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MPPT Smart Solar Controller

I have a 110/20 MPPT Smart Solar Controller connected to 2 170 watt flexible solar panels on a sailboat. It has been working flawlessly for 2 years. Last week it shut off and and I can not get it to work. The app says the controller is off due to low voltage from the PV.

I took voltage readings at the solar breaker with the breaker off and get 51.5 V on the PV side and 0 V going to the controller. At the controller I get 13.4V on the battery side and 0 on the PV side.

With the breaker open, I get 13.4 volts everywhere.

The batteries were pretty full so I discharged them a bit and get similar results, just lower battery readings.

The controller has a slow six blinks on the blue light.

I have a spare and am going to switch it out but thought I would check here first.

Any ideas?

MPPT SmartSolar
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kevgermany avatar image kevgermany ♦♦ commented ·
What do you mean by open and off?
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svcg avatar image svcg kevgermany ♦♦ commented ·

When I pull up the controller in the Victron Connect app it says it is off. When I click on the icon that tells you why it is off it says there is not enough voltage from the panels. It can also be manually turned off in the app but I have only done this to try and reset it.

When the breaker is in the open position, the circuit is broken. When the breaker is in the closed position, the circuit is closed and everything should be operating.

I hope this makes sense.

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kevgermany avatar image kevgermany ♦♦ svcg commented ·
The breaker is between the panels and the MPPT?

If that's the case, you appear to be saying that when the panels are disconnected (breaker open) you get 13.4V everywhere, battery voltage, e.g. at the output of the breaker. And that when you connect the panels there's 0V on the breaker output?

I'm missing something here.


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svcg avatar image svcg kevgermany ♦♦ commented ·
Sorry, I am not explaining this correctly. The breaker is between the panels and the controller. With the breaker shut off and the circuit disconnected, I get 51.5V at the PV side of the breaker. with the breaker engaged and the circuit in use, I get battery voltage everywhere. It seems like the controller is not recognizing the voltage from the solar panels. I never get 51V at the controller and the controller is not doing anything. But I think the panels are producing the correct voltage.
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klim8skeptic avatar image klim8skeptic ♦ svcg commented ·

@SVCG If your PV voltage sits near the battery voltage, it is likely to be an array fault.

Test a solar panel. Check your panels. Then check the cables, breakers, connectors between the panels and mppt.

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svcg avatar image svcg klim8skeptic ♦ commented ·
Thanks for the advice. I guess when I read 51V on the multi meter at the breaker that led me to believe the panels were working fine. It's only when they are connected to the controller that I read battery voltage. How could there be an array fault if they are producing power?
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klim8skeptic answered ·

@SVCG How could there be an array fault if they are producing power?

Power = volts x current.

Your array is not producing power as it can not deliver current.

Somewhere in your panel, or array wiring there is a high resistance connection that is not allowing current to pass.

Mppt's work by drawing current from the panels, the higher the current, the lower the PV voltage. The mppt calculates the power available, and varies the current drawn to achieve the highest power output.

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svcg avatar image svcg commented ·
Thanks, I should have used the word voltage, not power. It's a simple system, 2 panels with three MC4 connectors. I will start looking for a fault somewhere.
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