Help needed with repair of an Enecsys SMI480-60 Solar inverter

Thread Starter

Nicootje

Joined Apr 10, 2021
3
Hello,

i am trying to repair an Enecsys SMI 480-60 Solar inverter.

I was looking for a schematic on the internet for quit a long time and finally found a schematic on this forum wich is very great.
This thread: https://forum.allaboutcircuits.com/threads/solar-micro-inverter-power-management.134979/

I inspected the unit en found no burned components, the fuse is ok and there are no short-circuited power mosfets.

This inverter behaves as follows when it is connected to the 220 volts and the solar panels are connected:
- on a properly functioning inverter, the yield of these panels is approximately 31 watts just before conversion;
- on the enecsys inverter everything stays at 0 for about 2 minutes;
- after about 2 minutes, my power meter indicates 2 watts as yield (or decrease) and about 41 VA (apparent power);
- shortly afterwards everything goes back to 0 and it stays that way.

It looks like the DC circuit is okay and there is an error somewhere that shuts things down.

I hope someone can point me in a direction to track down and fix this error?
 

CD4046

Joined Sep 13, 2021
2
Hello!

I may have a solution to your problem.

There are a few op-amps on the board.
Check them for extensive heat buildup - this should not happen.
I would recommend using a thermal camera as it measures without electrical conductivity.
If one of them gets warm, change it and try again.

Could you provide your schematic to us? The link is not helpful at all as there is no such file.

Good luck with your inverter! :)
 

Irving

Joined Jan 30, 2016
3,002
Hello!

I may have a solution to your problem.

There are a few op-amps on the board.
Check them for extensive heat buildup - this should not happen.
I would recommend using a thermal camera as it measures without electrical conductivity.
If one of them gets warm, change it and try again.

Could you provide your schematic to us? The link is not helpful at all as there is no such file.

Good luck with your inverter! :)
With respect that's not a solution, just very general guidance, and a thermal camera is a nice to have; most people won't have access to one.

The schematic is an attachment to the first post in the link above, so the link is very helpful.

@Nicootje - MPPT inverters are tricky beasts - to best advise you, we need to know first what is your level of experience/expertise with this sort of repair and on high-voltage equipment? What test equipment do you have available?
 

Thread Starter

Nicootje

Joined Apr 10, 2021
3
Thanks for all comments.

I am 65 years old and an expercienced electronics hobbyist with electronic education .
I now the danger of high voltage and how it can destroy testing equipment.
I do not have an thermal camera. But i have a laser thermal gun from aliexpress:)

I repaired an Soladin 120/54 and a gti-500W. But they had simple to repair problems.

I am having an multi-meter, an USB-osciloscope with a differential input extension, a loupe and mini soldering iron.
I can replace simple smd-devices but replacing ic's with a lot of micro-pins is a way to fa for mer.
 

CD4046

Joined Sep 13, 2021
2
Hey! :)

I can replace simple smd-devices but replacing ic's with a lot of micro-pins is a way to fa for mer.
Here are four ways shown:
I would recommend the last method. You can also achieve it with only one iron: Heat only one row of pins and lift it up about 2mm. After that, you can clean the pads underneath with solder wick and heat the remaining side and lift the IC off with a pair of tweezers.
Warning: This method can get you into trouble on old, instable boards as it means mechanical stress to the PCB and the pads. You have to be careful and I would recommend to try on a scrap board first before working on the board you want to fix. And you´ll need a proper iron with the right tip and enough power to heat all pins on one side at once.

Back to (what I think could be) your problem:
When I was expressing my guess I was thinking back to this thread in the EEVBlog-forum:
https://www.eevblog.com/forum/repair/repair-of-enecsys-smi-d360w-72-micro-inverter/
Maybe its helpful to you. Did you make progress in the meantime?
With how much DC voltage did you test the inverter and how high was the current consumption? Can you get the MPPT into action when you decrease the current limit of the power supply after startup?

A laser thermometer will work just fine, the thermal camera has the advantage that the whole board can be monitored at the same time.
Good to know that you know what you are doing. ;)

@Irving Yeah, you´re absolutely right - the link contains the schematic. I messed up with many tabs in my browser and tought the link would guide one to another website. My fault, sorry.
 

Thread Starter

Nicootje

Joined Apr 10, 2021
3
Hey! :)



Here are four ways shown:
I would recommend the last method. You can also achieve it with only one iron: Heat only one row of pins and lift it up about 2mm. After that, you can clean the pads underneath with solder wick and heat the remaining side and lift the IC off with a pair of tweezers.
Warning: This method can get you into trouble on old, instable boards as it means mechanical stress to the PCB and the pads. You have to be careful and I would recommend to try on a scrap board first before working on the board you want to fix. And you´ll need a proper iron with the right tip and enough power to heat all pins on one side at once.

Back to (what I think could be) your problem:
When I was expressing my guess I was thinking back to this thread in the EEVBlog-forum:
https://www.eevblog.com/forum/repair/repair-of-enecsys-smi-d360w-72-micro-inverter/
Maybe its helpful to you. Did you make progress in the meantime?
With how much DC voltage did you test the inverter and how high was the current consumption? Can you get the MPPT into action when you decrease the current limit of the power supply after startup?

A laser thermometer will work just fine, the thermal camera has the advantage that the whole board can be monitored at the same time.
Good to know that you know what you are doing. ;)

@Irving Yeah, you´re absolutely right - the link contains the schematic. I messed up with many tabs in my browser and tought the link would guide one to another website. My fault, sorry.
Thanks for your comment. I did not test further. In summer i like to sit outside with a cold beer. I will go further testing this winter and will report my findings.
 

Irving

Joined Jan 30, 2016
3,002
The easiest way to remove multi-pin SMD parts (not leadless/BGA) is with ChipQuik low-melt solder. I've successfully used this to remove 144-pin packs. Even easier with hot air station.
 
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