Growatt 5KW fault code 61

[Adnano]

Hello folks,

I am facing an issue with a Growatt inverter which is making me crazy, it gives a fault code 61 (PV voltage is too high). THe LCD display shows a 530V PV voltage!

I measured the two points of IC output marked on the image below, it says 11.6V.

The issue exists when putting the MPPT  board in place, so when disconnecting the NEGATIVE bus voltage, it is working without the problem.

I have tried to remove all components each one to check if any causing this issue, with no success!

I replaced the 330K resistors as well.

First question, is the IC of voltage and current measurement is TL072?

Second question, what do you think is causing such issue?

[Antonio de Sa]

36 minutes ago, Adnano said:

Hello folks,

I am facing an issue with a Growatt inverter which is making me crazy, it gives a fault code 61 (PV voltage is too high). THe LCD display shows a 530V PV voltage!

I measured the two points of IC output marked on the image below, it says 11.6V.

The issue exists when putting the MPPT  board in place, so when disconnecting the NEGATIVE bus voltage, it is working without the problem.

I have tried to remove all components each one to check if any causing this issue, with no success!

I replaced the 330K resistors as well.

First question, is the IC of voltage and current measurement is TL072?

Second question, what do you think is causing such issue?

@Adnano 530 V PV voltage is to high, Max MPTT on the 5 KW inverter is 450 Volts. you are going to fry the MPTT control card.

 

[zsde]

What panel arrangement are you running?
Have you measured the voltage on the MPPT input side, i.e. the actual voltage on the panel DC supply to validate

[Adnano]

Guys there is no PV connected

This is happening without applying solar voltage

[zsde]

45 minutes ago, Adnano said:

Guys there is no PV connected

Apologies, that wasn't quite clear in your original post.

@BritishRacingGreen may be able to give some guidance

[BritishRacingGreen]

3 hours ago, zsde said:

Apologies, that wasn't quite clear in your original post.

@BritishRacingGreen may be able to give some guidance

 

Hi @Adnano  I don't know Growatt that well , but I have seen enough of its inner to know that many of the subsystems are derivatives of the Voltronic Axpert technology.  The fact that you are reading a display of 530V prompts me to believe  that the differential instrumentation amplifier that scales down high pv input to a representative 3.3V swing , are missing the negative opamp supply rail. Typically the opamp has a +12VDC on its +supply  pin , and a -12VDC on its -supply pin. This is of course relative to the system 0V (not to be confused with the actual pv power rails. It sometimes happen on an Axpert that the -12V regulator fails to a state where it has a low impedance to 0v . This effectively results in the opamp having a 12V supply wrt 0v , instead of having a +12V and -12V wrt to 0V. The opamp , while not faulty , cannot operate near its rail voltages and this results in the opamp output being driven very close to its 3.3v maximum, which represents the highest reading , hence the 530V value on display.

So most probably your opamp negative rail is at fault.

 

for further reading , have a look at my link below:

 

[Adnano]

Thanks @BritishRacingGreen for your detailed expalanation, much appreciated.

So principally, I should look into - 12V regulator circuit (LM7912 and capacitors) 

[BritishRacingGreen]

5 minutes ago, Adnano said:

Thanks @BritishRacingGreen for your detailed expalanation, much appreciated.

So principally, I should look into - 12V regulator circuit (LM7912 and capacitors) 

yes sir . Of course we cannot rule out the possibility of the opamp itself going faulty and producing its max output. But I haven't encountered that yet myself.

[Adnano]

The voltage between +Vc and -Vc is correct = 24V

The output of phase A is a +12V which is causing the 530V

I don't know the source of this voltage 

[BritishRacingGreen]

19 minutes ago, Adnano said:

The voltage between +Vc and -Vc is correct = 24V

The output of phase A is a +12V which is causing the 530V

I don't know the source of this voltage 

By output  I assume you mean the output of the opamp . The +12V is indeed causing the full swing in reading. I think the cause is now limited to the opamp being faulty or there may be dry joints in the resistor strings. you will have to check for continuity.

 

If you are able to short circuit the + and - differentials inputs to the opamp , the output should go to zero volts. if not its probable the opamp that needs replacement.

 

[Adnano]

Finally i have got this resolved, 

The issue was existing in the resistor between op amp output and negative input, having the value 7.5 kOhm

Thanks everyone for the brilliant collaboration

[BritishRacingGreen]

9 hours ago, Adnano said:

Finally i have got this resolved, 

The issue was existing in the resistor between op amp output and negative input, having the value 7.5 kOhm

Thanks everyone for the brilliant collaboration

well done , makes sense as that resistor is the gain / attenuation component , and the failure led to the opamp driving max output.