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mths asked

SmartSolar MPPT 75/15 output problem

I have a SmartSolar MPPT 75/15 and a 80W panel. I bought them last year and they have been working perfectly. Now, after 1,5 years, the output has dropped. According to Victron app the system output is only 30W. I suspected a faulty panel, but I've started to think it's the MPPT. The solar voltage on the app seems to be fluctuating all the time (in bright & direct sunlight) when the charger is enabled, showing everything between 14.2 and 17.2 volts. When I disable charging on the app, the solar voltage is practically steady 21-22V volts. No fluctuation. This would indicate that the panel is working as it should, giving correct voltage, but there is something wrong with the MPPT controller.


This panel and controlled used to give me 75W, ~18.6V / 4.0A and ~5.8A charging current. Now it's around 30W, ~14-17V / 2.0A and 2.5A charging current in bright & direct sunlight.


I've tried to disconnect and reconnect eveything, reset to factory defaults, but no help. Any idea what to try next?

MPPT ControllersMPPT SmartSolar
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2 Answers
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michelg answered ·

Hi Mths, what firmware version is installed on your mppt ? Try installing the 1.56, it did correct several issues.

Michel

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mths avatar image mths commented ·
I checked the firmware also and it’s the latest available.
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mths answered ·

Case solved. It was a faulty panel after all. I had a chance to troubleshoot and test the panel with another MPPT charge controller.

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