14 qcell sf310m-60 panels. Now what

luminescentluminescent Registered Users Posts: 4
hi I just bought 14  sf310m-60 solar panels For $110 each.  With the option to buy more.  
Aparrently they are sold as blemish. They show data info sticker as  32v output with 9.44 amps,  max system voltage 1000v per panel. 
I’m in the process of building the ground mounts now.  
Question:  what’s next.  I’m 💯 new.  I do have wiring and electrical background but on residential homes and vehicles.  
What connectors. What wire sizes. What solar charge controller. What batteries, connected in what configuration?? And how many... hoping to make it a grid Tied system with the utilities as a backup ??  I’m hoping to expand to 10kw system. 
My current daily use is 24kw-46kw so I may have to split my power to priority and luxury. 
Priority being solar panel feed freezer and fridge and internet. 
I’m sorry if this seems simplistic, but I am new and unaware of what is available. No resources, or references to gain knowledge or point of reference for my system. I simply saw what I thought was a good price for panels with no shipping and took a leap of faith. 


  • luminescentluminescent Registered Users Posts: 4
  • mcgivormcgivor Solar Expert Posts: 3,854 ✭✭✭✭✭✭
    Welcome to the forum @luminescent

    Bought a set of mag wheels 5 hole bolt pattern slightly blemished but the price was right, what car do I buy and what accessories should I consider, the  priority would  getting to work and the occasional road trip....... B)

    On the serious side, when building a system the loads are the first thing to calculate, then the batteries needed to support the loads lastly the amount of PV needed to keep the batteries healthy which in turn would govern the size of the charge controller.

    There other things to consider but basically this would be where to begin, I'm by no means attempting to be condescending, we all have made  rookie mistakes and from that hopefully you'll avoid some of the pitfalls that are all too common.
    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery with Battery Bodyguard BMS 
    Second system 1890W  3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah LFP 24V nominal battery with Daly BMS, used for water pumping and day time air conditioning.  
    5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
  • PhotowhitPhotowhit Solar Expert Posts: 5,909 ✭✭✭✭✭

    Now figure out what you want to do and what your goals are!

    Off grid battery based systems are usually very expensive per kWh. I'm about as cheap as I've ever heard (30+ years on solar forums/BBs) at about 30 cents a kWh and that includes at least 50% (perhaps more like 60-70%) energy that is consumed without having to store it!

    So is your goal saving money? saving the environment? Having a backup source of energy? Energy independence?

    Once you figure answers to those questions, you can move on to; How do I do that?

    Here's a short info blub I did on Grid vs Off grid;

    First you need to decide if you want a grid tied or an off grid system.

    In most places there will be NO long term savings with off grid electric! Off grid requires a much larger system than a grid tied system for the same amount of electric, you can usually figure about 3x the size. In addition you will most likely need alternative sources of power usually a generator for long periods of overcast weather.

    Off grid requires a larger system because it has high system losses, roughly 50% for stored energy with flooded lead acid batteries! In addition, the system must reach a fully charged point a few times each week for battery health. Once fully charged the system either is idle or can be used to power opportunity loads. These are loads that you don't normally use solar electric for, like water heating.

    In some locations grid tied can be cost effective and save you money long term. These systems basically use the grid as a battery bank. They push electric back into the grid when you are producing more electric than you generate and draw energy from the grid when you aren't producing enough to cover your needs. In most states 'net metering' is still the law. The utility company will off set the energy use 1:1 for the energy you push back into the grid. Much less equipment, not batteries which require maintenance and replacement.

    This obviously isn't very cost effective for the power companies which don't get a return for the cost of delivering the electric you your home. So electric companies have been splitting out the energy infrastructure costs and restructuring how they bill you so that the net metering only applies to the energy that is delivered and there is still a separate charge for the infrastructure. Some times this is in the form of a line fee, some times it is a high user fee. Depending on this structure will help determine if it is cost effective for you.

    I would suggest checking with your power company and possible having a local solar company do a cost analysis. Most will do an analysis for free. 

    Either solar system will require direct exposure to southern sky to effectively capture solar energy through out the year.

    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.
  • luminescentluminescent Registered Users Posts: 4
    Thank you for the info.  I’m hoping to operate certain items like freezer and fridge and whatever else I can support on the panels I have. Ultimately building a system to support my 220v well also. Or switching to a 12v pump. 
  • luminescentluminescent Registered Users Posts: 4
    I realize, as a professional, you would build a systems to suit your needs.  Like buying a truck to haul the load you plan on hailing, is the best practice. 
    Unfortunately, I haven’t made a plan. And to be honest, I am not sure how much money I can spend on the system. 
    The panels were cheap, maybe poor quality.  I’m not sure. I saw an opportunity to get started, the way one might see an old car that may be fixable. 
    Now I have the panels... 
    basically, What load to put on the system.  
    I have a kill-a-watt plug in device to determine the average usage of each appliance.  So... 
    with that I have solar panel wise, what do you suggest I run with off grid power. Net metering isn’t allowed with Bowie Cass Electric Coop. So I’m going to choose certain appliances like fridge, freezer and whatever else I can run off solar. 
    If I’m understanding, I should buy enough batteries to handle  310v x14..   or 9.44amps x14.  And a charge controller to handle that too. 
    question 1. Can I buy a charge controller that can handle double that amount and it still work on my system giving me the option to expand. 

    That way I can buy more panels and batteries as needed?? 
  • mike95490mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Stop Buying Stuff ! ! !

    Stop thinking you know what you are doing - because you dont - even if you did wire in a 240VAC pump.

    Get the yellow / black book Solar Power for Dummies.  You can find old editions on the web, or new editions in bookstores..
    Then, after you get some of the terminology down, come back here, read the basics posts

    You are describing that what you want is a hybrid system, the most expensive and complicated of PV solar setups.

    Any PV setup is going to need to be designed, starting first by itemizing your loads. How many watt hours.  Peak starting power requirements.

    unless you currently experience frequent or seasonal power outages, a simple Grid Tie system with a backup household generator to run the basics, is the best value for your $.     It takes many hours of burning fuel, at 1 gph, to make up the cost of a $2,000 battery bank that needs replacing every 10 years or more.
    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 ,

  • PhotowhitPhotowhit Solar Expert Posts: 5,909 ✭✭✭✭✭
     Net metering isn’t allowed with Bowie Cass Electric Coop. 
    I know they can be complete jerks about it, and can make it expensive, but it looks like at least at some point, they added the info to their service agreement... it would be worth asking... Looks like they even intended to waive fees for <10kWh connections... Here's a PDF of their agreement (Unless I've got the wrong company)

    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.
  • PhotowhitPhotowhit Solar Expert Posts: 5,909 ✭✭✭✭✭
    If you want to know what things will cost, roughly a 4000 watt array would support a battery bank about 10x it's normal output which would be at NOCT value for the panels, or around 3000 watts for the array. 3000watts and charging voltage for a 48 volt ban would be able to supply 3000watts/60volts=50 amps so about a 48 volt 500 amp hour battery bank. Closest thing without hunting would be l-16-6 volt  batteries at around $330 each and you will need 8 of them for a 48 volt battery bank. You will also need a MPPT charge controller, Schneider xw60 or Outback FM60 are around $500 and handle up to 60 amps, I'd suggest an Outback FM80 which would allow you to add about 50% more array and wouldn't cost much more. In addition, you would want a true sine inverter (to make AC from the DC battery current)which could handle about 3-4000 watts Schneider, Outback, Magnum, would start around $1500 and go up. Throw in mounting , combiner box, wiring, a fuse box, lightning protection(E-Panel) at around $600-1200.

    So roughly 8x$330= @$2600 +$500+$1500+$1000 plus whatever mounts/racking costs.

    Expect replacing charge controllers every 10-15 years, Inverters about the same, batteries around 7-10 years, perhaps 12-15 for a forklift, though people new to solar do tend to kill off their first set early.

    It's a similar size system to my current build, I used a smaller inverter for about 7 years. You can read about my build from 2012 and system here. I did build my own combiner box from UL equipment, and got some good deals, I used a forklift battery, a good option, but more demanding of attention... Keeping things cool may be a little difficult in TX.

    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.
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