Opinions about setting up solar panels purchased

exodus125exodus125 Registered Users Posts: 17 ✭✭
Hello, this is my first post. I purchased a solar power setup used last year and wanted opinion as far as best way to set it up for my application. I live in south Florida and would ideally like to only bring out panels when I need them (so a temporary mount type set up) after a hurricane. That is the only time I would need the panels to charge the bank of batteries I have. I would like to post all the items I have. The only thing I really need to buy to set up is the wiring I believe, but have not bought anything because I am not too sure best way to set up. Before I do a long post with all the parts I have, I want to be sure this is where I should be posting. Thanks in advance for your time and help. 


  • BB.BB. Super Moderators, Administrators Posts: 31,613 admin
    Welcome to the forum Exodus,

    Sure, post your system components.

    Do you have any batteries yet? Do you have them under charge/float?

    When temporary mounting solar panels, making sure they don't get blown over, hit by flying rocks while mowing, and don't "walk away" when you are not home, etc., will help keep your system working.

    Do you have a backup generator of some sort?

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • exodus125exodus125 Registered Users Posts: 17 ✭✭
    Thanks for the warm welcome. 

    So this is what I have:

    8- trojan t105 6v batteries
    11- solar panels 
    3- prostar30 controllers
    1 - chargemaster 12/100-3 automatic battery charger
    1- enag 2000 watt 12v pure sine inverter

    i was told this system was mounted on a yacht, not sure if some of these things are not compatible for home use and may be more for marine use. 

    Batteries are not on a float system but I charge them once a month. They are not hooked up to anything. I also do have a propane generator. 
  • exodus125exodus125 Registered Users Posts: 17 ✭✭
    Here is the info on the solar pannels
  • exodus125exodus125 Registered Users Posts: 17 ✭✭
    This is how the batteries are hooked up to supply 12v. Again, batteries are not hooked up to anything and are charged once a month using the listed charger. 
  • mountainmanmountainman Registered Users Posts: 439 ✭✭
    900 ah @12 volts is a massive battery. 1100 panel watts would be ~6℅ charge rate. Trogen recommends 10-13℅. 17-2200 watts.
    Since you're only using it part time the 1100 watts will work. I would get one more panel though and put 4 on each prostar charge controller. The rest of the time the 100 amp battery charger will give you the 11℅ charge rate.
    2kw array 6 345 q cells  make sky blue 60 cc
     6 230ah GC @36 volts 
    18 amp accusense charger. 3650 champion 
  • exodus125exodus125 Registered Users Posts: 17 ✭✭
    Should the batteries be hooked up to a charger all the time even though they are not being used or could they be charged on a schedule, say once a month, as I have been doing? Would there be an issue in using only 3 panels hooked up to one of the controllers and 4 on each of the other two?

    Thanks for the help guys. 
  • mcgivormcgivor Solar Expert Posts: 3,790 ✭✭✭✭✭✭
    Lead acid batteries self discharge over time, the rate of which is influenced by temperature, Trojan website has this information. Depending on the charger it may be be better to do either way, if the charger has multiple stages including float, then constant is ok, if a single stage such as a general automotive type then monthly would be a better choice IMHO. 
    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.
  • mountainmanmountainman Registered Users Posts: 439 ✭✭
    edited August 2019 #9
    Exodus looked up your battery charger it is a 3 stage. 
    You could leave it on the battery. But once a month would be ok also and not run up your power bill.
    What size is your generator? The charger requires 1700 watts at 230 volts. 
    But can also be powered by 115.
    Very nice charger.
    Putting 4 on 2 and 3 on 1 controller would be ok.
    But the controller could take another. So why not use it.
    100 watt panels are not that expensive. Even have free shipping.  With pwm controller such as yours keep the wires from the controller to the panels short. 15 foot or less. And the wires from the battery to the controllers even shorter 5 foot or less. Would like to see a better pic of your inverter.
    2kw array 6 345 q cells  make sky blue 60 cc
     6 230ah GC @36 volts 
    18 amp accusense charger. 3650 champion 
  • exodus125exodus125 Registered Users Posts: 17 ✭✭
    I will get a better picture and specs on inverter tomorrow. Loads of good info from you all. Thank you very much. 

    So the questions about the generator I assume are for me to use the generator to charge the battery bank when the panels fail to do so at night or when it’s cloudy? I know very little about this stuff. I found this set up on offer up which is like a Craigslist and thought it was priced pretty good at $800 and had always wanted to tinker with this kind of stuff. The set up came with 12 panels but as luck would have it one was broken as the guy loaded them up to bring to me. I ended up paying $600 and thought it was a heck of a deal but not sure. 
  • mountainmanmountainman Registered Users Posts: 439 ✭✭
    I'd say so the charger is over a grand. A good hydrometer will tell you the condition of the batteries. 
    2kw array 6 345 q cells  make sky blue 60 cc
     6 230ah GC @36 volts 
    18 amp accusense charger. 3650 champion 
  • BB.BB. Super Moderators, Administrators Posts: 31,613 admin
    You typically want to keep the battery bank (flooded cell lead acid and variants like AGM, etc.) between (roughly) 50% and 100% state of charge....

    Going very often below 50% SoC, and the battery will have less cycle life. Go below ~20% SoC, you run the risk of "reverse charging" a weak cell and ruining (most rechargeable chemistries are very "unhappy" when reverse charged--Take down to zero volts, then "negative" voltage).

    Normally you run a lead acid battery bank between 50% and 90%+ state of charge... You should go over 90% SoC once or a couple times a week. And some folks will run the battery bank between ~50% and 80% and only go 90%+ SoC once a week.

    We normally design a lead acid system to use about 25% capacity overnight/one full day of heavy clouds... And suggest the "optimum" bank to be 4x daily loads (2 days of storage, 50% max discharge).

    Typically, the genset is started in the early morning when your battery bank is around 50% SoC, and recharge to ~80% SoC, then let the sun finish the charge--Or don't worry and run the genset the next morning.

    Usually, the genset is most fuel efficient when heavily loaded (50% to 80% of rated capacity)... As the batteries go over ~80% SoC, the batteries limit the charging current--And instead of wasting genset fuel at 10% of capacity (and near 50% fuel flow), let the solar panel finish charging.

    We are worried about sulfation (don't let Lead Acid batteries set below ~75% state of charge for days/weeks/etc.). However, an actively cycling battery will not sulfate... Just use the genset to bump charge from 50% to 80% when needed (winter, heavy loads, etc.).

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • exodus125exodus125 Registered Users Posts: 17 ✭✭
    I was able to find a manual to the inverter I have. I believe the one I have is an earlier model because it looks a little different but it is an ons 12v 2000 watt. 

  • exodus125exodus125 Registered Users Posts: 17 ✭✭
    edited August 2019 #14
    Also, what could I theoretically power with this power bank and panels? Would a full size refrigerator be ok? 9,000 btu 110v mini split? I think if I can at least power fridge during a week or 2 week outage it would be good. 
  • mountainmanmountainman Registered Users Posts: 439 ✭✭
    I'm sure the guru's here would know the answer. The inverter is 50 Hertz.
    How would that work on 60 Hertz applications?
    2kw array 6 345 q cells  make sky blue 60 cc
     6 230ah GC @36 volts 
    18 amp accusense charger. 3650 champion 
  • mike95490mike95490 Solar Expert Posts: 9,261 ✭✭✭✭✭

    The inverter is 50 Hertz.

    Clocks and motors will run slow.   Motors may be nosier and likely run a bit hotter

    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 ,

  • BB.BB. Super Moderators, Administrators Posts: 31,613 admin
    edited August 2019 #17
    Normally, about 1,800 to 2,000 Watts is the maximum 12 volt AC inverter can supply without going with crazy heavy wiring (still very heavy/short wiring to keep voltage drop low). The recommend wiring/breaker rating for 12 volts would be around:
    • 2,000 Watts * 1/0.85 AC inverter eff * 1.25 NEC continuous current derating * 1/10.5 battery cutoff voltage = 280 Amp @ 12 volt branch circuit wiring/breaker/fuse rating suggested minimum
    Of course, you do not have to run the inverter at 2,000 Watts--If you never run more than 1,000 Watts, you can design the 12 volt wiring for that size inverter (and 1/2 the DC current).

    Watch the Tare losses of the 2kW inverter--Just to turn the inverter "on" could take 20-40 Watts (and some inverters take a lot more). To run smaller loads on this large of inverter--Your solar ends up 50% going to just run the inverter itself--Plus the loads.

    Running a 50 Hz output inverter... Many are switchable between 50 or 60 Hz. Also, check the output voltage. Is it ~115 VAC or 230 VAC? Most 50 Hz system in the world today are 230 VAC.

    I would not run refrigeration/AC compressors that are designed to run a 60 Hz on 50 Hz, the motors will probably overheat and the output cooling output of the systems will probably be much less than expected.

    A 900 AH @ 12 volt battery bank would support (power wise) upwards of 2,225 Watts maximum AC inverter rating (assuming flooded cell lead acid batteries at 250 Watts per 100 AH of battery bank capacity).

    A 5% rate of charge is OK for weekend/sunny summer usage... For daily usage, suggest 10%-13%-20% rate of charge--2x the number of solar panels you have.

    For parallel battery strings, the negative and positive cables should be connected "kitty corner" from each other (bottom left to upper right in your photo) to balance charging and discharging current to all batteries.

    We do keep coming back to what are your load requirements. Air Conditioners and refrigerators (and most well pumps) put your off grid system needs towards a larger system vs a "small" off grid power system.

    Just to run a full size refrigerator on full time off grid solar power system, I would be suggesting that you start with a ~647 AH @ 24 volt battery bank (almost 2x larger than you have today). Just to give you an idea of what "your system" could output:
    • 900 AH * 12 volts * 0.85 AC inverter eff * 1/2 days storage * 0.50 max discharge (longer battery life) = 2,295 WH per day
    If you have a reasonably efficient full size refrigerator which uses 1,500 to 2,000 WH per day (1.5 kWH per day * 365 days per year = 548 WH per year "Energy Star hang tag" rating).

    And your 11x 100 Watts panels in Miami FL, fixed array:

    Average Solar Insolation figures

    Measured in kWh/m2/day onto a solar panel set at a 64° angle from vertical:
    (For best year-round performance)

    Assuming around 4.43 Hours of sun per day (December long term average):
    • 1,100 Watt Solar Array * 0.52 off grid system eff * 4.43 Hours of sun per day (Dec) = 2,534 WH per average December day
    For "base loads", you should only plan on using 50-65% of your "predicted loads"...

    And your battery bank would supply a single refrigerator roughly:
    • 900 AH * 12 volts * 0.85 AC inverter eff * 1/1,500 WH per day fridge = 6 days from 100% to dead batteries
    Or, roughly 3 days of stored energy for just one refrigerator. Our normal AC loads are much larger that "we think", and off grid solar power system produce, is much less.

    Then there are the questions that "hurt":
    • 11x of your solar panels are only "good" for a 12 volt system (2s x 5p = 10 panels for a 24 volt system).
    • These days, large format solar panels are "cheap" these days (200-300 Watt panels are under $1 or even $0.50 per Watt these days). A large solar array for a larger off grid power system is much better built/wired from large format "GT type" solar panels
    • Your battery bank... Even if they are well cared for batteries, after ~5 years, they will probably need to be replaced (especially if stored in Florida heat).
    • And your 50 Hz AC inverter--It could work for some of your loads (chargers for batteries, laptop computers, running TV set, etc.--Check labels for voltage/frequency input). But, in North America, you really need 60 Hz. And if overseas, most 50 Hz appliances run on 230 VAC @ 50 Hz. Your inverter, if old (over 10+ years), is not of great value in the US or your system (most of its lifetime is "gone).
    Building a small system at ~1,000 WH per day (LED lights, laptop computer, LED TV, cell phone charging, RV water pump)--That is a "reasonable" use for your system (perhaps even split into two separate off grid systems).  But even then, you would need a new AC inverter (something in the 300 Watt range), and possible new solar charge controller (at least one new one). And see how it works for you.

    Once you figure out what energy needs you have, then design a system from scratch... I don't think that what you have today will be of much use for a 3.3 to 10 kWH per day system (and these larger systems are not cheap).


    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • exodus125exodus125 Registered Users Posts: 17 ✭✭
    Wow Bill, thank you for all that info. I appreciate the time you took to gather all that info and for your thoughts on the matter. I am wondering if I would be better off trying to sell this stuff and just design a system as you are suggesting. 
  • BB.BB. Super Moderators, Administrators Posts: 31,613 admin
    Thank you for the kind thoughts Exodus.

    It times past, people got surprisingly good money from Craig's List for smaller solar power systems.

    .... However ... At least in our area (SF Bay Area), C.L. seems to be in a bit of depression (low interest in "hard tools" like mills, lathes, saws, machinist's tooling, etc).

    Take the solar panels and charge controllers--split into two (or three) smaller solar power systems and see if you have interest (if you cannot sell as lot/piecemeal). Or--You might have use for 2-3 smaller solar power system (back yard shed, emergency power for cell phone, LED TV, laptop computer, LED lighting, radio when power goes dead--Small and simple).

    I hate to tell you to deep 6 your present system... And I really do not know what your present desires are for a full size off grid/hybrid system.

    If it is for emergency backup power (few days to a couple weeks a year) and if you have natural gas or (can fit) larger propane tanks and a genset--That will keep you running nicely through and after the storms. Even I just store 20 gallons of gasoline and Honda eu2000i genset (fuel preservative, recycle back into vehicles once a year). I get a 1-2 hour power outage a couple times a decade--Just is not cost effective for a "full off grid solar power system". I figure 2 gallons of gas per day--That is 10 days of backup power. More than that, there will be 1,000's to millions of people in very bad shape in our metro region.

    I know that this is a "Solar Forum"--But trying to set realistic expectations is important. I will not tell you not to "do solar". Energy usage is a highly personal set of decisions (and expenses). It has to be (and is) your choices and your money.

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • exodus125exodus125 Registered Users Posts: 17 ✭✭
    Wealth of information. Splitting the system sounds like a good idea. 
  • exodus125exodus125 Registered Users Posts: 17 ✭✭
    What do you guys make of this?? The label originally had 50 hz and 230v but it was changed to 60hz and 115v?
  • BB.BB. Super Moderators, Administrators Posts: 31,613 admin
    Looks like the factory did a one off (or small pre-production run for marketing tests)--I would guess you have a 115 VAC @ 60 Hz 2kWatt AC inverter.

    Power it up and see how well it runs... Need more information to figure out if TSW or MSW. And a current clamp meter on the DC side to see what the Tare losses are (DC power with inverter "turned on" and no loads).

    This company?


    I am guessing an older unit... May be difficult to find any information online or about the company.

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • exodus125exodus125 Registered Users Posts: 17 ✭✭
    So we dodged a huge bullet here is south Florida with hurricane Dorian!

    if I were to get an all in one type battery bank like the goal zero cube, what would be something I could realistically keep charged with a days amount of sunlight and how many panels would I need? I am thinking of keeping maybe 4 panels and just getting an all in one unit that I can hopefully just hook the panels to and keep maintained by plugging to wall and selling everything else. Maybe something I can run a small fan off of and maybe a mini fridge or even a 12v fridge. 

  • mike_smike_s Registered Users Posts: 131 ✭✭
    I see date codes on the batteries for years ending in 5, 6, and 7. Was the used system really < 5 years old, or might the batteries be as old as 2005? I'd do a test to see how much life is left in them before thinking I could power something for any length of time.

    Also, I don't see any connection coming off the bank's positive rail - make sure it connects to the upper right (diagonal from the negative rail connection), so the batteries are loaded equally.
  • exodus125exodus125 Registered Users Posts: 17 ✭✭
    Just checked the date codes and they are all B8 which would date the batteries to feb 2008. How much do you think these batteries are worth given the age? I charged them about a week ago and they are at 12.64 v when they are all connected together. 
  • EstragonEstragon Registered Users Posts: 4,494 ✭✭✭✭✭
    At 11yrs old, likely just scrap/core charge value.  That varies, currently ~$30ea around here.
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • exodus125exodus125 Registered Users Posts: 17 ✭✭
    What do you guys recommend  if I go with a lifepo4 set up? I have the 11 panels I can use to charge the system. Ideally, I would like something that could be charged daily to full capacity using up to the 11 panels or less and I would like to be able to hook up 1 or 2 small fans and be able to  charge phones and laptop daily. Just the essentials. Not sure if something like one of those goal zero cubes would be good enough and less trouble to maintain, but something similar could be built for much less I would imagine. 
  • exodus125exodus125 Registered Users Posts: 17 ✭✭
    do you guys think it is possible to hook up a 9k btu mini split to a lifepo4 bank and if so how big would it have to be and would my ten 12v panels be enough and would it be better to do 24v using the 10?
  • PhotowhitPhotowhit Solar Expert Posts: 5,563 ✭✭✭✭✭
    exodus125 said:
    do you guys think it is possible to hook up a 9k btu mini split to a lifepo4 bank and if so how big would it have to be and would my ten 12v panels be enough and would it be better to do 24v using the 10?
    Well  if you start with loads a very efficient mini split in the 9,000 btu might use 550 watts per hour on high and perhaps 250 watts per hour on lowest setting (completely made up numbers, but  a good guess)
    Over 8 hours it might use 2000 to 4200 watthours.

    Your 11-100 watt panels,  if new would normally produce about 80-85 watts each,  lets fault on the  high side  of 1000 watts every hour in direct sun light with the sun angled within 15 degrees of perpendicular to the panels. With a fixed array   in Miami,   you can expect about 5.5 hours a day with a fixed array in Miami. So maybe 5500 watt    hours coming into the system, the you have losses of 15-20% charging a lead acid battery,  Down to 4500  watt hours, then you lose another 15-20% converting AC to DC and in wiring and charge controller Down to below 4000 watt hours of storage. 

    Not very practical. 
    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.
  • exodus125exodus125 Registered Users Posts: 17 ✭✭
    I contacted the inverter company today. They verified it is a pure sine wave inverter and it is 60 hz. 
  • garynappigarynappi Registered Users Posts: 96 ✭✭
    edited September 2019 #31
     I don't mean to pee on the parade, but here's another perspective from a fellow So. Flo. resident :-)

    I too am a solar newbie, have lived in live in So. Flo. nearly 40 years and face(d) the same issues over the years you have with power availability after storms.

    We came to the conclusion that given the infrequent complete long term power losses, and daytime rainy / cloudy conditions post storm, a genset was convenient and cost efficient enough to be practical over trying to be comfortable with a purely solar system. Florida Flicker and Flash (FP&L) while regularly having short term power glitches has only necessitated my powering up my genset three times since the 80's.

    Back when I got my first genset I lived on a small island next to the ICW, and the worst power incident was after Wilma, we were out of power for several weeks. With my pool filter, clothes dryer (filter and dryer not run simultaneously) refrigerator and 3x 6000 btu window shaker A/C's I was more than comfortable with an 8500 watt genset. Its only shortcoming was/is fuel which is lessened now that Florida has enacted statute 526.143(2) mandating that newly constructed gas stations have the ability to power their pumps when FP&L (in So. Flo.) goes down.

    Today my solar powers my exterior lighting, as well as water feature pumps and if I lose power I kill the genset at night, and still have exterior lighting. I can also power my alarm and surveillance system rather easily with my current system by inexpensively expanding it a bit. 

    At ~ $160 x 8 (~$1280) to replace your aging batteries and selling some of the rest, you could have a decent genset capable of running most of your home and use a skeleton of your current solar system for other purposes?

    PS: My genset only uses 4-6 gallons of fuel a day assuming a 10-12 hour day which while not free at <$15 and it necessitates my making a fuel run once every 5 days to fill my five 5 gallon jerry cans. At every storm sighting that may make So. Flo. landfall I fill up my cans and wait for the worst but expect the best. If the storm passes by, I use the fuel in my cars. 

    Running my genset I can also charge my solar system battery with a charger to keep the battery topped off if we have a cloudy day. 

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