question

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crazydoc asked

Lost Solar

Hi . Sometime it looks like solar yield doesnt go through to the batteries or inverter. It doesnt show any solar on the dashboard and then suddenly it starts again utilising my solar. My service support says that because we only have 4 solar pannels (2 in series each ie 48 volt batteries) that we d onot generate enough voltages to charge the batteries or let the system work. But then the sun is shining hot outside producing enough energy. As you can hear ,im no boffin, but surely the mppt can convert a low voltage into 48 -59 volt by reducing the current and that this expalination doesnt explain why the system sometimes ignore any solare yielded?? . 48 volt victron with gx and 35/150 mppt. many thanks

MPPT Controllers
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2 Answers
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wkirby answered ·

The Victron MPPT controllers (and most others on the market) are Buck Converters. This means they only step down the Voltage, they cannot step up.
The PV Voltage needs to be 5V higher than the battery Voltage for the converter to start up and once started the PV Voltage needs to be 1V or more above battery Voltage for it to keep running.
If your actual battery Voltage is 48V and your PV Voltage goes below 49V then the converter will stop and not start again until the PV goes above 54V.

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crazydoc answered ·

Hi WKirby. Thanks for your answer. I checked my pv voltage now, sun shining outside. 69 volt on mppt. Battery voltage 51 volt on mppt. Is this 69 not way enough? And my system show solar yield 0 watts. ?? many thanks

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