new here recently bought some mixed panels need advice

Caz
Caz Registered Users Posts: 4
Hi guys just came upon 26 panels, 8 x 140watts, 9 at 135 watts, 1x130watts, 4x 123watts, 3x125 watts, one at 110 watts, made by a few different manufactures Sharp, Solartec, Neuton, Mitsubishi, CNPV, Connergy, voltage varies from 17. something to 18. something. The question is can these be tied to together somehow to become a grid tie setup? Do I need more then one inverter, what would you do with these panels if you had them and no solar on your place but wanted to go there??? 

Comments

  • BB.
    BB. Super Moderators, Administrators Posts: 33,422 admin
    In general, these panels would be a bit difficult to mix+match with solar GT inverters. You need to match the GT inverter's input voltage/current specifications. And a mix of random solar panels is not a great place to start.

    The panels you have are probably Vmp~18 volt panels, which are normally used with battery based systems (12/24/48 volt battery systems).

    Your best bet with solar is to understand/define your power needs, then do several paper designs, and finally shop around for devices (solar panels, inverters, batteries, charge controllers, etc.) that will meet your power requirements.

    Do you have any idea of how much power you want (kWH per day of solar power for GT solar, or do you want battery bank power for emergency backup, etc.).

    Also, you need to understand your utility's billing plans for GT Solar systems, and probably building permits and utility approval. Older solar panels may not be "legal or safe" for use with GT inverters that use high array voltages (typically 200-400 VDC or so).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Caz
    Caz Registered Users Posts: 4

    no I don't really have an idea of how much we use a day but it would be on the very low end. I have these panels at this time and would like to incorporate them in a way that I can lower or eliminate my power bills, I realize it is not ideal, I have read that you can do this but the system would not work at it's peak performance because the system would somehow find the lowest common denominator, but my thinking is that 3442 kw is more then we need by a long shot so that would not matter, if I only knew how someone with some experience would personally hook these up. The panels are between 2 and 6 years old.

  • vtmaps
    vtmaps Solar Expert Posts: 3,741 ✭✭✭✭
    Very first step: Talk to your power company... you can't legally grid-tie without their approval.  After you see their requirements, you can judge whether the system they require can ever be cost effective.  They may require engineer's stamps, licensed installers, etc.

    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
  • littleharbor2
    littleharbor2 Solar Expert Posts: 2,035 ✭✭✭✭✭
    I'd set up a small off grid system with the larger panels and place some of your loads on it, something like your refer and computer and TV. Bear in mind the cost of the components will likely be more than you will save in electricity bills but if you got the panels for free you might break even sometime down the road. There's battery maintenance and replacement to consider. It's a good feeling having this dependable back up power source available to you when you have grid failure.

    2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old  but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric,  460 Ah. 24 volt LiFePo4 battery bank. Plenty of Baja Sea of Cortez sunshine.

  • Caz
    Caz Registered Users Posts: 4
    I'd set up a small off grid system with the larger panels and place some of your loads on it, something like your refer and computer and TV. Bear in mind the cost of the components will likely be more than you will save in electricity bills but if you got the panels for free you might break even sometime down the road. There's battery maintenance and replacement to consider. It's a good feeling having this dependable back up power source available to you when you have grid failure.

    yes this is an option perhaps I can set up two of these with say the 9 135 w and the 8 140 w that match or something like that, A Morningstar 45 came with the panels and I may have access to more of them. I would still need a battery bank, that is why the GT seems like a good option. I will check the rules around here, My question still remains, whether or not these small panels can be connected to a GT inverter, however difficult or inefficient that would be, somehow, if the power company are ok with it or am I dreaming or barking up the wrong tree. Maybe I have to consider off grid completely or perhaps sell these panels for a profit a couple at a time to RV owners??
  • oil pan 4
    oil pan 4 Solar Expert Posts: 767 ✭✭✭✭
    Keep the ones you have a lot of like the 8 x 140w, 9 x 135w and maybe the 4 x 123w and sell the rest to buy the rest of what you need from the parent site here.

    Solar hybrid gasoline generator, 7kw gas, 180 watts of solar, Morningstar 15 amp MPPT, group 31 AGM, 900 watt kisae inverter.

    Solar roof top GMC suburban, a normal 3/4 ton suburban with 180 watts of panels on the roof and 10 amp genasun MPPT, 2000w samlex pure sine wave inverter, 12v gast and ARB air compressors.

  • Photowhit
    Photowhit Solar Expert Posts: 6,002 ✭✭✭✭✭
    edited June 2016 #8

    You might be able to string together the 8 - 140 watt and the 9 - 135watt and meet the minimum required voltage for a grid tie inverter. It would be close if you can back feed at @208/240 volts. It would often require the panels to be UL/Etl labeled, though some power companies don't care what's on your side of the inverter.

    "....but my thinking is that 3442 kw is more then we need..." Keep thinking, and maybe look at the math. A Kw is 1000 watts, your panels in this setup would total about 17 x 135watts or 2,295 watts or @2.3 KW. I don't know your loction, but you can likely harvest on average about 4 hours of sun a day as much as 6.5 in some areas of the southwest. Your 2.3 kw's of panels will normally produce about 70-75% of their panel rating. so figure 2.3 Kw x 4hours x .70 = 6.4 Kwh a day. At 10 cents a Kwh that's 64 cents of electric.

    It's rough math but this will give you a realistic, idea....

    The inverter will run about $1000 - 1500, so you'll run a few years before paying it off....

    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
  • Caz
    Caz Registered Users Posts: 4
    I am thinking the payoff period is not that important, I am hoping to create very low overheads as I head into my less productive years. thanks for the input.
  • Skippy
    Skippy Solar Expert Posts: 310 ✭✭
    vtmaps said:
    Very first step: Talk to your power company... you can't legally grid-tie without their approval.  After you see their requirements, you can judge whether the system they require can ever be cost effective.  They may require engineer's stamps, licensed installers, etc.

    --vtMaps
    I totally agree with this advice.
    If your utility does not allow GT setups, don't do it.
    If it does, you will need the proper checks and approvals to get it done.

    If you go with a battery set up - I am trying to do the same thing - keep in mind, your doing this as a hobby, more than likely you won't "save" money,
    I am going to spend upwards of 600 $  on batteries - that would buy alot of grid power . . . BUT - its going to feel real good when the power goes out and I can still watch t.v. with the lights on.
    2 - 255W + 4 - 285W PV - Tristar 60 amp MPPT CC / 3 - 110W PV -wired for 36V- 24V Sunsaver MPPT CC / midnite bat. monitor.
    1 KW PSW inverter 24V / 2.5 KW MSW inverter-24V ~ 105 AHR battery.
    3 ton GSHP.- 100 gallon warm water storage / house heat - radiant floor / rad
    9 -220W PV - net meter - Enphase inverters and internet reporting system.
    420 Gallon rain water system for laundry.***  6" Rocket Mass Heater with 10' bed for workshop heat.
    Current project is drawing up plans for a below grade Hobbit / underground home.
    Google "undergroundandlovinit" no spaces.
  • BB.
    BB. Super Moderators, Administrators Posts: 33,422 admin
    If you do not need A/C, and can use natural gas (or propane) for heating/cooking/hot water--Then it is pretty easy to run your home down to 200 kWH per month (I did ~170 kWH per month a decade or so ago with my family of 4 during the summer with fridge+CFL lighting, laptop computer, and natural gas appliances). Was not real difficult--But adding a freezer in the garage, kids with computers for school, and all of the little tablets, people leaving lights on, etc.... I did not stay there for long.

    GT solar (permitted install) has kept my bill low--But 12+ years ago, my 3.3 kW installation was $30,000 - $10,000 for state and federal rebates+tax credits. And my electric bill has been $10 a month fixed since (was $4 a month until recently). On my second array and 3rd GT inverter (warranty replacements). Have I saved money--Yes. But I also insulated my walls (only had ceiling insulation when I moved in) and replaced appliances with (then highly rated) Energy Star appliances. (natural gas runs ~$20 summer, and ~$60 winter).

    If you want to keep your bill low (and have wife/kids/etc.)--It is a constant struggle to keep energy usage low (every new "toy" seems to be USB powered these days). Wife wants freezer, leave lights, etc...

    Solar power--I would not call it an "investment". If you have to move, I would suggest that it adds little to the value of the home (capital costs lost), and in some cases may reduce value of home (many buyers don't want electrical "stuff" on their roofs). And if something breaks, you are out of pocket to repair.

    If you can get your bill to ~100 kWH per month (or less), then a full off grid solar system can begin to make economic sense. The capital costs of the system is not great--Battery bank replacement will not kill you. And you may "beat" the utility monthly charge increase (they may hit $50 per month in my life time) as utilities need cash flow to keep the local distribution system running.

    Note that going off grid in a city may run you up against city code (will red tag your home if you do not have utility power)--And as people start to drop off grid (because of high costs), those left will have to pay more (and utilities may get PUC to "require" homes to have grid, or even pay for grid if not connected, to prevent "de-electrification"--Just my guesses about a dark future).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset