Hello,

Greetings from India.

I have an offgrid setup at home. 4KW of solar panel installed on roof top. Total 10 solar panels, each panel is of 400w. Voc and Isc of each panel is 45V and 8.4A respectively.
Axpert VM 3, 5KW solar inverter with four 200Ah lead-acid batteries.

The Axpert VM 3 5KW Solar inverter which is 2 yrs old. Recently due to F09 fault, it was repaired by the service engineer. Where they have completely replaced a faulty board.

Now after repair for few days it was working fine then all of sudden since one week the inverter is behaving strangely.

Case 1:
The inverter was automatically going into "Charge Mode" with out any output for load. This was happening randomly without any fault code or warnings. Even when batteries were fully charged.
To solve this, I disconnected and reconnected all the connection such as utility, solar and batteries , restarted the whole system.

Case 2:
Now after solving the above problem a new problem arisen. The inverter is stopped giving output with fault code F59. 
As per manual F59 error is due to high PV voltage. The PV voltage in inverter was 480V. I reduced one panel then restarted the inverter. Then the fault was removed. The inverter was working fine for few days.

Then same F59 came again. I reduced another panel. Then restarted the inverter. Now it works fine. However before repair I was using the same 10 panels with the inverter it was working fine and great.

The question is how and what happened with the inverter due to which, it is behaving strangely. When I checked using a multimeter today, the PV voltage was showing 350V with 8 panel in series but the inverter was showing 402V. From where this extra 50V is coming. With 10 panel in series multimeter shows 435V while the inverter shows 490V. The max PV input voltage for the inverter is 500V.

How can I solve this problem? Do I need another repair or what? Please guide me.

Any kind of help is highly appreciated. I have attached the inverter settings and pictures for your reference.

Regards,
Rajkumar

Edited September 21, 20232 yr by rajkumar.b
added salutation

 

When I checked using a multimeter today, the PV voltage was showing 350V with 8 panel in series but the inverter was showing 402V. From where this extra 50V is coming.

That pretty much has to be a hardware fault. My guess is that the conformal coating was disturbed with the last repair, and the sensing resistors have absorbed moisture, causing the inverter to measure a higher than actual voltage.

The relevant parts cost only a few US cents each, and only about 3-4 will be involved, for what it's worth.

Thanks for your reply and suggestion Coulomb.

I'll contact the engineer to fix it.

If I don't do anything, then will the inverter cause any trouble in future?

 

 

If I don't do anything, then will the inverter cause any trouble in future?

It's hard to predict all the possible effects of this problem. The firmware will be acting under the impression that there is more PV power than there really is, and that the PV voltage is excessive when it's not.

 

Thanks for your reply and suggestion Coulomb.

I'll contact the engineer to fix it.

If I don't do anything, then will the inverter cause any trouble in future?

 

Just to be 100%sure of the error reading I would also just confirm the multimeter reading with another multimeter. 

Thanks for your replies guys.

I checked with two multimeters and the readings were same.
Fault is in the inverter.

Hello

I had the same error (f 59) (10 solar panel 550 w. installed in series + voltronic 5,5k)

I resolved the error following those steps :

I didn't removed any panels to reduce the voltage 

I reorganized the panels in two parts (in series as well)

So instead of installing all in series and having a over voltage which cause the cutoff of power 

From inverter house,

I divided them in two series separated groups and the result was satisfying (lower voltage)

 

It's a practical way to resolve this issue without losing the juice of removed panels.

 

It's working properly since 10 days till now 🤞🤞🤞

 

rajkumar.b I have the same error F59 with only 5 PV modules. The inverter seems to be working fine (PV input = 185V) and randomly, without any apparent cause, it reports 600V on the PV input, 28.6A current, 6.4kW input power, 70V battery voltage and 300A charging current. The weather is cloudy... The inverter was working fine for 3 years

15 hours ago, Enrico M said:

The inverter seems to be working fine (PV input = 185V) and randomly, without any apparent cause, it reports 600V on the PV input, 28.6A current, 6.4kW input power, 70V battery voltage and 300A charging current.

Many crazy measurements usually means a problem with the -12 V power supply. That causes problems for the op-amps used in nearly all measurements.

Thank-you Coulomb you are very kind, I'll try to do some tests on the circuits