Please can anyone verify my numbers

Makers
Makers Registered Users Posts: 16 ✭✭
Hey everyone,
    

        I am installing solar for the first time. I have read a lot of information. I just need clarification on a few things.

1.) Are my numbers realistic
2.) Is the a way to determine solar output during non PSH
3.) I understand that I have no days of autonomy
4.) I am trying to use a used system, yes I plan on getting new panels just trying to be able to run basic things
5.) All input will be viewed as help;  I'm not an ahole (pinky swear it) Love for all
6.I live on an hawaiian island that is pretty much third world (molokai) So I have very limited access to batteries and things of such


Thank you all for input and help

Comments

  • Estragon
    Estragon Registered Users Posts: 4,496 ✭✭✭✭✭
    From a quick glance... for panel output, assume Vmp is ~70% of STC to account for marine haze and temperature. 
    Off-grid.  
    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
  • Estragon
    Estragon Registered Users Posts: 4,496 ✭✭✭✭✭
    It may also help in getting input from other forum members to describe your string setup etc here without having a link to an external diagram.  It wouldn't load for me when I went back to check something...FWIW.
    Off-grid.  
    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
  • mcgivor
    mcgivor Solar Expert Posts: 3,854 ✭✭✭✭✭✭
    Calculations based on theroy how a system will perform would require accurate measuring of all parameters, even then it would be merely an estimate. Actual performance will reveal the arrays abilities to support loads as well as charge the batteries and the ability of the batteries to support loads overnight. Being this is a used system, it would be advisable to dynamically test it over time with low loads at first, always observing the voltage, especially first thing in the morning, capacity may have been lost so adjustments may need to be made.

    Discharging to 50% daily will dramatically shorten life expectancy of the batteries, it is suggested as a maximum but keeping the depth of discharge at ~30% is more realistic, this will in turn allow some margin of autonomy. My suggestion is start with a very conservative approach to discover any weakness, this will afford you time to make adjustments.
    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.
  • Makers
    Makers Registered Users Posts: 16 ✭✭
    Hey people, thanks for the replies. here is some more information to help out

    Panel VMP new was 15.9V/3.02A
    Panel VOC new was 19.8V/3.35A

    Panel VOC now is 18V/3A 
    I dont have VMP now numbers

    3 Strings of 8 panels in series. 24 total panels

    as far as discharging the batteries to 50% I completely understand what I am doing to their service life. I am building a home off grid, absolutely no access to the grid. This system is meant for me to have enough power to charge phones, use a laptop from time to time and have TV for part time use. I will be upgrading to a larger/newer system in the next year. Also these batteries are the only ones available to me right now without having to pay double the price in shipping. 6v/235 AH $155 a piece. Don't care if I blow them up in a year.

    Hawaii, USA: Annual Weather Averages. August is the hottest month in Hawaii with an average temperature of 80°F (27°C) and the coldest is January at 73°F (23°C) with the most daily sunshine hours at 11 in July. The wettest month is November with an average of 124mm of rain.

    This is the farmers almanac from where I live.
    I am aware that there will be days where I will have no power, there are beaches here for that (thanks rain shadows!)

    I am just looking to see if there were any errors in my system math, or if anyone has a better plan for the panel set up I am working with.
    Also if the picture wont load you can try to click again. It worked for me.

    Thanks again for the help!
  • Makers
    Makers Registered Users Posts: 16 ✭✭
    Also, When I asked if my numbers were realistic, I was asking if my input/output numbers were realistic. I can adjust my output numbers if my input numbers are lower. I just want to connect wires one time in this system. That was the main reason for the post. 


    Thanks Again

  • mcgivor
    mcgivor Solar Expert Posts: 3,854 ✭✭✭✭✭✭
    What controller is being used? Make model, voltage may be an issue.
    The link doesn't work for me either by the way.
    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.
  • Makers
    Makers Registered Users Posts: 16 ✭✭
    I planned on using a $200 amazon CC, but since i made the picture I have a MIdnite Solar Classic 150, also I edited my post to attach the picture, so you should be able to click it, I am a forum idiot.
  • mcgivor
    mcgivor Solar Expert Posts: 3,854 ✭✭✭✭✭✭
    Personally I would use a lower voltage imput to the controller, the Voc could exceed the maximum given the right conditions, perhaps a 6 series 4 parrallel, the primary reason to use a higher voltage, more than double nominal would be to compensate for voltage drop in long distance runs. How far is the controller from the array?   The loads outlined are minimal, there is no mention of a refrigerator, so the battery capacity should be able to support them. 
    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.
  • Makers
    Makers Registered Users Posts: 16 ✭✭
    10 4 on the 6/4 array. seems like the better option. tyvm for the help. understand completely. 
  • littleharbor2
    littleharbor2 Solar Expert Posts: 2,039 ✭✭✭✭✭
    Makers said:


    Hawaii, USA: Annual Weather Averages. August is the hottest month in Hawaii with an average temperature of 80°F (27°C) and the coldest is January at 73°F (23°C) with the most daily sunshine hours at 11 in July. The wettest month is November with an average of 124mm of rain.

     Your peak sun hours are calculated at ( for Honolulu anyway ) 6.71 hours / 5.59 with an average of 6.02 hours. Your hours may be lower if you get a lot of clouds in your particular area.
     These numbers should be used when calculating your solar array's potential output. 

    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.

  • Estragon
    Estragon Registered Users Posts: 4,496 ✭✭✭✭✭
    So assuming Vmp is now ~14.5v, and Imp is ~2.75a, array output in full sun might be about 14.5 x 2.75 x 24 =950 x 70% for heat & haze, so roughly 665w to the controller.

    665 x 5.5hrs worst month full sun equivalent gives you something like 3600wh/day, less 10% CC losses, so 3200wh for battery charging and loads.  Used batteries are a total unknown.  They might have close to rated capacity, or nearly none.  I'd check SG (if flooded) and resting voltage before buying.

    Note that running small loads on a big inverter can be pretty inefficient.  It may have 85% peak efficiency, but with a small load, self-consumption could be more than the actual load.  Just having it on with no loads could run 30-40w.  Also, if the inverter is a modified wave type, running things like laptop charger can run the power brick hotter.  It might be worth seeing what can be run directly from DC, using car/truck adapters.  24v are less common than 12v, but they exist.
    Off-grid.  
    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
  • Makers
    Makers Registered Users Posts: 16 ✭✭
    edited January 2019 #13
    So I have temp installed my system to have cold beer and cordless tool charging available,During final construction of house

     Here's the list

    Battery: Napa GC2 BAT8146 ((6v 235ah) x 4)) $750
    https://www.napaonline.com/en/p/NBP8146

    CC: EPSolar 4210 amazon with warranty and shipping $170
    https://www.amazon.com/gp/product/B077HHYYHT/ref=ppx_yo_dt_b_asin_title_o04__o00_s00?ie=UTF8&psc=1  

    Inverter pure sine 2500W: $300
     https://www.amazon.com/gp/product/B0761JCN5K/ref=ppx_yo_dt_b_asin_title_o08__o00_s00?ie=UTF8&psc=1
    Inverter:

    Panels: 24 (20 year old) 48W panels: Free
    New: 15.9Vmp
               3.02Imp

    Shunts and Battery Monitor: $60

    PV Combiner Box: $160
    https://www.amazon.com/ECO-WORTHY-String-Combiner-Circuit-Breakers/dp/B01N96GJFT/ref=sr_1_3?ie=UTF8&qid=1548022333&sr=8-3&keywords=pv+combiner+box

    MIsc Tools and Wires and breakers $250

    Grand Total: $1690


    Inverter: 24.5W
    Fridge: 120W
    Laptop 60-130W Depending on gaming or not.



    Numbers for the number guys:
    The bottom right number on the left display shows the watts i used running my fridge all night plus 2 10W led lights and the inverter itself, and the power used during the next day. The bottom right number on the right display was close to zero upon non production from the panels at around 6pm the previous night, the numbers evened out around 12:30PM on the following day.

    The shunts show losses in the system due to voltage drops, the numbers given by the CC don't take those into account.
    I need to get bigger wires from the CC to the batteries right now they are 8AWG at 9 feet.

    24 total panels
    Wired 4 panels in series, then paralleled 8 panels. to make 3 strings of 8 panels

    72.1v Voc
    15.6a Isc

    11:40 
    My CC switch to absorb, with a max production before switch of (Estragon, wait for it 667W)


    10:44AM
    Into CC: (52.1V x 12.4A) Out of CC (28.1V x 23.1A)


    9:44AM
    Into CC: (54.0V x 9.7A) Out of CC (27.2V x 19.1A)


    8:30AM
    Into CC: (56.4V x 3.8A)  Out of CC (25.7V x 8.4A)


    7:14 AM
    Into CC: (26.1V  x .2A) Out of CC: (24.5V x .2A)



    Final Thoughts,

    I feel for a $1700-$1800 investment, I win?

    Your thoughts, and thanks again for all the input

  • Estragon
    Estragon Registered Users Posts: 4,496 ✭✭✭✭✭
    Looks like a win to me!
    Off-grid.  
    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
  • littleharbor2
    littleharbor2 Solar Expert Posts: 2,039 ✭✭✭✭✭
    I have admired that Combiner box for a while now. It looks to be well made and a great price for what you get. I actually built my own similar combiner box using hard mounted MC-4 connectors after seeing this one.
     Sounds like you have done pretty well assembling your temp. system.  Hope it works out well for you.

    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.

  • Makers
    Makers Registered Users Posts: 16 ✭✭
    I have admired that Combiner box for a while now. It looks to be well made and a great price for what you get. I actually built my own similar combiner box using hard mounted MC-4 connectors after seeing this one.
     Sounds like you have done pretty well assembling your temp. system.  Hope it works out well for you.
    Its a wonderful combiner box. I needed something weather proof. For its outside. My only real small concerns. It uses 12a fuses for the string breakers and the wires inside are 12awg in between breakers and bus bars. For that short of run. Its fine. BUT for the money....its hard to beat
  • littleharbor2
    littleharbor2 Solar Expert Posts: 2,039 ✭✭✭✭✭
    12 ga. wire should be good for a minimum of 20 amps. so not sure where the issue is. If you need to swap in 15 amp fuses you're still good to go and you shouldn't ever have any higher current in a single string, really few strings are ever higher than 10 amps.

    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.

  • Makers
    Makers Registered Users Posts: 16 ✭✭
    12 ga. wire should be good for a minimum of 20 amps. so not sure where the issue is. If you need to swap in 15 amp fuses you're still good to go and you shouldn't ever have any higher current in a single string, really few strings are ever higher than 10 amps.
    Im 100% good with the 12awg wire. I was just meaning if I had to nitpick. And the size of the fuses doesnt bother either. Just that they are fuses and not really breakers