Solar power charge regulator

kurcklobasa
kurcklobasa Registered Users Posts: 5 ✭✭
in Off Grid Solar & Battery Systems #1
Hello everybody! I could use some help, my knowledge of solar power is not as vast as I would like it to be, therefore i come to you for some assistance :)

The main board of my solar system ZD-SH500H ->http://www.advancedenergysolutionsna.fruitengine.com/solar-power-products.html has gone bad, and i wouldn't like to spend a fortune on a board service. 

Therefore, i wonder if I could connect the solar panels to a new charge regulator, so i could save money, by not fixing the main board (it includes inverter, which i dont really need).

I have 2 batteries, each 12V and 100Ah (lead-acid). Which charge regulator should I use, and do i need a a heat element connected to load output for excess energy?

Thank you in advance!
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #2
    Can you tell us exactly what solar panels you have (such as 2x 200 Watt Vmp=35 volts; Imp=5.7 amps)?

    The details matter... If you have 2x of the above panels connected in series, you can just use a (relatively) inexpensive ~15 amp (or larger) solar charge controller (with 24 volt output).

    https://www.solar-electric.com/residential/charge-controllers.html?manufacturer=Morningstar+Corporation
    https://www.solar-electric.com/midnite-solar-brat-pwm-solar-charge-controller.html

    Or similar (there are lots of inexpensive PWM charge controllers around on EBay and such).

    If your panels are Vmp~30 volts--Then we are looking at more expensive MPPT type charge controllers.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • kurcklobasa
    kurcklobasa Registered Users Posts: 5 ✭✭
    #3
    I would say I have panels as you have described them (200W Vmp=35V; Imp=5,7A) connected in parallel, therefore i think a 15Amp charge controller with 24V output would do. 

    http://www.tmart.com/CMTD-2420-20A-12V-24V-USB-Output-LCD-Display-PWM-Panel-Regulator-Solar-Charge-Controller_p340806.html

    Would this one do? It supports input under 50V, and has a 20A output. 

    I think i will connect my 2 batteries also in parallel, having 12V current and a greater capacity of 200Ah.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #4
    2x 12 volt @ 100 AH batteries, whether in parallel (12 volts @ 200 AH) or in series (24 volts @ 100 AH)--Both store exactly the same amount of energy (Volts*Amp*Hours=Watt*Hours).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • kurcklobasa
    kurcklobasa Registered Users Posts: 5 ✭✭
    edited September 2017 #5
    So this one will do (http://www.tmart.com/CMTD-2420-20A-12V-24V-USB-Output-LCD-Display-PWM-Panel-Regulator-Solar-Charge-Controller_p340806.html) as long as i connect batteries in series, having 24V which means what the current from charge regulator won't exceed 20A (400W / 24V + 25%=20.8A which i would presume is close enough)
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  • Estragon
    Estragon Registered Users Posts: 4,496 ✭✭✭✭✭
    #6
    Unless you're in a cold, high altitude location, you'll likely never get 400w out of 400w STC rated pv, so 20a should be adequate. With your panels and this controller, my guess is you may see ~10a.
    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
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  • kurcklobasa
    kurcklobasa Registered Users Posts: 5 ✭✭
    #7
    Does it matter whether I connect two batteries in series and have 24V or parallel and have 12V?
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  • Estragon
    Estragon Registered Users Posts: 4,496 ✭✭✭✭✭
    #8
    With your panels and a 12v bank, I would use an mppt controller, not pwm.

    What are your loads? You said earlier your dead unit includes an inverter you don-t use, so dc only load(s)? What voltage?
    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
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #9
    Kurcklobasa,

    12 or 24 volts. It depends on your loads. What is their native voltage (i.e., 12 volt radio or 230 vac loads and you purchase the inverter you need).

    More or less, 12 volts for 1,200 watt loafs or less. Loads over 2,000 watts, 24 volts is better. Loads over 4,000 watts, 48 volts ous better (basically keep the DC battery bank current reasonable).

    Like asking if a motorcycle or a truck and trailer is better. It depends on your needs.

    - Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • kurcklobasa
    kurcklobasa Registered Users Posts: 5 ✭✭
    edited September 2017 #10
    Because panels are 35V and i use a PWM charger i think i should set baterries in series, getting 24V. I will primarily use the system for a few 24V LED lights, that I think use 6W each. I also think about setting a small refrigerator (travel like, 24V) that shouldn´t use too much, maybe 60W. And of course some small speakers and a radio, connected to the inverter (i think i only have 300w but it will do for that and for laptop charging). I won't use any big loads, I have a generator for that. Thinking about setting an ampermeter between the battery and loads, just to estimate how much time I could go on in case of a bad weather. 
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #11
    Yep... If your panels (or array) Vmp-array is ~35-40 volts, a PWM type charge controller will work fine.

    There are various DC Amp*Hour and Watt*Hour meters out there:

    http://rc-electronics-usa.com/ammeters/dc-amp-meter.html

    There are now many versions/brands out there these days (China, etc.).

    -Bill

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