3 pannels in parallel

cory
cory Registered Users Posts: 1 ✭
in Solar Beginners Corner #1
I have three panels with 18v each in parallel which originally gave 18v but know the controller is saying 23.9v and only 6 amp can anyone tell me what's going on?
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  • Photowhit
    Photowhit Solar Expert Posts: 6,017 ✭✭✭✭✭
    #2
    Sounds like you have changed your method of measuring  the voltage. Perhaps you were using a charge controller to measure the voltage the solar panels were creating while charging, and you later measured  the voltage with a multimeter, which would be open circuit voltage without a load.

    This would correspond with VMP and VOC, such as this label;
    Image result for solar panel label on back 200

    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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  • littleharbor2
    littleharbor2 Solar Expert Posts: 2,122 ✭✭✭✭✭
    #3
    As far as your (apparently) low current, this could be due to your batteries approaching a full state of charge.

    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.

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  • mvas
    mvas Registered Users Posts: 395 ✭✭✭
    #4
    cory said:
    I have three panels with 18v each in parallel which originally gave 18v but know the controller is saying 23.9v and only 6 amp can anyone tell me what's going on?
    Isn't 18 volts ...
    a) way too high for a 12 volt battery bank ?
    b) way too low for a 24 volt battery bank ?

    We need more details ...
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  • NANOcontrol
    NANOcontrol Registered Users Posts: 280 ✭✭✭
    #5
    Can you tell me what is going on? What is the controller telling you that 23.9V is, panel or battery? 18V sounds like panels optimum power point voltage. 23.9 sounds like open circuit voltage for panel. Sounds a little high if 6A is flowing anywhere. Is that in or out of controller?
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  • garynappi
    garynappi Registered Users Posts: 120 ✭✭
    #6
    mvas said:
    cory said:
    I have three panels with 18v each in parallel which originally gave 18v but know the controller is saying 23.9v and only 6 amp can anyone tell me what's going on?
    Isn't 18 volts ...
    a) way too high for a 12 volt battery bank ?
    >>SNIP<<
    We need more details ...
    The charge controller regulates the voltage and current to levels not destructive for batteries. 


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  • littleharbor2
    littleharbor2 Solar Expert Posts: 2,122 ✭✭✭✭✭
    #7
    Here's the data from a 175 watt, 12 volt panel. Are your panels this size, power wise?

    Electrical Data
    Maximum Power Output:
    175 Watts
    Max Operating Voltage (Vmp):
    18.95 Volts
    Max Operating Current (Imp):
    9.50Amps
    Open Circuit Voltage (Voc):
    23.90 Volts
    Short Circuit Current (Isc):
    9.87 Amps
    Module Efficiency:
    17.0%

    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.

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  • NANOcontrol
    NANOcontrol Registered Users Posts: 280 ✭✭✭
    #8
    Lot bigger panels than I expected. Everything sounds like it is doing just what it is supposed to do.
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