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RCT Axpert VMII 2.5Kva Inverter Error 09 (bus soft start failed)

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Hi guys. 

So my inverter is exactly 1 year 2 months old. 

Been using it perfectly fine. 

Today the installers came to put in some solar panels. Whilst connecting the negative PV cable to the inverter, the inverter made a loud pop and switched off. 

Why would this happen if there was no current coming from the negative cable? 

Now whilst powering the inverter up, the inverter is showing error 09( bus soft start failed). 

 

Is this issue repairable ?  

Cant remember exactly how long the warranty is on these units. Can they be repaired out of warranty? 

I am based in Centurion.

 

All help and advice will be highly appreciated. 

5 hours ago, Red Falcon said:

Hi guys. 

So my inverter is exactly 1 year 2 months old. 

Been using it perfectly fine. 

Today the installers came to put in some solar panels. Whilst connecting the negative PV cable to the inverter, the inverter made a loud pop and switched off. 

Why would this happen if there was no current coming from the negative cable? 

Now whilst powering the inverter up, the inverter is showing error 09( bus soft start failed). 

 

Is this issue repairable ?  

Cant remember exactly how long the warranty is on these units. Can they be repaired out of warranty? 

I am based in Centurion.

 

All help and advice will be highly appreciated. 

Did you perhaps see that the negative wire was in fact negative? Something like a test from a multimeter before it was connected. 

There is a guy on the forum in Centurion that can indeed fix this inverter. Just forgot his name. 

  • Author

Yes definitely tested to make sure.  Checked the multimeter myself with installer as I am also quite familiar with electrics and diy. 

Absolutely no current from the negative pv cable. 

 

Just stumped on why it happened. 

 

I'm going to see if still under warranty,  and if not. 

Would appreciate if I can find the person to repair it  

20 hours ago, Red Falcon said:

Yes definitely tested to make sure.  Checked the multimeter myself with installer as I am also quite familiar with electrics and diy. 

Absolutely no current from the negative pv cable. 

 

Just stumped on why it happened. 

 

I'm going to see if still under warranty,  and if not. 

Would appreciate if I can find the person to repair it  

If your machine has a high voltage PV mppt in the range of 400vdc max or higher then I am afraid I am the bearer of bad news. 

 

On 2024/03/30 at 1:03 PM, Red Falcon said:

Whilst connecting the negative PV cable to the inverter, the inverter made a loud pop and switched off. 

This implies that the machine was switched on when the pv was connected, possibly with a screw driver onto the pv input terminals. The screw driver probably momentarily touched the housing which is only about 2mm clearance away. 

The machine is transformerless and inadvertantly earthing one pv input affectively shorts out some igbt's in the dc-ac bridge. This is because one leg of the bridge output is your neatral, which for this understanding, is also earthed. 

This causes the live to short to earth via the igbts and they blow spectaculrly and immediately. 

As a result, next time you switch on, the axpert performs a bus soft start evaluation cycle. The bus voltage cannot reach a certain voltage because of the shorts over the blown igbts. The axpert teports error 09 and aborts.  Almost always will one or more igbt gate driver be also fried. 

Finding a repair person depends on where you are located. 

1 hour ago, Red Falcon said:

So the inverter supposed to have been completely switched off before connecting the PV? 

Yes please. 

I dont per se do repairs myself anymore, but I will get you in touch with 2 very capable young engineers, who will be able to asses the damage and quote accordingly. I will prompt them to PM you. 

  • 3 weeks later...
  • Author

So just an update on this. 

Unit was under warranty. 

So Rectron repaired it within a week.  

Unit is back up and running. And the solar is working well as well. 

Thanks for all the feedback. 

It's much appreciated.  

8 minutes ago, Red Falcon said:

So just an update on this. 

Unit was under warranty. 

So Rectron repaired it within a week.  

Unit is back up and running. And the solar is working well as well. 

Thanks for all the feedback. 

It's much appreciated.  

Great to hear inverter is back in service and also the speedy service you got from Rectron. 

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