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Dan Blank avatar image
Dan Blank asked

Minimum panel voltage PWM

Hi, I understand there's a minimum PV input voltage for MPPT that's vBatt +5v. Is there a similar minimum for PWM? Specifically BlueSolar PWM Charge Controller (DUO) LCD&USB ? I have a small panel and battery that technically needs a controller, and I'm below the threshold for MPPT.

BlueSolar PWM
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Justin Cook avatar image
Justin Cook answered ·

You'll need 15-28v on the solar input if you're charging a 12vNom bank - the specifications are listed in the user manual here: https://www.victronenergy.com/upload/documents/Manual-BlueSolar-PWM-DUO-12V-24V-20A-LCD-USB-EN-NL-FR-DE-ES-SE-IT-CZ-RU.pdf


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Dan Blank avatar image
Dan Blank answered ·

Thanks. It's not clear whether there's an activation voltage, as is the case for MPPT. I'll assume not?

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Justin Cook avatar image Justin Cook ♦♦ commented ·
It's safe to say that if your panel voltage is below the minimum voltage listed, it won't work. So, effectively, yes there's an activation voltage - 15v at 12vNom system, or 30v at 24vNom system.
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eric-s avatar image
eric-s answered ·

With a PWM, you are supposed to connect a "12 V" panel to a 12 V batterie. In fact, a "12 V" panel is supposed to have 36 cells with V(max power) around 18-19 V and V(open circuit) around 22 V. Check the label on the back of the panel for such numbers. Such values will allow your PWM to charge correctly your batterie.

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