpHours @ 24Vdc that I have NOW...
     
  7. Tevin

    Tevin Monkey+++

    Grid tie solar with SHTF option is possible but expensive, even if you do it yourself. You also have to deal with permits and inspections for anything that is tied to the grid.

    All the glowing stories about homeowners saving tons of money with grid-tie systems is a smoke and mirrors hustle. These systems "make money" only because of the games the government plays with taxes, subsidies, power company buy backs, etc. There are very, very few places in North America where you can make your own electricity cheaper than you can buy it.

    I say go with a grid-tie, or an off grid battery setup, but not both. And if you're doing it for the money, you're in it for the wrong reasons.
     
  8. oil pan 4

    oil pan 4 Monkey+++

    I just said the sunny boy with 2,000w secured power supply serries inverters costs just as much as any other name brand grid tie inverter that becomes useless when the power goes out.
    Difference being the secured power supply gird tie inverter can still make up to 2,000w of continuous, 120v 60hz power to as long as the sun is up when the utility power is out.
    Guess someone finally listened to the complaints from angry customers who spent $10,000 to $40,000 or more on a grid tie system and found out the hard way a normal grid tie system produces no power when the utility power goes out.

    I don't think it's going to be like printing my own money. I figure a 4kw system will save/earn around $1.50 worth of power per day. Then every day the power goes out that $1.50 is worth of power is worth more like $10 or $20 per day if not more.
     
    Last edited: Jun 24, 2018
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  9. oil pan 4

    oil pan 4 Monkey+++

    The only 24 and 48 volt grid tie micro inverters I can locate appear to be cheap made in china junk.
    Yes, plenty of cheap 24 and 48v grid tie inverters of questionable safety and quality are widely available.
    I'm not going to be using them.
    Plus if there are name brand 24 to 48v micro inverters out there, they are micro inverters, the idea being you wire them up at the solar panel and send 120 or 240v power to your house from the solar panel area.
    If I wire up panels for 48v I want all that 48v power to go back to one central location that in the future could house a charge controller and battery bank if I so desire.

    What I was getting at is a typical grid tie setup and typical off grid setup are so different you can't easy change over from one to the other, unless you design the system for that from the beginning.
     
    Last edited: Jun 24, 2018
  10. oil pan 4

    oil pan 4 Monkey+++

    So these hybrid inverters have been around since the mid 90s?
    The courses I took were centered around utility and facilitie solar installs. I'm pretty sure I was the only person to read all those books cover to cover and remember seeing no mention of hybrid inverters.
     
  11. techsar

    techsar Monkey+++

    Yup...I have a couple of the SW2512 inverters that, like Bruce's could do grid tie, but that function is turned off...but I can still use the grid to charge the batteries or provide a bit more power if required.
    IIRC, mine are about ten years newer.
    And not a single permit or overpriced "solar installer" was required.
     
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  12. Borrego

    Borrego Monkey

    My recent experience with solar at my off-grid location (see recent thread), has led me to consider doing a similar thing at my 'regular' home. Installing the exact same system (48V/2000W) and 'shaving' a few circuits permanently....(kitchen, 2 bedrooms, main area).
    To convert our entire house to solar would be cost prohibitive ($20 - 30k), but I can do the above 'shaving' for $7k.
    I am far from an expert but this is just my plan......
    BTW, I probably will not apply for a permit. I am familiar with electrical code and see no reason to get the Govt involved......
     
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  13. techsar

    techsar Monkey+++

    Before a single penny is spent, know what you are going to be powering, how much power it needs and for how long, and don't try to cut corners. Shortcuts and over optimism are quick and easy ways to be disappointed with your system...and can be dangerous to boot.
     
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  14. oil pan 4

    oil pan 4 Monkey+++

    I'm not hiring an installer.
    I'm hiring a kid to dig the holes for the ground mounts and that's it. I don't have a day to waste digging holes.

    The electric coop said I don't need any permits from them.

    I'm powering the Roosevelt coop power grid. I'm not building an off grid system yet. That's still years and at least $20,000 away.

    This sunny boy "secure power supply" grid tie inverter runs 100 to 550 volts DC input.
    The only name brand multi Kw grid tie inverter I can find that runs 48v input is the radian hybrid and it's a 4kw inverter that runs around $2,500. (Double the price of a high end grid tie only unit)
    I actually did find some 48v name brand micro grid tie inverters. But they are useless when the power goes out.
    I don't know if the big hybrid inverters like the radian will provide stand alone power without batteries. I wouldn't count on it.
     
  15. TnAndy

    TnAndy Senior Member Founding Member

    If your utility has gone to the new smart meter, they can tell a whole lot of things from it....one being if any power comes back thru the meter from your side. That will happen eventually the day your generation is above your house use....like a nice spring day when no heat/air is used, and you're away from home not using lights/computer/etc. THEN they will become involved if you don't have an interconnect agreement.
     
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  16. TnAndy

    TnAndy Senior Member Founding Member

    Yeah, me neither...... :D

    [​IMG]
     
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  17. oil pan 4

    oil pan 4 Monkey+++

    If you have a dumb smart meter they count any power flow as consumption.
    So any power you send to the power grid is counted as consumption.
    You need a net meter or cogen meter to count power you send out.
     
  18. BenP

    BenP Monkey++ Site Supporter+

    The Schneider Electric Conext SW 4048 should do what you need, I think they run about $1500.
     
  19. arleigh

    arleigh Goophy monkey

    I stared off making a UPS to run my computer off grid ,mostly because the grid was unreliable and irresponsible .
    Later I began applying solar panels I could afford and adding them to charging the battery and eventually a battery bank ,because I had grown in my DC usage to lighting through out the house . There were no LED in those days so al I had to work with was automotive lighting . My reasoning was that DC lighting lived longer and pulled less amperage than AC. I even took burned out incandescent lights and replaced the tungsten with a quartz bulb , I do the same now with LED for my DC lighting.
    The Homes I've lived in for the last 20 years I ran alternative wire on the 12 volt lines and most of my lights are DC.
    The grid is still tied to the house ,running the refrigerator and washing machine and dryer and in the shop my welder and air compressors and other equipment . and so far my electric bill is $20.-$40. a month sometimes higher during the winter months .
    When the grid fails around here it is rare and not for long. so having to power the frig on solar has not been necessary however I do have inverters capable of running it, and if push comes to shove I have generators capable of running most of my other equipment if necessary . I have picked up other solar panels for the future, and I need to replace some of the 10 year old 6 volt deep cycle golf cart batteries roughly $100. each . They have served me well .
    As a mechanic I play with building things and I use DC power for some of those projects .
    Building a solar system does not have to be done in a day or a week or a year ,but you do need to plan ahead of time toward the end you hope for . I installed my solar and battery system on my shop trailer ,that way it moves with me where ever I happen to go. Solar does not belong to the house,,, the solar belongs to me .
     
  20. oil pan 4

    oil pan 4 Monkey+++

    Will that Schneider one produce any 120v power with out a grid signal?
     
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