PV OVER VOLTAGE

KhellSk
KhellSk Registered Users Posts: 91 ✭✭
in Off Grid Solar & Battery Systems #1

Hello all. I have Renogy Pwm charge controller and its been fine until now.


The pv light started flashing fast and manual says it means pv is over voltage. Never had that happen before. I removed the wire going in the cc fom the panels and my battery read 12.9v

Panels are 5x 15.9Vmp 3Amp plus 1x 17Vmp 5.9Amp all in paralelle. What I dont understand is that the sky is heavily covered by clouds like its about to rain or snow.... i shouldnt be at max power specs.

Can anyone help me ? Im afraid to plug it back in

_____________________________________________
[3p3s 48w 15.9Vmp] [Flooded 2x 6v 150ah]
[Victron 50/100 700wMax MPPT]







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  • KhellSk
    KhellSk Registered Users Posts: 91 ✭✭
    #2

    Just plugged it back and it reads 13.1v like i would expect in a day like this.

    Any clues what happened ?

    _____________________________________________
    [3p3s 48w 15.9Vmp] [Flooded 2x 6v 150ah]
    [Victron 50/100 700wMax MPPT]







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  • Estragon
    Estragon Registered Users Posts: 4,496 ✭✭✭✭✭
    #3

    What is the max voltage (Voc) spec for the controller?

    A cool/cold cloudy day with a breeze, and very early in the morning can actually be when the pv voltage is highest. The controller may not be "awake" to actively charge batteries, but with little sun to warm the panels, they stay cold. Panel voltage drops when hot, rises when colder. It takes very little light to get voltage, but with little/no current flow.

    With a pwm controller, the battery would pull pv voltage down when operating, but it may be "sleeping" with not enough light for charging. With a zero duty cycle, the battery may not be pulling pv voltage down, leading to the overvoltage.

    The controller may have a setting for a "soft" overvoltage to set a warning and/or shutdown which is lower than the "hard" overvoltage (at which permanent damage may occur). If so, and depending on how much room you have between the hard and soft overvoltage values, you may be able to nudge the soft warning voltage setting up a bit. You want to be careful doing this though, as hitting the hard limit will likely void warranty and may damage the controller.

    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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  • jonr
    jonr Solar Expert Posts: 1,386 ✭✭✭✭
    #4

    What is the "Max. PV Input Voltage" for your controller? If it's 26V, then extreme cold might be the issue. If it's the 50V model, then maybe lightning.

    I am available for custom hardware/firmware development

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  • KhellSk
    KhellSk Registered Users Posts: 91 ✭✭
    #5

    High Voltage Disconnect: 16V

    Over-Voltage Reconnect: 15V

    Max. PV Input Voltage: 25 VDC

    Here you go. Also about extreme cold. It is spring now. Extreme cold days are long gone and never had it happen during. So not that either. Wasnt lighthening storm either.


    This was past noon. So not the morning thing.

    _____________________________________________
    [3p3s 48w 15.9Vmp] [Flooded 2x 6v 150ah]
    [Victron 50/100 700wMax MPPT]







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  • Photowhit
    Photowhit Solar Expert Posts: 6,006 ✭✭✭✭✭
    #6

    If there were no changes to the system for a week or 2 prior to this, I'd figure I was just a glitch and move on... maybe look around to replace the charge controller if it fails. If it was a MPPT type controller, I might suspect the fan failed and it saying over voltage is actually it's inability to dissipate heat.

    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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  • mcgivor
    mcgivor Solar Expert Posts: 3,854 ✭✭✭✭✭✭
    #7

    Have there been any brief sunny breaks in the clouded sky, if so the cold panels suddenly hit by full sun could spike the voltage high enough to cause the controller to go into fault.

    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.
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  • jonr
    jonr Solar Expert Posts: 1,386 ✭✭✭✭
    #8

    > High Voltage Disconnect: 16V

    This number could be reached in any weather. It isn't a good match for a 17+V panel.

    I am available for custom hardware/firmware development

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  • KhellSk
    KhellSk Registered Users Posts: 91 ✭✭
    #9

    @mcgivor probably what happens... makes total sense. Thanks

    _____________________________________________
    [3p3s 48w 15.9Vmp] [Flooded 2x 6v 150ah]
    [Victron 50/100 700wMax MPPT]







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