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Inverter Diagnostics


Chris Chetty

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Hi there, we run an electrical contracting business. Recently we have started receiving a number of requests to assess inverters. Is there any generic diagnostics tools that we can use that on different inverter brands or at least the lost common brands sold locally.

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1 hour ago, Chris Chetty said:

Hi there, we run an electrical contracting business. Recently we have started receiving a number of requests to assess inverters. Is there any generic diagnostics tools that we can use that on different inverter brands or at least the lost common brands sold locally.

Hi Chris, welcome to the forum. 

What exactly do you mean by assess? To test / verify them.? 

Almost all of today's modern inverters  are equipped with user interfaces (text/graphics mode) that not only allow settings but exposes  its modes and status of operation. It also reports warnings and errors. 

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Thank you, we do work for insurance companies. We need to establish if the inverter can be repaired or if it should be replaced. The error code doesn't help with pinpointing the exact fault. We worked on a kodak inverter yesterday with E51 - either surge or overload. The inverter was fitted with a surge arrestor and when we tested the load it was still within range. I spoke to a third party repairer that mentioned that he had a tool or software that he could plug into the inverter to do a full diagnostic test, similar to how you can check the error codes on your car. 

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Good evening Chris

The short answer is no there is no tool that can be used to test and or verify if an inverter is working correctly.

I recently had the opportunity to visit the Segen Solar workshop / repair center and there they test the units by powering the unit up and see what the unit does and then once they know what the unit does and does not do then they decide which action to take, all they do is replace boards until the unit work.

They use Pylontech batteries and if a unit trips a battery they know that the mainboard of the inverter is faulty and then it is replaced and tested further, to test the MPPT they use a high voltage DC power supply and for a load they have a dummy load consisting out of resistors and fans which cools the resistors down. They also connect the unit up to a utility supply and make sure that the unit charges the battery.

I know that BritishRacingGreen received a couple of Kodak inverters which was damaged by the floods in KZN which Segen Solar did not want to repair because of the water damage but other than that I am not aware of any other units that they did not repair under warranty.

Kind Regards

GerhardK83

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@GerhardK83 has pretty much  nailed it as far as my opinion is concerned. There exists no diagnostic tool for most of the inverters on SA market that I am aware of. 

While we in the community have devised methodologies and walkthroughs to assist in repairs, they remain casual and informal as far as business practices are concerned. Almost all inverters are not modular for economical reasons. Therefore they typically have a single main board which account for about 80% of the function. The controller is typically seperate and its interfaces to the main board only allows for critical diagnostics during startup, example soft start evaluation. But it cannot pinpoint the components /subsystems on the mainboards that may be faulty. 

As Gerhardt pointed out, the agents/distributors can therefore only support and repair inverters on board level. The cost of a new main board may easily attribute to 40% of the value of the inverter. 

The OEM provides no schematics and documentation for field and repair personnell, other than a service manual that, in my opinion, is grossly inadequate for purpose. 

 

Edited by BritishRacingGreen
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A lot of errors can often be caused by dry and aged capacitors on the internal power supply circuits. Replace them and the unit can be returned to service. If the unit is more than 18 months old this is often the case especially if the error doesn't make sense in the installation. A quick check is to remove the cover and have a look at the top righthand side and see if any of the capacitors are swollen. Not a 100% guarantee that this isn't the problem if they are fine but if you see a swollen one you know its a problem.

As BRG stated it's mostly enthusiasts doing board level repairs. Errors that typically require major repair works and IMO probably don't justify the repair on an economic basis are:

09- bus soft start failed (usually battery mosfets, output IGBTs)
08 - bus voltage too high
32 - no coms between screen and main CPU (often damage to bus softstart circuit)

 

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16 minutes ago, Shadders said:

A lot of errors can often be caused by dry and aged capacitors on the internal power supply circuits. Replace them and the unit can be returned to service. If the unit is more than 18 months old this is often the case especially if the error doesn't make sense in the installation. A quick check is to remove the cover and have a look at the top righthand side and see if any of the capacitors are swollen. Not a 100% guarantee that this isn't the problem if they are fine but if you see a swollen one you know its a problem.

As BRG stated it's mostly enthusiasts doing board level repairs. Errors that typically require major repair works and IMO probably don't justify the repair on an economic basis are:

09- bus soft start failed (usually battery mosfets, output IGBTs)
08 - bus voltage too high
32 - no coms between screen and main CPU (often damage to bus softstart circuit)

 

Agree,  especially error 09 where you running a business and required to provide a reasonable warranty, then main board replacement is a given. 

The good news is a new OEM board  escalates the machine to status of 'new' again. 

 

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